diff --git a/src/libcore/convert/mod.rs b/src/libcore/convert/mod.rs
index eef9ee7cb0093..8ff1ced53b071 100644
--- a/src/libcore/convert/mod.rs
+++ b/src/libcore/convert/mod.rs
@@ -374,6 +374,7 @@ pub trait Into<T>: Sized {
 /// [`Into`]: trait.Into.html
 /// [`from`]: trait.From.html#tymethod.from
 /// [book]: ../../book/ch09-00-error-handling.html
+#[rustc_diagnostic_item = "from_trait"]
 #[stable(feature = "rust1", since = "1.0.0")]
 #[rustc_on_unimplemented(on(
     all(_Self = "&str", T = "std::string::String"),
diff --git a/src/libcore/mem/mod.rs b/src/libcore/mem/mod.rs
index 8bce980cadd1e..066bb8b3dc787 100644
--- a/src/libcore/mem/mod.rs
+++ b/src/libcore/mem/mod.rs
@@ -581,11 +581,12 @@ pub const fn needs_drop<T>() -> bool {
 /// This means that, for example, the padding byte in `(u8, u16)` is not
 /// necessarily zeroed.
 ///
-/// There is no guarantee that an all-zero byte-pattern represents a valid value of
-/// some type `T`. For example, the all-zero byte-pattern is not a valid value
-/// for reference types (`&T` and `&mut T`). Using `zeroed` on such types
-/// causes immediate [undefined behavior][ub] because [the Rust compiler assumes][inv]
-/// that there always is a valid value in a variable it considers initialized.
+/// There is no guarantee that an all-zero byte-pattern represents a valid value
+/// of some type `T`. For example, the all-zero byte-pattern is not a valid value
+/// for reference types (`&T`, `&mut T`) and functions pointers. Using `zeroed`
+/// on such types causes immediate [undefined behavior][ub] because [the Rust
+/// compiler assumes][inv] that there always is a valid value in a variable it
+/// considers initialized.
 ///
 /// This has the same effect as [`MaybeUninit::zeroed().assume_init()`][zeroed].
 /// It is useful for FFI sometimes, but should generally be avoided.
@@ -612,6 +613,7 @@ pub const fn needs_drop<T>() -> bool {
 /// use std::mem;
 ///
 /// let _x: &i32 = unsafe { mem::zeroed() }; // Undefined behavior!
+/// let _y: fn() = unsafe { mem::zeroed() }; // And again!
 /// ```
 #[inline(always)]
 #[stable(feature = "rust1", since = "1.0.0")]
diff --git a/src/libcore/ptr/mod.rs b/src/libcore/ptr/mod.rs
index 1be05d5effff3..172b23a8d5a26 100644
--- a/src/libcore/ptr/mod.rs
+++ b/src/libcore/ptr/mod.rs
@@ -1399,3 +1399,70 @@ fnptr_impls_args! { A, B, C, D, E, F, G, H, I }
 fnptr_impls_args! { A, B, C, D, E, F, G, H, I, J }
 fnptr_impls_args! { A, B, C, D, E, F, G, H, I, J, K }
 fnptr_impls_args! { A, B, C, D, E, F, G, H, I, J, K, L }
+
+/// Create a `const` raw pointer to a place, without creating an intermediate reference.
+///
+/// Creating a reference with `&`/`&mut` is only allowed if the pointer is properly aligned
+/// and points to initialized data. For cases where those requirements do not hold,
+/// raw pointers should be used instead. However, `&expr as *const _` creates a reference
+/// before casting it to a raw pointer, and that reference is subject to the same rules
+/// as all other references. This macro can create a raw pointer *without* creating
+/// a reference first.
+///
+/// # Example
+///
+/// ```
+/// #![feature(raw_ref_macros)]
+/// use std::ptr;
+///
+/// #[repr(packed)]
+/// struct Packed {
+///     f1: u8,
+///     f2: u16,
+/// }
+///
+/// let packed = Packed { f1: 1, f2: 2 };
+/// // `&packed.f2` would create an unaligned reference, and thus be Undefined Behavior!
+/// let raw_f2 = ptr::raw_const!(packed.f2);
+/// assert_eq!(unsafe { raw_f2.read_unaligned() }, 2);
+/// ```
+#[unstable(feature = "raw_ref_macros", issue = "73394")]
+#[rustc_macro_transparency = "semitransparent"]
+#[allow_internal_unstable(raw_ref_op)]
+pub macro raw_const($e:expr) {
+    &raw const $e
+}
+
+/// Create a `mut` raw pointer to a place, without creating an intermediate reference.
+///
+/// Creating a reference with `&`/`&mut` is only allowed if the pointer is properly aligned
+/// and points to initialized data. For cases where those requirements do not hold,
+/// raw pointers should be used instead. However, `&mut expr as *mut _` creates a reference
+/// before casting it to a raw pointer, and that reference is subject to the same rules
+/// as all other references. This macro can create a raw pointer *without* creating
+/// a reference first.
+///
+/// # Example
+///
+/// ```
+/// #![feature(raw_ref_macros)]
+/// use std::ptr;
+///
+/// #[repr(packed)]
+/// struct Packed {
+///     f1: u8,
+///     f2: u16,
+/// }
+///
+/// let mut packed = Packed { f1: 1, f2: 2 };
+/// // `&mut packed.f2` would create an unaligned reference, and thus be Undefined Behavior!
+/// let raw_f2 = ptr::raw_mut!(packed.f2);
+/// unsafe { raw_f2.write_unaligned(42); }
+/// assert_eq!({packed.f2}, 42); // `{...}` forces copying the field instead of creating a reference.
+/// ```
+#[unstable(feature = "raw_ref_macros", issue = "73394")]
+#[rustc_macro_transparency = "semitransparent"]
+#[allow_internal_unstable(raw_ref_op)]
+pub macro raw_mut($e:expr) {
+    &raw mut $e
+}
diff --git a/src/libcore/result.rs b/src/libcore/result.rs
index c7b5777a16e7f..2080ae193667e 100644
--- a/src/libcore/result.rs
+++ b/src/libcore/result.rs
@@ -1145,45 +1145,69 @@ impl<T, E: Into<!>> Result<T, E> {
     }
 }
 
-#[unstable(feature = "inner_deref", reason = "newly added", issue = "50264")]
+#[unstable(feature = "inner_deref", issue = "50264")]
 impl<T: Deref, E> Result<T, E> {
-    /// Converts from `Result<T, E>` (or `&Result<T, E>`) to `Result<&T::Target, &E>`.
+    /// Converts from `Result<T, E>` (or `&Result<T, E>`) to `Result<&<T as Deref>::Target, &E>`.
     ///
-    /// Leaves the original `Result` in-place, creating a new one containing a reference to the
-    /// `Ok` type's `Deref::Target` type.
+    /// Coerces the [`Ok`] variant of the original [`Result`] via [`Deref`](crate::ops::Deref)
+    /// and returns the new [`Result`].
+    ///
+    /// # Examples
+    ///
+    /// ```
+    /// let x: Result<String, u32> = Ok("hello".to_string());
+    /// let y: Result<&str, &u32> = Ok("hello");
+    /// assert_eq!(x.as_deref(), y);
+    ///
+    /// let x: Result<String, u32> = Err(42);
+    /// let y: Result<&str, &u32> = Err(&42);
+    /// assert_eq!(x.as_deref(), y);
+    /// ```
     pub fn as_deref(&self) -> Result<&T::Target, &E> {
         self.as_ref().map(|t| t.deref())
     }
 }
 
-#[unstable(feature = "inner_deref", reason = "newly added", issue = "50264")]
+#[unstable(feature = "inner_deref", issue = "50264")]
 impl<T, E: Deref> Result<T, E> {
-    /// Converts from `Result<T, E>` (or `&Result<T, E>`) to `Result<&T, &E::Target>`.
+    /// Converts from `Result<T, E>` (or `&Result<T, E>`) to `Result<&T, &<E as Deref>::Target>`.
     ///
-    /// Leaves the original `Result` in-place, creating a new one containing a reference to the
-    /// `Err` type's `Deref::Target` type.
+    /// Coerces the [`Err`] variant of the original [`Result`] via [`Deref`](crate::ops::Deref)
+    /// and returns the new [`Result`].
     pub fn as_deref_err(&self) -> Result<&T, &E::Target> {
         self.as_ref().map_err(|e| e.deref())
     }
 }
 
-#[unstable(feature = "inner_deref", reason = "newly added", issue = "50264")]
+#[unstable(feature = "inner_deref", issue = "50264")]
 impl<T: DerefMut, E> Result<T, E> {
-    /// Converts from `Result<T, E>` (or `&mut Result<T, E>`) to `Result<&mut T::Target, &mut E>`.
+    /// Converts from `Result<T, E>` (or `&mut Result<T, E>`) to `Result<&mut <T as DerefMut>::Target, &mut E>`.
     ///
-    /// Leaves the original `Result` in-place, creating a new one containing a mutable reference to
-    /// the `Ok` type's `Deref::Target` type.
+    /// Coerces the [`Ok`] variant of the original [`Result`] via [`DerefMut`](crate::ops::DerefMut)
+    /// and returns the new [`Result`].
+    ///
+    /// # Examples
+    ///
+    /// ```
+    /// let mut x: Result<String, u32> = Ok("hello".to_string());
+    /// let y: Result<&mut str, &mut u32> = Ok("HELLO");
+    /// assert_eq!(x.as_deref_mut().map(|x| { x.make_ascii_uppercase(); x }), y);
+    ///
+    /// let mut x: Result<String, u32> = Err(42);
+    /// let y: Result<&mut str, &mut u32> = Err(&42);
+    /// assert_eq!(x.as_deref_mut().map(|x| { x.make_ascii_uppercase(); x }), y);
+    /// ```
     pub fn as_deref_mut(&mut self) -> Result<&mut T::Target, &mut E> {
         self.as_mut().map(|t| t.deref_mut())
     }
 }
 
-#[unstable(feature = "inner_deref", reason = "newly added", issue = "50264")]
+#[unstable(feature = "inner_deref", issue = "50264")]
 impl<T, E: DerefMut> Result<T, E> {
-    /// Converts from `Result<T, E>` (or `&mut Result<T, E>`) to `Result<&mut T, &mut E::Target>`.
+    /// Converts from `Result<T, E>` (or `&mut Result<T, E>`) to `Result<&mut T, &mut <E as DerefMut>::Target>`.
     ///
-    /// Leaves the original `Result` in-place, creating a new one containing a mutable reference to
-    /// the `Err` type's `Deref::Target` type.
+    /// Coerces the [`Err`] variant of the original [`Result`] via [`DerefMut`](crate::ops::DerefMut)
+    /// and returns the new [`Result`].
     pub fn as_deref_mut_err(&mut self) -> Result<&mut T, &mut E::Target> {
         self.as_mut().map_err(|e| e.deref_mut())
     }
diff --git a/src/libcore/tests/array.rs b/src/libcore/tests/array.rs
index c2a816f0a7d90..4bc44e98fc802 100644
--- a/src/libcore/tests/array.rs
+++ b/src/libcore/tests/array.rs
@@ -241,3 +241,52 @@ fn iterator_drops() {
     }
     assert_eq!(i.get(), 5);
 }
+
+// This test does not work on targets without panic=unwind support.
+// To work around this problem, test is marked is should_panic, so it will
+// be automagically skipped on unsuitable targets, such as
+// wasm32-unknown-unkown.
+//
+// It means that we use panic for indicating success.
+#[test]
+#[should_panic(expected = "test succeeded")]
+fn array_default_impl_avoids_leaks_on_panic() {
+    use core::sync::atomic::{AtomicUsize, Ordering::Relaxed};
+    static COUNTER: AtomicUsize = AtomicUsize::new(0);
+    #[derive(Debug)]
+    struct Bomb(usize);
+
+    impl Default for Bomb {
+        fn default() -> Bomb {
+            if COUNTER.load(Relaxed) == 3 {
+                panic!("bomb limit exceeded");
+            }
+
+            COUNTER.fetch_add(1, Relaxed);
+            Bomb(COUNTER.load(Relaxed))
+        }
+    }
+
+    impl Drop for Bomb {
+        fn drop(&mut self) {
+            COUNTER.fetch_sub(1, Relaxed);
+        }
+    }
+
+    let res = std::panic::catch_unwind(|| <[Bomb; 5]>::default());
+    let panic_msg = match res {
+        Ok(_) => unreachable!(),
+        Err(p) => p.downcast::<&'static str>().unwrap(),
+    };
+    assert_eq!(*panic_msg, "bomb limit exceeded");
+    // check that all bombs are successfully dropped
+    assert_eq!(COUNTER.load(Relaxed), 0);
+    panic!("test succeeded")
+}
+
+#[test]
+fn empty_array_is_always_default() {
+    struct DoesNotImplDefault;
+
+    let _arr = <[DoesNotImplDefault; 0]>::default();
+}
diff --git a/src/librustc_ast/ast.rs b/src/librustc_ast/ast.rs
index 62406552e318f..ce186c4834d72 100644
--- a/src/librustc_ast/ast.rs
+++ b/src/librustc_ast/ast.rs
@@ -5,7 +5,7 @@
 //! additional metadata), and [`ItemKind`] (which represents a concrete type and contains
 //! information specific to the type of the item).
 //!
-//! Other module items that worth mentioning:
+//! Other module items worth mentioning:
 //! - [`Ty`] and [`TyKind`]: A parsed Rust type.
 //! - [`Expr`] and [`ExprKind`]: A parsed Rust expression.
 //! - [`Pat`] and [`PatKind`]: A parsed Rust pattern. Patterns are often dual to expressions.
diff --git a/src/librustc_codegen_ssa/back/symbol_export.rs b/src/librustc_codegen_ssa/back/symbol_export.rs
index 970d13b30c04e..98f7da8361cc4 100644
--- a/src/librustc_codegen_ssa/back/symbol_export.rs
+++ b/src/librustc_codegen_ssa/back/symbol_export.rs
@@ -89,10 +89,12 @@ fn reachable_non_generics_provider(tcx: TyCtxt<'_>, cnum: CrateNum) -> DefIdMap<
                 | Node::ImplItem(&hir::ImplItem { kind: hir::ImplItemKind::Fn(..), .. }) => {
                     let def_id = tcx.hir().local_def_id(hir_id);
                     let generics = tcx.generics_of(def_id);
-                    if !generics.requires_monomorphization(tcx) &&
-                        // Functions marked with #[inline] are only ever codegened
-                        // with "internal" linkage and are never exported.
-                        !Instance::mono(tcx, def_id.to_def_id()).def.generates_cgu_internal_copy(tcx)
+                    if !generics.requires_monomorphization(tcx)
+                        // Functions marked with #[inline] are codegened with "internal"
+                        // linkage and are not exported unless marked with an extern
+                        // inidicator
+                        && (!Instance::mono(tcx, def_id.to_def_id()).def.generates_cgu_internal_copy(tcx)
+                            || tcx.codegen_fn_attrs(def_id.to_def_id()).contains_extern_indicator())
                     {
                         Some(def_id)
                     } else {
diff --git a/src/librustc_codegen_ssa/debuginfo/type_names.rs b/src/librustc_codegen_ssa/debuginfo/type_names.rs
index 57a3d8b5edcaf..a64489c04c81d 100644
--- a/src/librustc_codegen_ssa/debuginfo/type_names.rs
+++ b/src/librustc_codegen_ssa/debuginfo/type_names.rs
@@ -195,7 +195,7 @@ pub fn push_debuginfo_type_name<'tcx>(
                 tcx.def_key(def_id).disambiguated_data.disambiguator
             ));
         }
-        ty::Error
+        ty::Error(_)
         | ty::Infer(_)
         | ty::Placeholder(..)
         | ty::Projection(..)
diff --git a/src/librustc_codegen_ssa/mir/analyze.rs b/src/librustc_codegen_ssa/mir/analyze.rs
index 61692280d2a77..db935c2b3e265 100644
--- a/src/librustc_codegen_ssa/mir/analyze.rs
+++ b/src/librustc_codegen_ssa/mir/analyze.rs
@@ -234,8 +234,8 @@ impl<'mir, 'a, 'tcx, Bx: BuilderMethods<'a, 'tcx>> Visitor<'tcx>
         self.visit_rvalue(rvalue, location);
     }
 
-    fn visit_terminator_kind(&mut self, kind: &mir::TerminatorKind<'tcx>, location: Location) {
-        let check = match *kind {
+    fn visit_terminator(&mut self, terminator: &mir::Terminator<'tcx>, location: Location) {
+        let check = match terminator.kind {
             mir::TerminatorKind::Call { func: mir::Operand::Constant(ref c), ref args, .. } => {
                 match c.literal.ty.kind {
                     ty::FnDef(did, _) => Some((did, args)),
@@ -259,7 +259,7 @@ impl<'mir, 'a, 'tcx, Bx: BuilderMethods<'a, 'tcx>> Visitor<'tcx>
             }
         }
 
-        self.super_terminator_kind(kind, location);
+        self.super_terminator(terminator, location);
     }
 
     fn visit_place(&mut self, place: &mir::Place<'tcx>, context: PlaceContext, location: Location) {
diff --git a/src/librustc_codegen_ssa/mir/block.rs b/src/librustc_codegen_ssa/mir/block.rs
index ef59ad486eefe..c486d5c64baa2 100644
--- a/src/librustc_codegen_ssa/mir/block.rs
+++ b/src/librustc_codegen_ssa/mir/block.rs
@@ -998,8 +998,8 @@ impl<'a, 'tcx, Bx: BuilderMethods<'a, 'tcx>> FunctionCx<'a, 'tcx, Bx> {
                 bx.unreachable();
             }
 
-            mir::TerminatorKind::Drop { location, target, unwind } => {
-                self.codegen_drop_terminator(helper, bx, location, target, unwind);
+            mir::TerminatorKind::Drop { place, target, unwind } => {
+                self.codegen_drop_terminator(helper, bx, place, target, unwind);
             }
 
             mir::TerminatorKind::Assert { ref cond, expected, ref msg, target, cleanup } => {
diff --git a/src/librustc_error_codes/error_codes.rs b/src/librustc_error_codes/error_codes.rs
index 3fb5e04efc922..99ef226f94aae 100644
--- a/src/librustc_error_codes/error_codes.rs
+++ b/src/librustc_error_codes/error_codes.rs
@@ -439,6 +439,7 @@ E0752: include_str!("./error_codes/E0752.md"),
 E0753: include_str!("./error_codes/E0753.md"),
 E0754: include_str!("./error_codes/E0754.md"),
 E0758: include_str!("./error_codes/E0758.md"),
+E0759: include_str!("./error_codes/E0759.md"),
 E0760: include_str!("./error_codes/E0760.md"),
 E0761: include_str!("./error_codes/E0761.md"),
 E0762: include_str!("./error_codes/E0762.md"),
diff --git a/src/librustc_error_codes/error_codes/E0759.md b/src/librustc_error_codes/error_codes/E0759.md
new file mode 100644
index 0000000000000..a74759bdf634b
--- /dev/null
+++ b/src/librustc_error_codes/error_codes/E0759.md
@@ -0,0 +1,67 @@
+A `'static` requirement in a return type involving a trait is not fulfilled.
+
+Erroneous code examples:
+
+```compile_fail,E0759
+use std::fmt::Debug;
+
+fn foo(x: &i32) -> impl Debug {
+    x
+}
+```
+
+```compile_fail,E0759
+# use std::fmt::Debug;
+fn bar(x: &i32) -> Box<dyn Debug> {
+    Box::new(x)
+}
+```
+
+These examples have the same semantics as the following:
+
+```compile_fail,E0759
+# use std::fmt::Debug;
+fn foo(x: &i32) -> impl Debug + 'static {
+    x
+}
+```
+
+```compile_fail,E0759
+# use std::fmt::Debug;
+fn bar(x: &i32) -> Box<dyn Debug + 'static> {
+    Box::new(x)
+}
+```
+
+Both [`dyn Trait`] and [`impl Trait`] in return types have a an implicit
+`'static` requirement, meaning that the value implementing them that is being
+returned has to be either a `'static` borrow or an owned value.
+
+In order to change the requirement from `'static` to be a lifetime derived from
+its arguments, you can add an explicit bound, either to an anonymous lifetime
+`'_` or some appropriate named lifetime.
+
+```
+# use std::fmt::Debug;
+fn foo(x: &i32) -> impl Debug + '_ {
+    x
+}
+fn bar(x: &i32) -> Box<dyn Debug + '_> {
+    Box::new(x)
+}
+```
+
+These are equivalent to the following explicit lifetime annotations:
+
+```
+# use std::fmt::Debug;
+fn foo<'a>(x: &'a i32) -> impl Debug + 'a {
+    x
+}
+fn bar<'a>(x: &'a i32) -> Box<dyn Debug + 'a> {
+    Box::new(x)
+}
+```
+
+[`dyn Trait`]: https://doc.rust-lang.org/book/ch17-02-trait-objects.html#using-trait-objects-that-allow-for-values-of-different-types
+[`impl Trait`]: https://doc.rust-lang.org/book/ch10-02-traits.html#returning-types-that-implement-traits
diff --git a/src/librustc_errors/lib.rs b/src/librustc_errors/lib.rs
index 7261c638ce013..0c1418d3cad27 100644
--- a/src/librustc_errors/lib.rs
+++ b/src/librustc_errors/lib.rs
@@ -5,6 +5,7 @@
 #![doc(html_root_url = "https://doc.rust-lang.org/nightly/")]
 #![feature(crate_visibility_modifier)]
 #![feature(nll)]
+#![feature(track_caller)]
 
 pub use emitter::ColorConfig;
 
@@ -621,6 +622,7 @@ impl Handler {
         self.inner.borrow_mut().span_bug(span, msg)
     }
 
+    #[track_caller]
     pub fn delay_span_bug(&self, span: impl Into<MultiSpan>, msg: &str) {
         self.inner.borrow_mut().delay_span_bug(span, msg)
     }
@@ -873,6 +875,7 @@ impl HandlerInner {
         self.emit_diagnostic(diag.set_span(sp));
     }
 
+    #[track_caller]
     fn delay_span_bug(&mut self, sp: impl Into<MultiSpan>, msg: &str) {
         // This is technically `self.treat_err_as_bug()` but `delay_span_bug` is called before
         // incrementing `err_count` by one, so we need to +1 the comparing.
@@ -883,6 +886,7 @@ impl HandlerInner {
         }
         let mut diagnostic = Diagnostic::new(Level::Bug, msg);
         diagnostic.set_span(sp.into());
+        diagnostic.note(&format!("delayed at {}", std::panic::Location::caller()));
         self.delay_as_bug(diagnostic)
     }
 
diff --git a/src/librustc_hir/hir.rs b/src/librustc_hir/hir.rs
index 634ab32a28542..bed2044c70855 100644
--- a/src/librustc_hir/hir.rs
+++ b/src/librustc_hir/hir.rs
@@ -2726,6 +2726,18 @@ impl Node<'_> {
         }
     }
 
+    pub fn body_id(&self) -> Option<BodyId> {
+        match self {
+            Node::TraitItem(TraitItem {
+                kind: TraitItemKind::Fn(_, TraitFn::Provided(body_id)),
+                ..
+            })
+            | Node::ImplItem(ImplItem { kind: ImplItemKind::Fn(_, body_id), .. })
+            | Node::Item(Item { kind: ItemKind::Fn(.., body_id), .. }) => Some(*body_id),
+            _ => None,
+        }
+    }
+
     pub fn generics(&self) -> Option<&Generics<'_>> {
         match self {
             Node::TraitItem(TraitItem { generics, .. })
diff --git a/src/librustc_infer/infer/canonical/canonicalizer.rs b/src/librustc_infer/infer/canonical/canonicalizer.rs
index c2dae6ba4f83d..427cc55a428ae 100644
--- a/src/librustc_infer/infer/canonical/canonicalizer.rs
+++ b/src/librustc_infer/infer/canonical/canonicalizer.rs
@@ -403,7 +403,7 @@ impl<'cx, 'tcx> TypeFolder<'tcx> for Canonicalizer<'cx, 'tcx> {
             | ty::Float(..)
             | ty::Adt(..)
             | ty::Str
-            | ty::Error
+            | ty::Error(_)
             | ty::Array(..)
             | ty::Slice(..)
             | ty::RawPtr(..)
diff --git a/src/librustc_infer/infer/canonical/mod.rs b/src/librustc_infer/infer/canonical/mod.rs
index 7310d2c3bdcf8..2b8c46f1de42d 100644
--- a/src/librustc_infer/infer/canonical/mod.rs
+++ b/src/librustc_infer/infer/canonical/mod.rs
@@ -154,7 +154,7 @@ impl<'cx, 'tcx> InferCtxt<'cx, 'tcx> {
                 self.tcx
                     .mk_const(ty::Const {
                         val: ty::ConstKind::Placeholder(placeholder_mapped),
-                        ty: self.tcx.types.err, // FIXME(const_generics)
+                        ty: self.tcx.ty_error(), // FIXME(const_generics)
                     })
                     .into()
             }
diff --git a/src/librustc_infer/infer/error_reporting/mod.rs b/src/librustc_infer/infer/error_reporting/mod.rs
index 12f7a9c0ca502..9cfa11dd7c813 100644
--- a/src/librustc_infer/infer/error_reporting/mod.rs
+++ b/src/librustc_infer/infer/error_reporting/mod.rs
@@ -2035,8 +2035,7 @@ impl<'a, 'tcx> InferCtxt<'a, 'tcx> {
             self.tcx.sess,
             var_origin.span(),
             E0495,
-            "cannot infer an appropriate lifetime{} \
-             due to conflicting requirements",
+            "cannot infer an appropriate lifetime{} due to conflicting requirements",
             var_description
         )
     }
diff --git a/src/librustc_infer/infer/error_reporting/nice_region_error/static_impl_trait.rs b/src/librustc_infer/infer/error_reporting/nice_region_error/static_impl_trait.rs
index f4c86ddae604e..82feebc80292a 100644
--- a/src/librustc_infer/infer/error_reporting/nice_region_error/static_impl_trait.rs
+++ b/src/librustc_infer/infer/error_reporting/nice_region_error/static_impl_trait.rs
@@ -1,14 +1,15 @@
 //! Error Reporting for static impl Traits.
 
-use crate::infer::error_reporting::msg_span_from_free_region;
 use crate::infer::error_reporting::nice_region_error::NiceRegionError;
 use crate::infer::lexical_region_resolve::RegionResolutionError;
-use rustc_errors::{Applicability, ErrorReported};
+use rustc_errors::{struct_span_err, Applicability, ErrorReported};
+use rustc_hir::{GenericBound, ItemKind, Lifetime, LifetimeName, TyKind};
 use rustc_middle::ty::RegionKind;
 
 impl<'a, 'tcx> NiceRegionError<'a, 'tcx> {
     /// Print the error message for lifetime errors when the return type is a static impl Trait.
     pub(super) fn try_report_static_impl_trait(&self) -> Option<ErrorReported> {
+        debug!("try_report_static_impl_trait(error={:?})", self.error);
         if let Some(ref error) = self.error {
             if let RegionResolutionError::SubSupConflict(
                 _,
@@ -17,18 +18,36 @@ impl<'a, 'tcx> NiceRegionError<'a, 'tcx> {
                 sub_r,
                 sup_origin,
                 sup_r,
-            ) = error.clone()
+            ) = error
             {
+                debug!(
+                    "try_report_static_impl_trait(var={:?}, sub={:?} {:?} sup={:?} {:?})",
+                    var_origin, sub_origin, sub_r, sup_origin, sup_r
+                );
                 let anon_reg_sup = self.tcx().is_suitable_region(sup_r)?;
-                let (fn_return_span, is_dyn) =
-                    self.tcx().return_type_impl_or_dyn_trait(anon_reg_sup.def_id)?;
-                if sub_r == &RegionKind::ReStatic {
+                debug!("try_report_static_impl_trait: anon_reg_sup={:?}", anon_reg_sup);
+                let fn_return = self.tcx().return_type_impl_or_dyn_trait(anon_reg_sup.def_id)?;
+                debug!("try_report_static_impl_trait: fn_return={:?}", fn_return);
+                if **sub_r == RegionKind::ReStatic {
                     let sp = var_origin.span();
                     let return_sp = sub_origin.span();
-                    let mut err =
-                        self.tcx().sess.struct_span_err(sp, "cannot infer an appropriate lifetime");
                     let param_info = self.find_param_with_region(sup_r, sub_r)?;
-                    err.span_label(param_info.param_ty_span, "data with this lifetime...");
+                    let (lifetime_name, lifetime) = if sup_r.has_name() {
+                        (sup_r.to_string(), format!("lifetime `{}`", sup_r))
+                    } else {
+                        ("'_".to_owned(), "an anonymous lifetime `'_`".to_string())
+                    };
+                    let mut err = struct_span_err!(
+                        self.tcx().sess,
+                        sp,
+                        E0759,
+                        "cannot infer an appropriate lifetime"
+                    );
+                    err.span_label(
+                        param_info.param_ty_span,
+                        &format!("this data with {}...", lifetime),
+                    );
+                    debug!("try_report_static_impl_trait: param_info={:?}", param_info);
 
                     // We try to make the output have fewer overlapping spans if possible.
                     if (sp == sup_origin.span() || !return_sp.overlaps(sup_origin.span()))
@@ -38,41 +57,146 @@ impl<'a, 'tcx> NiceRegionError<'a, 'tcx> {
 
                         // Customize the spans and labels depending on their relative order so
                         // that split sentences flow correctly.
-                        if sup_origin.span().shrink_to_hi() <= return_sp.shrink_to_lo() {
-                            err.span_label(sup_origin.span(), "...is captured here...");
-                            err.span_label(return_sp, "...and required to be `'static` by this");
+                        if sup_origin.span().overlaps(return_sp) && sp == sup_origin.span() {
+                            // Avoid the following:
+                            //
+                            // error: cannot infer an appropriate lifetime
+                            //   --> $DIR/must_outlive_least_region_or_bound.rs:18:50
+                            //    |
+                            // LL | fn foo(x: &i32) -> Box<dyn Debug> { Box::new(x) }
+                            //    |           ----                      ---------^-
+                            //
+                            // and instead show:
+                            //
+                            // error: cannot infer an appropriate lifetime
+                            //   --> $DIR/must_outlive_least_region_or_bound.rs:18:50
+                            //    |
+                            // LL | fn foo(x: &i32) -> Box<dyn Debug> { Box::new(x) }
+                            //    |           ----                               ^
+                            err.span_label(
+                                sup_origin.span(),
+                                "...is captured here, requiring it to live as long as `'static`",
+                            );
                         } else {
-                            err.span_label(return_sp, "...is required to be `'static` by this...");
-                            err.span_label(sup_origin.span(), "...and is captured here");
+                            err.span_label(sup_origin.span(), "...is captured here...");
+                            if return_sp < sup_origin.span() {
+                                err.span_note(
+                                    return_sp,
+                                    "...and is required to live as long as `'static` here",
+                                );
+                            } else {
+                                err.span_label(
+                                    return_sp,
+                                    "...and is required to live as long as `'static` here",
+                                );
+                            }
                         }
                     } else {
                         err.span_label(
                             return_sp,
-                            "...is captured and required to be `'static` here",
+                            "...is captured and required to live as long as `'static` here",
                         );
                     }
 
-                    let (lifetime, _) = msg_span_from_free_region(self.tcx(), sup_r);
-
-                    let lifetime_name =
-                        if sup_r.has_name() { sup_r.to_string() } else { "'_".to_owned() };
                     // only apply this suggestion onto functions with
                     // explicit non-desugar'able return.
-                    if fn_return_span.desugaring_kind().is_none() {
-                        let msg = format!(
-                            "to permit non-static references in {} `{} Trait` value, you can add \
-                             an explicit bound for {}",
-                            if is_dyn { "a" } else { "an" },
-                            if is_dyn { "dyn" } else { "impl" },
-                            lifetime,
-                        );
+                    if fn_return.span.desugaring_kind().is_none() {
                         // FIXME: account for the need of parens in `&(dyn Trait + '_)`
-                        err.span_suggestion_verbose(
-                            fn_return_span.shrink_to_hi(),
-                            &msg,
-                            format!(" + {}", lifetime_name),
-                            Applicability::MaybeIncorrect,
-                        );
+
+                        let consider = "consider changing the";
+                        let declare = "to declare that the";
+                        let arg = match param_info.param.pat.simple_ident() {
+                            Some(simple_ident) => format!("argument `{}`", simple_ident),
+                            None => "the argument".to_string(),
+                        };
+                        let explicit =
+                            format!("you can add an explicit `{}` lifetime bound", lifetime_name);
+                        let explicit_static =
+                            format!("explicit `'static` bound to the lifetime of {}", arg);
+                        let captures = format!("captures data from {}", arg);
+                        let add_static_bound =
+                            "alternatively, add an explicit `'static` bound to this reference";
+                        let plus_lt = format!(" + {}", lifetime_name);
+                        match fn_return.kind {
+                            TyKind::OpaqueDef(item_id, _) => {
+                                let item = self.tcx().hir().item(item_id.id);
+                                let opaque = if let ItemKind::OpaqueTy(opaque) = &item.kind {
+                                    opaque
+                                } else {
+                                    err.emit();
+                                    return Some(ErrorReported);
+                                };
+
+                                if let Some(span) = opaque
+                                    .bounds
+                                    .iter()
+                                    .filter_map(|arg| match arg {
+                                        GenericBound::Outlives(Lifetime {
+                                            name: LifetimeName::Static,
+                                            span,
+                                            ..
+                                        }) => Some(*span),
+                                        _ => None,
+                                    })
+                                    .next()
+                                {
+                                    err.span_suggestion_verbose(
+                                        span,
+                                        &format!("{} `impl Trait`'s {}", consider, explicit_static),
+                                        lifetime_name,
+                                        Applicability::MaybeIncorrect,
+                                    );
+                                    err.span_suggestion_verbose(
+                                        param_info.param_ty_span,
+                                        add_static_bound,
+                                        param_info.param_ty.to_string(),
+                                        Applicability::MaybeIncorrect,
+                                    );
+                                } else {
+                                    err.span_suggestion_verbose(
+                                        fn_return.span.shrink_to_hi(),
+                                        &format!(
+                                            "{declare} `impl Trait` {captures}, {explicit}",
+                                            declare = declare,
+                                            captures = captures,
+                                            explicit = explicit,
+                                        ),
+                                        plus_lt,
+                                        Applicability::MaybeIncorrect,
+                                    );
+                                };
+                            }
+                            TyKind::TraitObject(_, lt) => match lt.name {
+                                LifetimeName::ImplicitObjectLifetimeDefault => {
+                                    err.span_suggestion_verbose(
+                                        fn_return.span.shrink_to_hi(),
+                                        &format!(
+                                            "{declare} trait object {captures}, {explicit}",
+                                            declare = declare,
+                                            captures = captures,
+                                            explicit = explicit,
+                                        ),
+                                        plus_lt,
+                                        Applicability::MaybeIncorrect,
+                                    );
+                                }
+                                _ => {
+                                    err.span_suggestion_verbose(
+                                        lt.span,
+                                        &format!("{} trait object's {}", consider, explicit_static),
+                                        lifetime_name,
+                                        Applicability::MaybeIncorrect,
+                                    );
+                                    err.span_suggestion_verbose(
+                                        param_info.param_ty_span,
+                                        add_static_bound,
+                                        param_info.param_ty.to_string(),
+                                        Applicability::MaybeIncorrect,
+                                    );
+                                }
+                            },
+                            _ => {}
+                        }
                     }
                     err.emit();
                     return Some(ErrorReported);
diff --git a/src/librustc_infer/infer/freshen.rs b/src/librustc_infer/infer/freshen.rs
index b4cfcb3a1c325..02bebe10ed04a 100644
--- a/src/librustc_infer/infer/freshen.rs
+++ b/src/librustc_infer/infer/freshen.rs
@@ -192,7 +192,7 @@ impl<'a, 'tcx> TypeFolder<'tcx> for TypeFreshener<'a, 'tcx> {
             | ty::Float(..)
             | ty::Adt(..)
             | ty::Str
-            | ty::Error
+            | ty::Error(_)
             | ty::Array(..)
             | ty::Slice(..)
             | ty::RawPtr(..)
@@ -250,7 +250,7 @@ impl<'a, 'tcx> TypeFolder<'tcx> for TypeFreshener<'a, 'tcx> {
             ty::ConstKind::Param(_)
             | ty::ConstKind::Value(_)
             | ty::ConstKind::Unevaluated(..)
-            | ty::ConstKind::Error => {}
+            | ty::ConstKind::Error(_) => {}
         }
 
         ct.super_fold_with(self)
diff --git a/src/librustc_infer/infer/mod.rs b/src/librustc_infer/infer/mod.rs
index 92387f753f55e..91f4b3323f30e 100644
--- a/src/librustc_infer/infer/mod.rs
+++ b/src/librustc_infer/infer/mod.rs
@@ -1751,9 +1751,10 @@ impl<'tcx> TypeTrace<'tcx> {
     }
 
     pub fn dummy(tcx: TyCtxt<'tcx>) -> TypeTrace<'tcx> {
+        let err = tcx.ty_error();
         TypeTrace {
             cause: ObligationCause::dummy(),
-            values: Types(ExpectedFound { expected: tcx.types.err, found: tcx.types.err }),
+            values: Types(ExpectedFound { expected: err, found: err }),
         }
     }
 }
diff --git a/src/librustc_infer/infer/resolve.rs b/src/librustc_infer/infer/resolve.rs
index e28cf49c7f253..df166d21a36c3 100644
--- a/src/librustc_infer/infer/resolve.rs
+++ b/src/librustc_infer/infer/resolve.rs
@@ -189,15 +189,15 @@ impl<'a, 'tcx> TypeFolder<'tcx> for FullTypeResolver<'a, 'tcx> {
             match t.kind {
                 ty::Infer(ty::TyVar(vid)) => {
                     self.err = Some(FixupError::UnresolvedTy(vid));
-                    self.tcx().types.err
+                    self.tcx().ty_error()
                 }
                 ty::Infer(ty::IntVar(vid)) => {
                     self.err = Some(FixupError::UnresolvedIntTy(vid));
-                    self.tcx().types.err
+                    self.tcx().ty_error()
                 }
                 ty::Infer(ty::FloatVar(vid)) => {
                     self.err = Some(FixupError::UnresolvedFloatTy(vid));
-                    self.tcx().types.err
+                    self.tcx().ty_error()
                 }
                 ty::Infer(_) => {
                     bug!("Unexpected type in full type resolver: {:?}", t);
@@ -228,7 +228,7 @@ impl<'a, 'tcx> TypeFolder<'tcx> for FullTypeResolver<'a, 'tcx> {
             match c.val {
                 ty::ConstKind::Infer(InferConst::Var(vid)) => {
                     self.err = Some(FixupError::UnresolvedConst(vid));
-                    return self.tcx().mk_const(ty::Const { val: ty::ConstKind::Error, ty: c.ty });
+                    return self.tcx().const_error(c.ty);
                 }
                 ty::ConstKind::Infer(InferConst::Fresh(_)) => {
                     bug!("Unexpected const in full const resolver: {:?}", c);
diff --git a/src/librustc_infer/infer/sub.rs b/src/librustc_infer/infer/sub.rs
index b51af19883fdd..90962d210b5b4 100644
--- a/src/librustc_infer/infer/sub.rs
+++ b/src/librustc_infer/infer/sub.rs
@@ -119,9 +119,9 @@ impl TypeRelation<'tcx> for Sub<'combine, 'infcx, 'tcx> {
                 Ok(a)
             }
 
-            (&ty::Error, _) | (_, &ty::Error) => {
+            (&ty::Error(_), _) | (_, &ty::Error(_)) => {
                 infcx.set_tainted_by_errors();
-                Ok(self.tcx().types.err)
+                Ok(self.tcx().ty_error())
             }
 
             _ => {
diff --git a/src/librustc_lint/types.rs b/src/librustc_lint/types.rs
index a8ecfdd0f3d45..1dd6d837d4eaf 100644
--- a/src/librustc_lint/types.rs
+++ b/src/librustc_lint/types.rs
@@ -889,7 +889,7 @@ impl<'a, 'tcx> ImproperCTypesVisitor<'a, 'tcx> {
             ty::Param(..)
             | ty::Infer(..)
             | ty::Bound(..)
-            | ty::Error
+            | ty::Error(_)
             | ty::Closure(..)
             | ty::Generator(..)
             | ty::GeneratorWitness(..)
diff --git a/src/librustc_middle/mir/mod.rs b/src/librustc_middle/mir/mod.rs
index 27848684706d6..f281c13517663 100644
--- a/src/librustc_middle/mir/mod.rs
+++ b/src/librustc_middle/mir/mod.rs
@@ -1112,7 +1112,7 @@ pub enum TerminatorKind<'tcx> {
     Unreachable,
 
     /// Drop the `Place`.
-    Drop { location: Place<'tcx>, target: BasicBlock, unwind: Option<BasicBlock> },
+    Drop { place: Place<'tcx>, target: BasicBlock, unwind: Option<BasicBlock> },
 
     /// Drop the `Place` and assign the new value over it. This ensures
     /// that the assignment to `P` occurs *even if* the destructor for
@@ -1141,7 +1141,7 @@ pub enum TerminatorKind<'tcx> {
     /// }
     /// ```
     DropAndReplace {
-        location: Place<'tcx>,
+        place: Place<'tcx>,
         value: Operand<'tcx>,
         target: BasicBlock,
         unwind: Option<BasicBlock>,
@@ -1607,9 +1607,9 @@ impl<'tcx> TerminatorKind<'tcx> {
             Abort => write!(fmt, "abort"),
             Yield { value, resume_arg, .. } => write!(fmt, "{:?} = yield({:?})", resume_arg, value),
             Unreachable => write!(fmt, "unreachable"),
-            Drop { location, .. } => write!(fmt, "drop({:?})", location),
-            DropAndReplace { location, value, .. } => {
-                write!(fmt, "replace({:?} <- {:?})", location, value)
+            Drop { place, .. } => write!(fmt, "drop({:?})", place),
+            DropAndReplace { place, value, .. } => {
+                write!(fmt, "replace({:?} <- {:?})", place, value)
             }
             Call { func, args, destination, .. } => {
                 if let Some((destination, _)) = destination {
diff --git a/src/librustc_middle/mir/mono.rs b/src/librustc_middle/mir/mono.rs
index c889dbc0a4498..f1c1b962ab997 100644
--- a/src/librustc_middle/mir/mono.rs
+++ b/src/librustc_middle/mir/mono.rs
@@ -91,9 +91,9 @@ impl<'tcx> MonoItem<'tcx> {
         match *self {
             MonoItem::Fn(ref instance) => {
                 let entry_def_id = tcx.entry_fn(LOCAL_CRATE).map(|(id, _)| id);
-                // If this function isn't inlined or otherwise has explicit
-                // linkage, then we'll be creating a globally shared version.
-                if self.explicit_linkage(tcx).is_some()
+                // If this function isn't inlined or otherwise has an extern
+                // indicator, then we'll be creating a globally shared version.
+                if tcx.codegen_fn_attrs(instance.def_id()).contains_extern_indicator()
                     || !instance.def.generates_cgu_internal_copy(tcx)
                     || Some(instance.def_id()) == entry_def_id.map(LocalDefId::to_def_id)
                 {
@@ -102,7 +102,7 @@ impl<'tcx> MonoItem<'tcx> {
 
                 // At this point we don't have explicit linkage and we're an
                 // inlined function. If we're inlining into all CGUs then we'll
-                // be creating a local copy per CGU
+                // be creating a local copy per CGU.
                 if generate_cgu_internal_copies {
                     return InstantiationMode::LocalCopy;
                 }
diff --git a/src/librustc_middle/mir/type_foldable.rs b/src/librustc_middle/mir/type_foldable.rs
index 3f5d528d9e7c4..89f8f10449e2d 100644
--- a/src/librustc_middle/mir/type_foldable.rs
+++ b/src/librustc_middle/mir/type_foldable.rs
@@ -27,11 +27,11 @@ impl<'tcx> TypeFoldable<'tcx> for Terminator<'tcx> {
                 values: values.clone(),
                 targets: targets.clone(),
             },
-            Drop { ref location, target, unwind } => {
-                Drop { location: location.fold_with(folder), target, unwind }
+            Drop { ref place, target, unwind } => {
+                Drop { place: place.fold_with(folder), target, unwind }
             }
-            DropAndReplace { ref location, ref value, target, unwind } => DropAndReplace {
-                location: location.fold_with(folder),
+            DropAndReplace { ref place, ref value, target, unwind } => DropAndReplace {
+                place: place.fold_with(folder),
                 value: value.fold_with(folder),
                 target,
                 unwind,
@@ -97,9 +97,9 @@ impl<'tcx> TypeFoldable<'tcx> for Terminator<'tcx> {
             SwitchInt { ref discr, switch_ty, .. } => {
                 discr.visit_with(visitor) || switch_ty.visit_with(visitor)
             }
-            Drop { ref location, .. } => location.visit_with(visitor),
-            DropAndReplace { ref location, ref value, .. } => {
-                location.visit_with(visitor) || value.visit_with(visitor)
+            Drop { ref place, .. } => place.visit_with(visitor),
+            DropAndReplace { ref place, ref value, .. } => {
+                place.visit_with(visitor) || value.visit_with(visitor)
             }
             Yield { ref value, .. } => value.visit_with(visitor),
             Call { ref func, ref args, ref destination, .. } => {
diff --git a/src/librustc_middle/mir/visit.rs b/src/librustc_middle/mir/visit.rs
index 5f9fcdca516b1..2efc5f1dabedc 100644
--- a/src/librustc_middle/mir/visit.rs
+++ b/src/librustc_middle/mir/visit.rs
@@ -108,12 +108,6 @@ macro_rules! make_mir_visitor {
                 self.super_terminator(terminator, location);
             }
 
-            fn visit_terminator_kind(&mut self,
-                                     kind: & $($mutability)? TerminatorKind<'tcx>,
-                                     location: Location) {
-                self.super_terminator_kind(kind, location);
-            }
-
             fn visit_assert_message(&mut self,
                                     msg: & $($mutability)? AssertMessage<'tcx>,
                                     location: Location) {
@@ -417,12 +411,6 @@ macro_rules! make_mir_visitor {
                 let Terminator { source_info, kind } = terminator;
 
                 self.visit_source_info(source_info);
-                self.visit_terminator_kind(kind, location);
-            }
-
-            fn super_terminator_kind(&mut self,
-                                     kind: & $($mutability)? TerminatorKind<'tcx>,
-                                     source_location: Location) {
                 match kind {
                     TerminatorKind::Goto { .. } |
                     TerminatorKind::Resume |
@@ -440,7 +428,7 @@ macro_rules! make_mir_visitor {
                         self.visit_local(
                             & $($mutability)? local,
                             PlaceContext::NonMutatingUse(NonMutatingUseContext::Move),
-                            source_location,
+                            location,
                         );
 
                         assert_eq!(
@@ -456,34 +444,34 @@ macro_rules! make_mir_visitor {
                         values: _,
                         targets: _
                     } => {
-                        self.visit_operand(discr, source_location);
-                        self.visit_ty(switch_ty, TyContext::Location(source_location));
+                        self.visit_operand(discr, location);
+                        self.visit_ty(switch_ty, TyContext::Location(location));
                     }
 
                     TerminatorKind::Drop {
-                        location,
+                        place,
                         target: _,
                         unwind: _,
                     } => {
                         self.visit_place(
-                            location,
+                            place,
                             PlaceContext::MutatingUse(MutatingUseContext::Drop),
-                            source_location
+                            location
                         );
                     }
 
                     TerminatorKind::DropAndReplace {
-                        location,
+                        place,
                         value,
                         target: _,
                         unwind: _,
                     } => {
                         self.visit_place(
-                            location,
+                            place,
                             PlaceContext::MutatingUse(MutatingUseContext::Drop),
-                            source_location
+                            location
                         );
-                        self.visit_operand(value, source_location);
+                        self.visit_operand(value, location);
                     }
 
                     TerminatorKind::Call {
@@ -494,15 +482,15 @@ macro_rules! make_mir_visitor {
                         from_hir_call: _,
                         fn_span: _
                     } => {
-                        self.visit_operand(func, source_location);
+                        self.visit_operand(func, location);
                         for arg in args {
-                            self.visit_operand(arg, source_location);
+                            self.visit_operand(arg, location);
                         }
                         if let Some((destination, _)) = destination {
                             self.visit_place(
                                 destination,
                                 PlaceContext::MutatingUse(MutatingUseContext::Call),
-                                source_location
+                                location
                             );
                         }
                     }
@@ -514,8 +502,8 @@ macro_rules! make_mir_visitor {
                         target: _,
                         cleanup: _,
                     } => {
-                        self.visit_operand(cond, source_location);
-                        self.visit_assert_message(msg, source_location);
+                        self.visit_operand(cond, location);
+                        self.visit_assert_message(msg, location);
                     }
 
                     TerminatorKind::Yield {
@@ -524,11 +512,11 @@ macro_rules! make_mir_visitor {
                         resume_arg,
                         drop: _,
                     } => {
-                        self.visit_operand(value, source_location);
+                        self.visit_operand(value, location);
                         self.visit_place(
                             resume_arg,
                             PlaceContext::MutatingUse(MutatingUseContext::Yield),
-                            source_location,
+                            location,
                         );
                     }
 
@@ -543,29 +531,29 @@ macro_rules! make_mir_visitor {
                             match op {
                                 InlineAsmOperand::In { value, .. }
                                 | InlineAsmOperand::Const { value } => {
-                                    self.visit_operand(value, source_location);
+                                    self.visit_operand(value, location);
                                 }
                                 InlineAsmOperand::Out { place, .. } => {
                                     if let Some(place) = place {
                                         self.visit_place(
                                             place,
                                             PlaceContext::MutatingUse(MutatingUseContext::Store),
-                                            source_location,
+                                            location,
                                         );
                                     }
                                 }
                                 InlineAsmOperand::InOut { in_value, out_place, .. } => {
-                                    self.visit_operand(in_value, source_location);
+                                    self.visit_operand(in_value, location);
                                     if let Some(out_place) = out_place {
                                         self.visit_place(
                                             out_place,
                                             PlaceContext::MutatingUse(MutatingUseContext::Store),
-                                            source_location,
+                                            location,
                                         );
                                     }
                                 }
                                 InlineAsmOperand::SymFn { value } => {
-                                    self.visit_constant(value, source_location);
+                                    self.visit_constant(value, location);
                                 }
                                 InlineAsmOperand::SymStatic { def_id: _ } => {}
                             }
diff --git a/src/librustc_middle/traits/query.rs b/src/librustc_middle/traits/query.rs
index e030125b5b15c..69696ac9e93c0 100644
--- a/src/librustc_middle/traits/query.rs
+++ b/src/librustc_middle/traits/query.rs
@@ -221,7 +221,7 @@ pub fn trivial_dropck_outlives<'tcx>(tcx: TyCtxt<'tcx>, ty: Ty<'tcx>) -> bool {
         | ty::Ref(..)
         | ty::Str
         | ty::Foreign(..)
-        | ty::Error => true,
+        | ty::Error(_) => true,
 
         // [T; N] and [T] have same properties as T.
         ty::Array(ty, _) | ty::Slice(ty) => trivial_dropck_outlives(tcx, ty),
diff --git a/src/librustc_middle/ty/_match.rs b/src/librustc_middle/ty/_match.rs
index 02abe868f3943..db9229ae3d214 100644
--- a/src/librustc_middle/ty/_match.rs
+++ b/src/librustc_middle/ty/_match.rs
@@ -79,7 +79,7 @@ impl TypeRelation<'tcx> for Match<'tcx> {
                 Err(TypeError::Sorts(relate::expected_found(self, &a, &b)))
             }
 
-            (&ty::Error, _) | (_, &ty::Error) => Ok(self.tcx().types.err),
+            (&ty::Error(_), _) | (_, &ty::Error(_)) => Ok(self.tcx().ty_error()),
 
             _ => relate::super_relate_tys(self, a, b),
         }
diff --git a/src/librustc_middle/ty/context.rs b/src/librustc_middle/ty/context.rs
index de2e1046f1cbb..62d6de2d71e6d 100644
--- a/src/librustc_middle/ty/context.rs
+++ b/src/librustc_middle/ty/context.rs
@@ -46,7 +46,7 @@ use rustc_session::lint::{Level, Lint};
 use rustc_session::Session;
 use rustc_span::source_map::MultiSpan;
 use rustc_span::symbol::{kw, sym, Symbol};
-use rustc_span::Span;
+use rustc_span::{Span, DUMMY_SP};
 use rustc_target::abi::{Layout, TargetDataLayout, VariantIdx};
 use rustc_target::spec::abi;
 
@@ -145,7 +145,6 @@ pub struct CommonTypes<'tcx> {
     pub f64: Ty<'tcx>,
     pub never: Ty<'tcx>,
     pub self_param: Ty<'tcx>,
-    pub err: Ty<'tcx>,
 
     /// Dummy type used for the `Self` of a `TraitRef` created for converting
     /// a trait object, and which gets removed in `ExistentialTraitRef`.
@@ -803,7 +802,6 @@ impl<'tcx> CommonTypes<'tcx> {
             bool: mk(Bool),
             char: mk(Char),
             never: mk(Never),
-            err: mk(Error),
             isize: mk(Int(ast::IntTy::Isize)),
             i8: mk(Int(ast::IntTy::I8)),
             i16: mk(Int(ast::IntTy::I16)),
@@ -1142,6 +1140,31 @@ impl<'tcx> TyCtxt<'tcx> {
         }
     }
 
+    /// Constructs a `TyKind::Error` type and registers a `delay_span_bug` to ensure it gets used.
+    #[track_caller]
+    pub fn ty_error(self) -> Ty<'tcx> {
+        self.ty_error_with_message(DUMMY_SP, "TyKind::Error constructed but no error reported")
+    }
+
+    /// Constructs a `TyKind::Error` type and registers a `delay_span_bug` with the given `msg to
+    /// ensure it gets used.
+    #[track_caller]
+    pub fn ty_error_with_message<S: Into<MultiSpan>>(self, span: S, msg: &str) -> Ty<'tcx> {
+        self.sess.delay_span_bug(span, msg);
+        self.mk_ty(Error(super::sty::DelaySpanBugEmitted(())))
+    }
+
+    /// Like `err` but for constants.
+    #[track_caller]
+    pub fn const_error(self, ty: Ty<'tcx>) -> &'tcx Const<'tcx> {
+        self.sess
+            .delay_span_bug(DUMMY_SP, "ty::ConstKind::Error constructed but no error reported.");
+        self.mk_const(ty::Const {
+            val: ty::ConstKind::Error(super::sty::DelaySpanBugEmitted(())),
+            ty,
+        })
+    }
+
     pub fn consider_optimizing<T: Fn() -> String>(&self, msg: T) -> bool {
         let cname = self.crate_name(LOCAL_CRATE).as_str();
         self.sess.consider_optimizing(&cname, msg)
@@ -1382,7 +1405,10 @@ impl<'tcx> TyCtxt<'tcx> {
         })
     }
 
-    pub fn return_type_impl_or_dyn_trait(&self, scope_def_id: DefId) -> Option<(Span, bool)> {
+    pub fn return_type_impl_or_dyn_trait(
+        &self,
+        scope_def_id: DefId,
+    ) -> Option<&'tcx hir::Ty<'tcx>> {
         let hir_id = self.hir().as_local_hir_id(scope_def_id.expect_local());
         let hir_output = match self.hir().get(hir_id) {
             Node::Item(hir::Item {
@@ -1428,15 +1454,17 @@ impl<'tcx> TyCtxt<'tcx> {
                 let output = self.erase_late_bound_regions(&sig.output());
                 if output.is_impl_trait() {
                     let fn_decl = self.hir().fn_decl_by_hir_id(hir_id).unwrap();
-                    Some((fn_decl.output.span(), false))
+                    if let hir::FnRetTy::Return(ty) = fn_decl.output {
+                        return Some(ty);
+                    }
                 } else {
                     let mut v = TraitObjectVisitor(vec![]);
                     rustc_hir::intravisit::walk_ty(&mut v, hir_output);
                     if v.0.len() == 1 {
-                        return Some((v.0[0], true));
+                        return Some(v.0[0]);
                     }
-                    None
                 }
+                None
             }
             _ => None,
         }
@@ -1845,7 +1873,7 @@ macro_rules! sty_debug_print {
                     let variant = match t.kind {
                         ty::Bool | ty::Char | ty::Int(..) | ty::Uint(..) |
                             ty::Float(..) | ty::Str | ty::Never => continue,
-                        ty::Error => /* unimportant */ continue,
+                        ty::Error(_) => /* unimportant */ continue,
                         $(ty::$variant(..) => &mut $variant,)*
                     };
                     let lt = t.flags.intersects(ty::TypeFlags::HAS_RE_INFER);
diff --git a/src/librustc_middle/ty/diagnostics.rs b/src/librustc_middle/ty/diagnostics.rs
index 2e9aa724ac5af..a2812e117ed39 100644
--- a/src/librustc_middle/ty/diagnostics.rs
+++ b/src/librustc_middle/ty/diagnostics.rs
@@ -236,21 +236,24 @@ pub fn suggest_constraining_type_param(
     }
 }
 
-pub struct TraitObjectVisitor(pub Vec<rustc_span::Span>);
-impl<'v> hir::intravisit::Visitor<'v> for TraitObjectVisitor {
+pub struct TraitObjectVisitor<'tcx>(pub Vec<&'tcx hir::Ty<'tcx>>);
+impl<'v> hir::intravisit::Visitor<'v> for TraitObjectVisitor<'v> {
     type Map = rustc_hir::intravisit::ErasedMap<'v>;
 
     fn nested_visit_map(&mut self) -> hir::intravisit::NestedVisitorMap<Self::Map> {
         hir::intravisit::NestedVisitorMap::None
     }
 
-    fn visit_ty(&mut self, ty: &hir::Ty<'_>) {
+    fn visit_ty(&mut self, ty: &'v hir::Ty<'v>) {
         if let hir::TyKind::TraitObject(
             _,
-            hir::Lifetime { name: hir::LifetimeName::ImplicitObjectLifetimeDefault, .. },
+            hir::Lifetime {
+                name: hir::LifetimeName::ImplicitObjectLifetimeDefault | hir::LifetimeName::Static,
+                ..
+            },
         ) = ty.kind
         {
-            self.0.push(ty.span);
+            self.0.push(ty);
         }
     }
 }
diff --git a/src/librustc_middle/ty/error.rs b/src/librustc_middle/ty/error.rs
index be3bf748225b9..6113359ca93a7 100644
--- a/src/librustc_middle/ty/error.rs
+++ b/src/librustc_middle/ty/error.rs
@@ -286,14 +286,14 @@ impl<'tcx> ty::TyS<'tcx> {
             ty::Projection(_) => "associated type".into(),
             ty::Param(p) => format!("type parameter `{}`", p).into(),
             ty::Opaque(..) => "opaque type".into(),
-            ty::Error => "type error".into(),
+            ty::Error(_) => "type error".into(),
         }
     }
 
     pub fn prefix_string(&self) -> Cow<'static, str> {
         match self.kind {
             ty::Infer(_)
-            | ty::Error
+            | ty::Error(_)
             | ty::Bool
             | ty::Char
             | ty::Int(_)
diff --git a/src/librustc_middle/ty/fast_reject.rs b/src/librustc_middle/ty/fast_reject.rs
index 16d8e37940763..b0fb179b18bdf 100644
--- a/src/librustc_middle/ty/fast_reject.rs
+++ b/src/librustc_middle/ty/fast_reject.rs
@@ -104,7 +104,7 @@ pub fn simplify_type(
         }
         ty::Opaque(def_id, _) => Some(OpaqueSimplifiedType(def_id)),
         ty::Foreign(def_id) => Some(ForeignSimplifiedType(def_id)),
-        ty::Placeholder(..) | ty::Bound(..) | ty::Infer(_) | ty::Error => None,
+        ty::Placeholder(..) | ty::Bound(..) | ty::Infer(_) | ty::Error(_) => None,
     }
 }
 
diff --git a/src/librustc_middle/ty/flags.rs b/src/librustc_middle/ty/flags.rs
index edcb69c5e8cbd..bee42be8a5388 100644
--- a/src/librustc_middle/ty/flags.rs
+++ b/src/librustc_middle/ty/flags.rs
@@ -70,7 +70,7 @@ impl FlagComputation {
             | &ty::Str
             | &ty::Foreign(..) => {}
 
-            &ty::Error => self.add_flags(TypeFlags::HAS_ERROR),
+            &ty::Error(_) => self.add_flags(TypeFlags::HAS_ERROR),
 
             &ty::Param(_) => {
                 self.add_flags(TypeFlags::HAS_TY_PARAM);
@@ -227,7 +227,7 @@ impl FlagComputation {
                 self.add_flags(TypeFlags::STILL_FURTHER_SPECIALIZABLE);
             }
             ty::ConstKind::Value(_) => {}
-            ty::ConstKind::Error => self.add_flags(TypeFlags::HAS_ERROR),
+            ty::ConstKind::Error(_) => self.add_flags(TypeFlags::HAS_ERROR),
         }
     }
 
diff --git a/src/librustc_middle/ty/layout.rs b/src/librustc_middle/ty/layout.rs
index f5bca90c2bd52..d58ebdc8dfc4d 100644
--- a/src/librustc_middle/ty/layout.rs
+++ b/src/librustc_middle/ty/layout.rs
@@ -1245,7 +1245,7 @@ impl<'tcx> LayoutCx<'tcx, TyCtxt<'tcx>> {
                 bug!("Layout::compute: unexpected type `{}`", ty)
             }
 
-            ty::Param(_) | ty::Error => {
+            ty::Param(_) | ty::Error(_) => {
                 return Err(LayoutError::Unknown(ty));
             }
         })
@@ -2141,7 +2141,7 @@ where
             | ty::Opaque(..)
             | ty::Param(_)
             | ty::Infer(_)
-            | ty::Error => bug!("TyAndLayout::field_type: unexpected type `{}`", this.ty),
+            | ty::Error(_) => bug!("TyAndLayout::field_type: unexpected type `{}`", this.ty),
         })
     }
 
diff --git a/src/librustc_middle/ty/outlives.rs b/src/librustc_middle/ty/outlives.rs
index 1da042e161737..1a8693b8df711 100644
--- a/src/librustc_middle/ty/outlives.rs
+++ b/src/librustc_middle/ty/outlives.rs
@@ -171,7 +171,7 @@ fn compute_components(tcx: TyCtxt<'tcx>, ty: Ty<'tcx>, out: &mut SmallVec<[Compo
             ty::Dynamic(..) |     // OutlivesObject, OutlivesFragment (*)
             ty::Placeholder(..) |
             ty::Bound(..) |
-            ty::Error => {
+            ty::Error(_) => {
                 // (*) Function pointers and trait objects are both binders.
                 // In the RFC, this means we would add the bound regions to
                 // the "bound regions list".  In our representation, no such
diff --git a/src/librustc_middle/ty/print/mod.rs b/src/librustc_middle/ty/print/mod.rs
index 69b36980bd73c..6c8f23c139f6e 100644
--- a/src/librustc_middle/ty/print/mod.rs
+++ b/src/librustc_middle/ty/print/mod.rs
@@ -298,7 +298,7 @@ pub fn characteristic_def_id_of_type(ty: Ty<'_>) -> Option<DefId> {
         | ty::Opaque(..)
         | ty::Infer(_)
         | ty::Bound(..)
-        | ty::Error
+        | ty::Error(_)
         | ty::GeneratorWitness(..)
         | ty::Never
         | ty::Float(_) => None,
diff --git a/src/librustc_middle/ty/print/obsolete.rs b/src/librustc_middle/ty/print/obsolete.rs
index 7d9943ab07902..67b6433b61143 100644
--- a/src/librustc_middle/ty/print/obsolete.rs
+++ b/src/librustc_middle/ty/print/obsolete.rs
@@ -144,7 +144,7 @@ impl DefPathBasedNames<'tcx> {
                 let substs = substs.truncate_to(self.tcx, generics);
                 self.push_generic_params(substs, iter::empty(), output, debug);
             }
-            ty::Error
+            ty::Error(_)
             | ty::Bound(..)
             | ty::Infer(_)
             | ty::Placeholder(..)
diff --git a/src/librustc_middle/ty/print/pretty.rs b/src/librustc_middle/ty/print/pretty.rs
index d782dd07a6588..17203fcce5e59 100644
--- a/src/librustc_middle/ty/print/pretty.rs
+++ b/src/librustc_middle/ty/print/pretty.rs
@@ -518,7 +518,7 @@ pub trait PrettyPrinter<'tcx>:
                     p!(write("{}", infer_ty))
                 }
             }
-            ty::Error => p!(write("[type error]")),
+            ty::Error(_) => p!(write("[type error]")),
             ty::Param(ref param_ty) => p!(write("{}", param_ty)),
             ty::Bound(debruijn, bound_ty) => match bound_ty.kind {
                 ty::BoundTyKind::Anon => self.pretty_print_bound_var(debruijn, bound_ty.var)?,
@@ -919,7 +919,7 @@ pub trait PrettyPrinter<'tcx>:
                 self.pretty_print_bound_var(debruijn, bound_var)?
             }
             ty::ConstKind::Placeholder(placeholder) => p!(write("Placeholder({:?})", placeholder)),
-            ty::ConstKind::Error => p!(write("[const error]")),
+            ty::ConstKind::Error(_) => p!(write("[const error]")),
         };
         Ok(self)
     }
diff --git a/src/librustc_middle/ty/query/values.rs b/src/librustc_middle/ty/query/values.rs
index b1f76ff6a03bd..0a0ff101b5203 100644
--- a/src/librustc_middle/ty/query/values.rs
+++ b/src/librustc_middle/ty/query/values.rs
@@ -17,7 +17,7 @@ impl<'tcx> Value<'tcx> for &'_ TyS<'_> {
     fn from_cycle_error(tcx: TyCtxt<'tcx>) -> Self {
         // SAFETY: This is never called when `Self` is not `Ty<'tcx>`.
         // FIXME: Represent the above fact in the trait system somehow.
-        unsafe { std::mem::transmute::<Ty<'tcx>, Ty<'_>>(tcx.types.err) }
+        unsafe { std::mem::transmute::<Ty<'tcx>, Ty<'_>>(tcx.ty_error()) }
     }
 }
 
@@ -33,7 +33,7 @@ impl<'tcx> Value<'tcx> for AdtSizedConstraint<'_> {
         // FIXME: Represent the above fact in the trait system somehow.
         unsafe {
             std::mem::transmute::<AdtSizedConstraint<'tcx>, AdtSizedConstraint<'_>>(
-                AdtSizedConstraint(tcx.intern_type_list(&[tcx.types.err])),
+                AdtSizedConstraint(tcx.intern_type_list(&[tcx.ty_error()])),
             )
         }
     }
diff --git a/src/librustc_middle/ty/relate.rs b/src/librustc_middle/ty/relate.rs
index cddd7081ca375..14cddd11c438d 100644
--- a/src/librustc_middle/ty/relate.rs
+++ b/src/librustc_middle/ty/relate.rs
@@ -354,7 +354,7 @@ pub fn super_relate_tys<R: TypeRelation<'tcx>>(
             bug!("bound types encountered in super_relate_tys")
         }
 
-        (&ty::Error, _) | (_, &ty::Error) => Ok(tcx.types.err),
+        (&ty::Error(_), _) | (_, &ty::Error(_)) => Ok(tcx.ty_error()),
 
         (&ty::Never, _)
         | (&ty::Char, _)
@@ -524,7 +524,7 @@ pub fn super_relate_consts<R: TypeRelation<'tcx>>(
             bug!("var types encountered in super_relate_consts: {:?} {:?}", a, b)
         }
 
-        (ty::ConstKind::Error, _) | (_, ty::ConstKind::Error) => Ok(ty::ConstKind::Error),
+        (ty::ConstKind::Error(d), _) | (_, ty::ConstKind::Error(d)) => Ok(ty::ConstKind::Error(d)),
 
         (ty::ConstKind::Param(a_p), ty::ConstKind::Param(b_p)) if a_p.index == b_p.index => {
             return Ok(a);
diff --git a/src/librustc_middle/ty/structural_impls.rs b/src/librustc_middle/ty/structural_impls.rs
index f6f5dfd651612..f04d31601ea5b 100644
--- a/src/librustc_middle/ty/structural_impls.rs
+++ b/src/librustc_middle/ty/structural_impls.rs
@@ -911,7 +911,7 @@ impl<'tcx> TypeFoldable<'tcx> for Ty<'tcx> {
             | ty::Int(_)
             | ty::Uint(_)
             | ty::Float(_)
-            | ty::Error
+            | ty::Error(_)
             | ty::Infer(_)
             | ty::Param(..)
             | ty::Bound(..)
@@ -952,7 +952,7 @@ impl<'tcx> TypeFoldable<'tcx> for Ty<'tcx> {
             | ty::Int(_)
             | ty::Uint(_)
             | ty::Float(_)
-            | ty::Error
+            | ty::Error(_)
             | ty::Infer(_)
             | ty::Bound(..)
             | ty::Placeholder(..)
@@ -1051,7 +1051,7 @@ impl<'tcx> TypeFoldable<'tcx> for ty::ConstKind<'tcx> {
             ty::ConstKind::Value(_)
             | ty::ConstKind::Bound(..)
             | ty::ConstKind::Placeholder(..)
-            | ty::ConstKind::Error => *self,
+            | ty::ConstKind::Error(_) => *self,
         }
     }
 
@@ -1063,7 +1063,7 @@ impl<'tcx> TypeFoldable<'tcx> for ty::ConstKind<'tcx> {
             ty::ConstKind::Value(_)
             | ty::ConstKind::Bound(..)
             | ty::ConstKind::Placeholder(_)
-            | ty::ConstKind::Error => false,
+            | ty::ConstKind::Error(_) => false,
         }
     }
 }
diff --git a/src/librustc_middle/ty/sty.rs b/src/librustc_middle/ty/sty.rs
index fad96aa86cc0a..cf11adb0285ac 100644
--- a/src/librustc_middle/ty/sty.rs
+++ b/src/librustc_middle/ty/sty.rs
@@ -203,9 +203,15 @@ pub enum TyKind<'tcx> {
 
     /// A placeholder for a type which could not be computed; this is
     /// propagated to avoid useless error messages.
-    Error,
+    Error(DelaySpanBugEmitted),
 }
 
+/// A type that is not publicly constructable. This prevents people from making `TyKind::Error`
+/// except through `tcx.err*()`.
+#[derive(Copy, Clone, Debug, Eq, Hash, PartialEq, PartialOrd, Ord)]
+#[derive(RustcEncodable, RustcDecodable, HashStable)]
+pub struct DelaySpanBugEmitted(pub(super) ());
+
 // `TyKind` is used a lot. Make sure it doesn't unintentionally get bigger.
 #[cfg(target_arch = "x86_64")]
 static_assert_size!(TyKind<'_>, 24);
@@ -1984,7 +1990,7 @@ impl<'tcx> TyS<'tcx> {
     #[inline]
     pub fn has_concrete_skeleton(&self) -> bool {
         match self.kind {
-            Param(_) | Infer(_) | Error => false,
+            Param(_) | Infer(_) | Error(_) => false,
             _ => true,
         }
     }
@@ -2016,7 +2022,7 @@ impl<'tcx> TyS<'tcx> {
         match self.kind {
             FnDef(def_id, substs) => tcx.fn_sig(def_id).subst(tcx, substs),
             FnPtr(f) => f,
-            Error => {
+            Error(_) => {
                 // ignore errors (#54954)
                 ty::Binder::dummy(FnSig::fake())
             }
@@ -2140,7 +2146,7 @@ impl<'tcx> TyS<'tcx> {
             // closure type is not yet known
             Bound(..) | Infer(_) => None,
 
-            Error => Some(ty::ClosureKind::Fn),
+            Error(_) => Some(ty::ClosureKind::Fn),
 
             _ => bug!("cannot convert type `{:?}` to a closure kind", self),
         }
@@ -2167,7 +2173,7 @@ impl<'tcx> TyS<'tcx> {
             | ty::Array(..)
             | ty::Closure(..)
             | ty::Never
-            | ty::Error => true,
+            | ty::Error(_) => true,
 
             ty::Str | ty::Slice(_) | ty::Dynamic(..) | ty::Foreign(..) => false,
 
@@ -2372,9 +2378,7 @@ impl<'tcx> Const<'tcx> {
                 // can leak through `val` into the const we return.
                 Ok(val) => Const::from_value(tcx, val, self.ty),
                 Err(ErrorHandled::TooGeneric | ErrorHandled::Linted) => self,
-                Err(ErrorHandled::Reported(ErrorReported)) => {
-                    tcx.mk_const(ty::Const { val: ty::ConstKind::Error, ty: self.ty })
-                }
+                Err(ErrorHandled::Reported(ErrorReported)) => tcx.const_error(self.ty),
             }
         } else {
             self
@@ -2434,7 +2438,7 @@ pub enum ConstKind<'tcx> {
 
     /// A placeholder for a const which could not be computed; this is
     /// propagated to avoid useless error messages.
-    Error,
+    Error(DelaySpanBugEmitted),
 }
 
 #[cfg(target_arch = "x86_64")]
diff --git a/src/librustc_middle/ty/util.rs b/src/librustc_middle/ty/util.rs
index ff284b709c2cf..47110be53b252 100644
--- a/src/librustc_middle/ty/util.rs
+++ b/src/librustc_middle/ty/util.rs
@@ -176,7 +176,7 @@ impl<'tcx> TyCtxt<'tcx> {
         if let ty::Adt(def, substs) = ty.kind {
             for field in def.all_fields() {
                 let field_ty = field.ty(self, substs);
-                if let Error = field_ty.kind {
+                if let Error(_) = field_ty.kind {
                     return true;
                 }
             }
@@ -731,7 +731,7 @@ impl<'tcx> ty::TyS<'tcx> {
             | ty::Ref(..)
             | ty::RawPtr(_)
             | ty::FnDef(..)
-            | ty::Error
+            | ty::Error(_)
             | ty::FnPtr(_) => true,
             ty::Tuple(_) => self.tuple_fields().all(Self::is_trivially_freeze),
             ty::Slice(elem_ty) | ty::Array(elem_ty, _) => elem_ty.is_trivially_freeze(),
@@ -826,7 +826,7 @@ impl<'tcx> ty::TyS<'tcx> {
             // called for known, fully-monomorphized types.
             Projection(_) | Opaque(..) | Param(_) | Bound(..) | Placeholder(_) | Infer(_) => false,
 
-            Foreign(_) | GeneratorWitness(..) | Error => false,
+            Foreign(_) | GeneratorWitness(..) | Error(_) => false,
         }
     }
 
@@ -1109,7 +1109,7 @@ pub fn needs_drop_components(
         // Foreign types can never have destructors.
         ty::Foreign(..) => Ok(SmallVec::new()),
 
-        ty::Dynamic(..) | ty::Error => Err(AlwaysRequiresDrop),
+        ty::Dynamic(..) | ty::Error(_) => Err(AlwaysRequiresDrop),
 
         ty::Slice(ty) => needs_drop_components(ty, target_layout),
         ty::Array(elem_ty, size) => {
diff --git a/src/librustc_middle/ty/walk.rs b/src/librustc_middle/ty/walk.rs
index bf988a4302633..d6f504fdb338b 100644
--- a/src/librustc_middle/ty/walk.rs
+++ b/src/librustc_middle/ty/walk.rs
@@ -108,7 +108,7 @@ fn push_inner<'tcx>(stack: &mut TypeWalkerStack<'tcx>, parent: GenericArg<'tcx>)
             | ty::Infer(_)
             | ty::Param(_)
             | ty::Never
-            | ty::Error
+            | ty::Error(_)
             | ty::Placeholder(..)
             | ty::Bound(..)
             | ty::Foreign(..) => {}
@@ -171,7 +171,7 @@ fn push_inner<'tcx>(stack: &mut TypeWalkerStack<'tcx>, parent: GenericArg<'tcx>)
                 | ty::ConstKind::Placeholder(_)
                 | ty::ConstKind::Bound(..)
                 | ty::ConstKind::Value(_)
-                | ty::ConstKind::Error => {}
+                | ty::ConstKind::Error(_) => {}
 
                 ty::ConstKind::Unevaluated(_, substs, _) => {
                     stack.extend(substs.iter().rev());
diff --git a/src/librustc_mir/borrow_check/invalidation.rs b/src/librustc_mir/borrow_check/invalidation.rs
index 17fa641ae6c17..fd8f17718e795 100644
--- a/src/librustc_mir/borrow_check/invalidation.rs
+++ b/src/librustc_mir/borrow_check/invalidation.rs
@@ -2,7 +2,7 @@ use rustc_data_structures::graph::dominators::Dominators;
 use rustc_middle::mir::visit::Visitor;
 use rustc_middle::mir::{BasicBlock, Body, Location, Place, Rvalue};
 use rustc_middle::mir::{BorrowKind, Mutability, Operand};
-use rustc_middle::mir::{InlineAsmOperand, TerminatorKind};
+use rustc_middle::mir::{InlineAsmOperand, Terminator, TerminatorKind};
 use rustc_middle::mir::{Statement, StatementKind};
 use rustc_middle::ty::TyCtxt;
 
@@ -112,14 +112,14 @@ impl<'cx, 'tcx> Visitor<'tcx> for InvalidationGenerator<'cx, 'tcx> {
         self.super_statement(statement, location);
     }
 
-    fn visit_terminator_kind(&mut self, kind: &TerminatorKind<'tcx>, location: Location) {
+    fn visit_terminator(&mut self, terminator: &Terminator<'tcx>, location: Location) {
         self.check_activations(location);
 
-        match kind {
+        match &terminator.kind {
             TerminatorKind::SwitchInt { ref discr, switch_ty: _, values: _, targets: _ } => {
                 self.consume_operand(location, discr);
             }
-            TerminatorKind::Drop { location: drop_place, target: _, unwind: _ } => {
+            TerminatorKind::Drop { place: drop_place, target: _, unwind: _ } => {
                 self.access_place(
                     location,
                     *drop_place,
@@ -128,7 +128,7 @@ impl<'cx, 'tcx> Visitor<'tcx> for InvalidationGenerator<'cx, 'tcx> {
                 );
             }
             TerminatorKind::DropAndReplace {
-                location: drop_place,
+                place: drop_place,
                 value: ref new_value,
                 target: _,
                 unwind: _,
@@ -222,7 +222,7 @@ impl<'cx, 'tcx> Visitor<'tcx> for InvalidationGenerator<'cx, 'tcx> {
             }
         }
 
-        self.super_terminator_kind(kind, location);
+        self.super_terminator(terminator, location);
     }
 }
 
diff --git a/src/librustc_mir/borrow_check/mod.rs b/src/librustc_mir/borrow_check/mod.rs
index d099f48adc5c6..83691d439eb81 100644
--- a/src/librustc_mir/borrow_check/mod.rs
+++ b/src/librustc_mir/borrow_check/mod.rs
@@ -663,7 +663,7 @@ impl<'cx, 'tcx> dataflow::ResultsVisitor<'cx, 'tcx> for MirBorrowckCtxt<'cx, 'tc
             TerminatorKind::SwitchInt { ref discr, switch_ty: _, values: _, targets: _ } => {
                 self.consume_operand(loc, (discr, span), flow_state);
             }
-            TerminatorKind::Drop { location: ref drop_place, target: _, unwind: _ } => {
+            TerminatorKind::Drop { place: ref drop_place, target: _, unwind: _ } => {
                 let tcx = self.infcx.tcx;
 
                 // Compute the type with accurate region information.
@@ -692,7 +692,7 @@ impl<'cx, 'tcx> dataflow::ResultsVisitor<'cx, 'tcx> for MirBorrowckCtxt<'cx, 'tc
                 );
             }
             TerminatorKind::DropAndReplace {
-                location: drop_place,
+                place: drop_place,
                 value: ref new_value,
                 target: _,
                 unwind: _,
diff --git a/src/librustc_mir/borrow_check/type_check/free_region_relations.rs b/src/librustc_mir/borrow_check/type_check/free_region_relations.rs
index 5707127340d87..beee31812563e 100644
--- a/src/librustc_mir/borrow_check/type_check/free_region_relations.rs
+++ b/src/librustc_mir/borrow_check/type_check/free_region_relations.rs
@@ -264,7 +264,7 @@ impl UniversalRegionRelationsBuilder<'cx, 'tcx> {
                             .tcx
                             .sess
                             .delay_span_bug(DUMMY_SP, &format!("failed to normalize {:?}", ty));
-                        (self.infcx.tcx.types.err, None)
+                        (self.infcx.tcx.ty_error(), None)
                     });
                 let constraints2 = self.add_implied_bounds(ty);
                 normalized_inputs_and_output.push(ty);
diff --git a/src/librustc_mir/borrow_check/type_check/mod.rs b/src/librustc_mir/borrow_check/type_check/mod.rs
index 7cf4fdfcf3c5b..0e35cafb9f3e9 100644
--- a/src/librustc_mir/borrow_check/type_check/mod.rs
+++ b/src/librustc_mir/borrow_check/type_check/mod.rs
@@ -498,7 +498,7 @@ impl<'a, 'b, 'tcx> TypeVerifier<'a, 'b, 'tcx> {
             if place_ty.variant_index.is_none() {
                 if place_ty.ty.references_error() {
                     assert!(self.errors_reported);
-                    return PlaceTy::from_ty(self.tcx().types.err);
+                    return PlaceTy::from_ty(self.tcx().ty_error());
                 }
             }
             place_ty = self.sanitize_projection(place_ty, elem, place, location)
@@ -725,7 +725,7 @@ impl<'a, 'b, 'tcx> TypeVerifier<'a, 'b, 'tcx> {
 
     fn error(&mut self) -> Ty<'tcx> {
         self.errors_reported = true;
-        self.tcx().types.err
+        self.tcx().ty_error()
     }
 
     fn field_ty(
@@ -1558,8 +1558,8 @@ impl<'a, 'tcx> TypeChecker<'a, 'tcx> {
                 // no checks needed for these
             }
 
-            TerminatorKind::DropAndReplace { ref location, ref value, target: _, unwind: _ } => {
-                let place_ty = location.ty(body, tcx).ty;
+            TerminatorKind::DropAndReplace { ref place, ref value, target: _, unwind: _ } => {
+                let place_ty = place.ty(body, tcx).ty;
                 let rv_ty = value.ty(body, tcx);
 
                 let locations = term_location.to_locations();
diff --git a/src/librustc_mir/borrow_check/used_muts.rs b/src/librustc_mir/borrow_check/used_muts.rs
index 2da72f3bcc517..e027056842db9 100644
--- a/src/librustc_mir/borrow_check/used_muts.rs
+++ b/src/librustc_mir/borrow_check/used_muts.rs
@@ -1,5 +1,7 @@
 use rustc_middle::mir::visit::{PlaceContext, Visitor};
-use rustc_middle::mir::{Local, Location, Place, Statement, StatementKind, TerminatorKind};
+use rustc_middle::mir::{
+    Local, Location, Place, Statement, StatementKind, Terminator, TerminatorKind,
+};
 
 use rustc_data_structures::fx::FxHashSet;
 
@@ -62,20 +64,22 @@ impl GatherUsedMutsVisitor<'_, '_, '_> {
 }
 
 impl<'visit, 'cx, 'tcx> Visitor<'tcx> for GatherUsedMutsVisitor<'visit, 'cx, 'tcx> {
-    fn visit_terminator_kind(&mut self, kind: &TerminatorKind<'tcx>, _location: Location) {
-        debug!("visit_terminator_kind: kind={:?}", kind);
-        match &kind {
+    fn visit_terminator(&mut self, terminator: &Terminator<'tcx>, location: Location) {
+        debug!("visit_terminator: terminator={:?}", terminator);
+        match &terminator.kind {
             TerminatorKind::Call { destination: Some((into, _)), .. } => {
                 self.remove_never_initialized_mut_locals(*into);
             }
-            TerminatorKind::DropAndReplace { location, .. } => {
-                self.remove_never_initialized_mut_locals(*location);
+            TerminatorKind::DropAndReplace { place, .. } => {
+                self.remove_never_initialized_mut_locals(*place);
             }
             _ => {}
         }
+
+        self.super_terminator(terminator, location);
     }
 
-    fn visit_statement(&mut self, statement: &Statement<'tcx>, _location: Location) {
+    fn visit_statement(&mut self, statement: &Statement<'tcx>, location: Location) {
         if let StatementKind::Assign(box (into, _)) = &statement.kind {
             debug!(
                 "visit_statement: statement={:?} local={:?} \
@@ -84,6 +88,8 @@ impl<'visit, 'cx, 'tcx> Visitor<'tcx> for GatherUsedMutsVisitor<'visit, 'cx, 'tc
             );
             self.remove_never_initialized_mut_locals(*into);
         }
+
+        self.super_statement(statement, location);
     }
 
     fn visit_local(&mut self, local: &Local, place_context: PlaceContext, location: Location) {
diff --git a/src/librustc_mir/dataflow/framework/direction.rs b/src/librustc_mir/dataflow/framework/direction.rs
index 6c9cb529dc2f3..4512ae96c0833 100644
--- a/src/librustc_mir/dataflow/framework/direction.rs
+++ b/src/librustc_mir/dataflow/framework/direction.rs
@@ -441,8 +441,8 @@ impl Direction for Forward {
             Goto { target } => propagate(target, exit_state),
 
             Assert { target, cleanup: unwind, expected: _, msg: _, cond: _ }
-            | Drop { target, unwind, location: _ }
-            | DropAndReplace { target, unwind, value: _, location: _ }
+            | Drop { target, unwind, place: _ }
+            | DropAndReplace { target, unwind, value: _, place: _ }
             | FalseUnwind { real_target: target, unwind } => {
                 if let Some(unwind) = unwind {
                     if dead_unwinds.map_or(true, |dead| !dead.contains(bb)) {
diff --git a/src/librustc_mir/dataflow/impls/borrowed_locals.rs b/src/librustc_mir/dataflow/impls/borrowed_locals.rs
index 1d49a32e19645..70c916a089270 100644
--- a/src/librustc_mir/dataflow/impls/borrowed_locals.rs
+++ b/src/librustc_mir/dataflow/impls/borrowed_locals.rs
@@ -189,8 +189,8 @@ where
         self.super_terminator(terminator, location);
 
         match terminator.kind {
-            mir::TerminatorKind::Drop { location: dropped_place, .. }
-            | mir::TerminatorKind::DropAndReplace { location: dropped_place, .. } => {
+            mir::TerminatorKind::Drop { place: dropped_place, .. }
+            | mir::TerminatorKind::DropAndReplace { place: dropped_place, .. } => {
                 // See documentation for `unsound_ignore_borrow_on_drop` for an explanation.
                 if !self.ignore_borrow_on_drop {
                     self.trans.gen(dropped_place.local);
diff --git a/src/librustc_mir/dataflow/move_paths/builder.rs b/src/librustc_mir/dataflow/move_paths/builder.rs
index 41c7bd95a96cc..7c8aa1db71ff8 100644
--- a/src/librustc_mir/dataflow/move_paths/builder.rs
+++ b/src/librustc_mir/dataflow/move_paths/builder.rs
@@ -387,13 +387,13 @@ impl<'b, 'a, 'tcx> Gatherer<'b, 'a, 'tcx> {
                 self.gather_init(place.as_ref(), InitKind::Deep);
             }
 
-            TerminatorKind::Drop { location, target: _, unwind: _ } => {
-                self.gather_move(location);
+            TerminatorKind::Drop { place, target: _, unwind: _ } => {
+                self.gather_move(place);
             }
-            TerminatorKind::DropAndReplace { location, ref value, .. } => {
-                self.create_move_path(location);
+            TerminatorKind::DropAndReplace { place, ref value, .. } => {
+                self.create_move_path(place);
                 self.gather_operand(value);
-                self.gather_init(location.as_ref(), InitKind::Deep);
+                self.gather_init(place.as_ref(), InitKind::Deep);
             }
             TerminatorKind::Call {
                 ref func,
diff --git a/src/librustc_mir/interpret/intrinsics/type_name.rs b/src/librustc_mir/interpret/intrinsics/type_name.rs
index 71cca725982f5..379117f3b846a 100644
--- a/src/librustc_mir/interpret/intrinsics/type_name.rs
+++ b/src/librustc_mir/interpret/intrinsics/type_name.rs
@@ -50,7 +50,7 @@ impl<'tcx> Printer<'tcx> for AbsolutePathPrinter<'tcx> {
             | ty::Dynamic(_, _) => self.pretty_print_type(ty),
 
             // Placeholders (all printed as `_` to uniformize them).
-            ty::Param(_) | ty::Bound(..) | ty::Placeholder(_) | ty::Infer(_) | ty::Error => {
+            ty::Param(_) | ty::Bound(..) | ty::Placeholder(_) | ty::Infer(_) | ty::Error(_) => {
                 write!(self, "_")?;
                 Ok(self)
             }
diff --git a/src/librustc_mir/interpret/operand.rs b/src/librustc_mir/interpret/operand.rs
index 38f5988d0eb3f..0cb878a49dcf1 100644
--- a/src/librustc_mir/interpret/operand.rs
+++ b/src/librustc_mir/interpret/operand.rs
@@ -527,7 +527,7 @@ impl<'mir, 'tcx: 'mir, M: Machine<'mir, 'tcx>> InterpCx<'mir, 'tcx, M> {
         // Early-return cases.
         let val_val = match val.val {
             ty::ConstKind::Param(_) => throw_inval!(TooGeneric),
-            ty::ConstKind::Error => throw_inval!(TypeckError(ErrorReported)),
+            ty::ConstKind::Error(_) => throw_inval!(TypeckError(ErrorReported)),
             ty::ConstKind::Unevaluated(def_id, substs, promoted) => {
                 let instance = self.resolve(def_id, substs)?;
                 // We use `const_eval` here and `const_eval_raw` elsewhere in mir interpretation.
diff --git a/src/librustc_mir/interpret/terminator.rs b/src/librustc_mir/interpret/terminator.rs
index cd7621ea9752b..1d57fce39734e 100644
--- a/src/librustc_mir/interpret/terminator.rs
+++ b/src/librustc_mir/interpret/terminator.rs
@@ -91,10 +91,10 @@ impl<'mir, 'tcx: 'mir, M: Machine<'mir, 'tcx>> InterpCx<'mir, 'tcx, M> {
                 }
             }
 
-            Drop { location, target, unwind } => {
-                let place = self.eval_place(location)?;
+            Drop { place, target, unwind } => {
+                let place = self.eval_place(place)?;
                 let ty = place.layout.ty;
-                trace!("TerminatorKind::drop: {:?}, type {}", location, ty);
+                trace!("TerminatorKind::drop: {:?}, type {}", place, ty);
 
                 let instance = Instance::resolve_drop_in_place(*self.tcx, ty);
                 self.drop_in_place(place, instance, target, unwind)?;
diff --git a/src/librustc_mir/interpret/validity.rs b/src/librustc_mir/interpret/validity.rs
index 7e3b6c08e08f4..999f2fe76b4da 100644
--- a/src/librustc_mir/interpret/validity.rs
+++ b/src/librustc_mir/interpret/validity.rs
@@ -561,7 +561,7 @@ impl<'rt, 'mir, 'tcx: 'mir, M: Machine<'mir, 'tcx>> ValidityVisitor<'rt, 'mir, '
             | ty::Generator(..) => Ok(false),
             // Some types only occur during typechecking, they have no layout.
             // We should not see them here and we could not check them anyway.
-            ty::Error
+            ty::Error(_)
             | ty::Infer(..)
             | ty::Placeholder(..)
             | ty::Bound(..)
diff --git a/src/librustc_mir/monomorphize/collector.rs b/src/librustc_mir/monomorphize/collector.rs
index fc17aa9c31c59..36f3947d83017 100644
--- a/src/librustc_mir/monomorphize/collector.rs
+++ b/src/librustc_mir/monomorphize/collector.rs
@@ -624,19 +624,19 @@ impl<'a, 'tcx> MirVisitor<'tcx> for MirNeighborCollector<'a, 'tcx> {
         self.super_const(constant);
     }
 
-    fn visit_terminator_kind(&mut self, kind: &mir::TerminatorKind<'tcx>, location: Location) {
-        debug!("visiting terminator {:?} @ {:?}", kind, location);
+    fn visit_terminator(&mut self, terminator: &mir::Terminator<'tcx>, location: Location) {
+        debug!("visiting terminator {:?} @ {:?}", terminator, location);
 
         let tcx = self.tcx;
-        match *kind {
+        match terminator.kind {
             mir::TerminatorKind::Call { ref func, .. } => {
                 let callee_ty = func.ty(self.body, tcx);
                 let callee_ty = self.monomorphize(callee_ty);
                 visit_fn_use(self.tcx, callee_ty, true, &mut self.output);
             }
-            mir::TerminatorKind::Drop { ref location, .. }
-            | mir::TerminatorKind::DropAndReplace { ref location, .. } => {
-                let ty = location.ty(self.body, self.tcx).ty;
+            mir::TerminatorKind::Drop { ref place, .. }
+            | mir::TerminatorKind::DropAndReplace { ref place, .. } => {
+                let ty = place.ty(self.body, self.tcx).ty;
                 let ty = self.monomorphize(ty);
                 visit_drop_use(self.tcx, ty, true, self.output);
             }
@@ -671,7 +671,7 @@ impl<'a, 'tcx> MirVisitor<'tcx> for MirNeighborCollector<'a, 'tcx> {
             | mir::TerminatorKind::FalseUnwind { .. } => bug!(),
         }
 
-        self.super_terminator_kind(kind, location);
+        self.super_terminator(terminator, location);
     }
 
     fn visit_local(
diff --git a/src/librustc_mir/shim.rs b/src/librustc_mir/shim.rs
index f95fd9b9e90c5..71fff85153141 100644
--- a/src/librustc_mir/shim.rs
+++ b/src/librustc_mir/shim.rs
@@ -582,7 +582,7 @@ impl CloneShimBuilder<'tcx> {
         self.block(
             vec![],
             TerminatorKind::Drop {
-                location: self.tcx.mk_place_index(dest, beg),
+                place: self.tcx.mk_place_index(dest, beg),
                 target: BasicBlock::new(8),
                 unwind: None,
             },
@@ -634,7 +634,7 @@ impl CloneShimBuilder<'tcx> {
                 self.block(
                     vec![],
                     TerminatorKind::Drop {
-                        location: previous_field,
+                        place: previous_field,
                         target: previous_cleanup,
                         unwind: None,
                     },
@@ -799,11 +799,7 @@ fn build_call_shim<'tcx>(
         block(
             &mut blocks,
             vec![],
-            TerminatorKind::Drop {
-                location: rcvr_place(),
-                target: BasicBlock::new(2),
-                unwind: None,
-            },
+            TerminatorKind::Drop { place: rcvr_place(), target: BasicBlock::new(2), unwind: None },
             false,
         );
     }
@@ -814,11 +810,7 @@ fn build_call_shim<'tcx>(
         block(
             &mut blocks,
             vec![],
-            TerminatorKind::Drop {
-                location: rcvr_place(),
-                target: BasicBlock::new(4),
-                unwind: None,
-            },
+            TerminatorKind::Drop { place: rcvr_place(), target: BasicBlock::new(4), unwind: None },
             true,
         );
 
diff --git a/src/librustc_mir/transform/add_moves_for_packed_drops.rs b/src/librustc_mir/transform/add_moves_for_packed_drops.rs
index 39ce2340aed21..a02d0f655600d 100644
--- a/src/librustc_mir/transform/add_moves_for_packed_drops.rs
+++ b/src/librustc_mir/transform/add_moves_for_packed_drops.rs
@@ -64,8 +64,8 @@ fn add_moves_for_packed_drops_patch<'tcx>(
         let terminator = data.terminator();
 
         match terminator.kind {
-            TerminatorKind::Drop { location, .. }
-                if util::is_disaligned(tcx, body, param_env, location) =>
+            TerminatorKind::Drop { place, .. }
+                if util::is_disaligned(tcx, body, param_env, place) =>
             {
                 add_move_for_packed_drop(tcx, body, &mut patch, terminator, loc, data.is_cleanup);
             }
@@ -88,13 +88,13 @@ fn add_move_for_packed_drop<'tcx>(
     is_cleanup: bool,
 ) {
     debug!("add_move_for_packed_drop({:?} @ {:?})", terminator, loc);
-    let (location, target, unwind) = match terminator.kind {
-        TerminatorKind::Drop { ref location, target, unwind } => (location, target, unwind),
+    let (place, target, unwind) = match terminator.kind {
+        TerminatorKind::Drop { ref place, target, unwind } => (place, target, unwind),
         _ => unreachable!(),
     };
 
     let source_info = terminator.source_info;
-    let ty = location.ty(body, tcx).ty;
+    let ty = place.ty(body, tcx).ty;
     let temp = patch.new_temp(ty, terminator.source_info.span);
 
     let storage_dead_block = patch.new_block(BasicBlockData {
@@ -104,9 +104,9 @@ fn add_move_for_packed_drop<'tcx>(
     });
 
     patch.add_statement(loc, StatementKind::StorageLive(temp));
-    patch.add_assign(loc, Place::from(temp), Rvalue::Use(Operand::Move(*location)));
+    patch.add_assign(loc, Place::from(temp), Rvalue::Use(Operand::Move(*place)));
     patch.patch_terminator(
         loc.block,
-        TerminatorKind::Drop { location: Place::from(temp), target: storage_dead_block, unwind },
+        TerminatorKind::Drop { place: Place::from(temp), target: storage_dead_block, unwind },
     );
 }
diff --git a/src/librustc_mir/transform/check_consts/post_drop_elaboration.rs b/src/librustc_mir/transform/check_consts/post_drop_elaboration.rs
index 226e0e2049ebd..124606fb423e6 100644
--- a/src/librustc_mir/transform/check_consts/post_drop_elaboration.rs
+++ b/src/librustc_mir/transform/check_consts/post_drop_elaboration.rs
@@ -78,7 +78,7 @@ impl Visitor<'tcx> for CheckLiveDrops<'mir, 'tcx> {
         trace!("visit_terminator: terminator={:?} location={:?}", terminator, location);
 
         match &terminator.kind {
-            mir::TerminatorKind::Drop { location: dropped_place, .. } => {
+            mir::TerminatorKind::Drop { place: dropped_place, .. } => {
                 let dropped_ty = dropped_place.ty(self.body, self.tcx).ty;
                 if !NeedsDrop::in_any_value_of_ty(self.ccx, dropped_ty) {
                     return;
diff --git a/src/librustc_mir/transform/check_consts/resolver.rs b/src/librustc_mir/transform/check_consts/resolver.rs
index a81d7a23be2fb..b8104292aab23 100644
--- a/src/librustc_mir/transform/check_consts/resolver.rs
+++ b/src/librustc_mir/transform/check_consts/resolver.rs
@@ -121,25 +121,25 @@ where
         self.super_assign(place, rvalue, location);
     }
 
-    fn visit_terminator_kind(&mut self, kind: &mir::TerminatorKind<'tcx>, location: Location) {
+    fn visit_terminator(&mut self, terminator: &mir::Terminator<'tcx>, location: Location) {
         // The effect of assignment to the return place in `TerminatorKind::Call` is not applied
         // here; that occurs in `apply_call_return_effect`.
 
-        if let mir::TerminatorKind::DropAndReplace { value, location: dest, .. } = kind {
+        if let mir::TerminatorKind::DropAndReplace { value, place, .. } = &terminator.kind {
             let qualif = qualifs::in_operand::<Q, _>(
                 self.ccx,
                 &mut |l| self.qualifs_per_local.contains(l),
                 value,
             );
 
-            if !dest.is_indirect() {
-                self.assign_qualif_direct(dest, qualif);
+            if !place.is_indirect() {
+                self.assign_qualif_direct(place, qualif);
             }
         }
 
         // We need to assign qualifs to the dropped location before visiting the operand that
         // replaces it since qualifs can be cleared on move.
-        self.super_terminator_kind(kind, location);
+        self.super_terminator(terminator, location);
     }
 }
 
diff --git a/src/librustc_mir/transform/check_consts/validation.rs b/src/librustc_mir/transform/check_consts/validation.rs
index 428a74bcdcbfb..35a8df62cb83a 100644
--- a/src/librustc_mir/transform/check_consts/validation.rs
+++ b/src/librustc_mir/transform/check_consts/validation.rs
@@ -560,8 +560,8 @@ impl Visitor<'tcx> for Validator<'mir, 'tcx> {
 
             // Forbid all `Drop` terminators unless the place being dropped is a local with no
             // projections that cannot be `NeedsDrop`.
-            TerminatorKind::Drop { location: dropped_place, .. }
-            | TerminatorKind::DropAndReplace { location: dropped_place, .. } => {
+            TerminatorKind::Drop { place: dropped_place, .. }
+            | TerminatorKind::DropAndReplace { place: dropped_place, .. } => {
                 // If we are checking live drops after drop-elaboration, don't emit duplicate
                 // errors here.
                 if super::post_drop_elaboration::checking_enabled(self.tcx) {
diff --git a/src/librustc_mir/transform/elaborate_drops.rs b/src/librustc_mir/transform/elaborate_drops.rs
index e4129f447d532..1704d8baabdc8 100644
--- a/src/librustc_mir/transform/elaborate_drops.rs
+++ b/src/librustc_mir/transform/elaborate_drops.rs
@@ -85,15 +85,15 @@ fn find_dead_unwinds<'tcx>(
         .iterate_to_fixpoint()
         .into_results_cursor(body);
     for (bb, bb_data) in body.basic_blocks().iter_enumerated() {
-        let location = match bb_data.terminator().kind {
-            TerminatorKind::Drop { ref location, unwind: Some(_), .. }
-            | TerminatorKind::DropAndReplace { ref location, unwind: Some(_), .. } => location,
+        let place = match bb_data.terminator().kind {
+            TerminatorKind::Drop { ref place, unwind: Some(_), .. }
+            | TerminatorKind::DropAndReplace { ref place, unwind: Some(_), .. } => place,
             _ => continue,
         };
 
         debug!("find_dead_unwinds @ {:?}: {:?}", bb, bb_data);
 
-        let path = match env.move_data.rev_lookup.find(location.as_ref()) {
+        let path = match env.move_data.rev_lookup.find(place.as_ref()) {
             LookupResult::Exact(e) => e,
             LookupResult::Parent(..) => {
                 debug!("find_dead_unwinds: has parent; skipping");
@@ -105,7 +105,7 @@ fn find_dead_unwinds<'tcx>(
         debug!(
             "find_dead_unwinds @ {:?}: path({:?})={:?}; init_data={:?}",
             bb,
-            location,
+            place,
             path,
             flow_inits.get()
         );
@@ -294,16 +294,16 @@ impl<'b, 'tcx> ElaborateDropsCtxt<'b, 'tcx> {
     fn collect_drop_flags(&mut self) {
         for (bb, data) in self.body.basic_blocks().iter_enumerated() {
             let terminator = data.terminator();
-            let location = match terminator.kind {
-                TerminatorKind::Drop { ref location, .. }
-                | TerminatorKind::DropAndReplace { ref location, .. } => location,
+            let place = match terminator.kind {
+                TerminatorKind::Drop { ref place, .. }
+                | TerminatorKind::DropAndReplace { ref place, .. } => place,
                 _ => continue,
             };
 
             self.init_data.seek_before(self.body.terminator_loc(bb));
 
-            let path = self.move_data().rev_lookup.find(location.as_ref());
-            debug!("collect_drop_flags: {:?}, place {:?} ({:?})", bb, location, path);
+            let path = self.move_data().rev_lookup.find(place.as_ref());
+            debug!("collect_drop_flags: {:?}, place {:?} ({:?})", bb, place, path);
 
             let path = match path {
                 LookupResult::Exact(e) => e,
@@ -315,7 +315,7 @@ impl<'b, 'tcx> ElaborateDropsCtxt<'b, 'tcx> {
                             terminator.source_info.span,
                             "drop of untracked, uninitialized value {:?}, place {:?} ({:?})",
                             bb,
-                            location,
+                            place,
                             path
                         );
                     }
@@ -328,7 +328,7 @@ impl<'b, 'tcx> ElaborateDropsCtxt<'b, 'tcx> {
                 debug!(
                     "collect_drop_flags: collecting {:?} from {:?}@{:?} - {:?}",
                     child,
-                    location,
+                    place,
                     path,
                     (maybe_live, maybe_dead)
                 );
@@ -346,13 +346,13 @@ impl<'b, 'tcx> ElaborateDropsCtxt<'b, 'tcx> {
 
             let resume_block = self.patch.resume_block();
             match terminator.kind {
-                TerminatorKind::Drop { location, target, unwind } => {
+                TerminatorKind::Drop { place, target, unwind } => {
                     self.init_data.seek_before(loc);
-                    match self.move_data().rev_lookup.find(location.as_ref()) {
+                    match self.move_data().rev_lookup.find(place.as_ref()) {
                         LookupResult::Exact(path) => elaborate_drop(
                             &mut Elaborator { ctxt: self },
                             terminator.source_info,
-                            location,
+                            place,
                             path,
                             target,
                             if data.is_cleanup {
@@ -371,10 +371,10 @@ impl<'b, 'tcx> ElaborateDropsCtxt<'b, 'tcx> {
                         }
                     }
                 }
-                TerminatorKind::DropAndReplace { location, ref value, target, unwind } => {
+                TerminatorKind::DropAndReplace { place, ref value, target, unwind } => {
                     assert!(!data.is_cleanup);
 
-                    self.elaborate_replace(loc, location, value, target, unwind);
+                    self.elaborate_replace(loc, place, value, target, unwind);
                 }
                 _ => continue,
             }
@@ -396,7 +396,7 @@ impl<'b, 'tcx> ElaborateDropsCtxt<'b, 'tcx> {
     fn elaborate_replace(
         &mut self,
         loc: Location,
-        location: Place<'tcx>,
+        place: Place<'tcx>,
         value: &Operand<'tcx>,
         target: BasicBlock,
         unwind: Option<BasicBlock>,
@@ -407,7 +407,7 @@ impl<'b, 'tcx> ElaborateDropsCtxt<'b, 'tcx> {
         assert!(!data.is_cleanup, "DropAndReplace in unwind path not supported");
 
         let assign = Statement {
-            kind: StatementKind::Assign(box (location, Rvalue::Use(value.clone()))),
+            kind: StatementKind::Assign(box (place, Rvalue::Use(value.clone()))),
             source_info: terminator.source_info,
         };
 
@@ -427,14 +427,14 @@ impl<'b, 'tcx> ElaborateDropsCtxt<'b, 'tcx> {
             is_cleanup: false,
         });
 
-        match self.move_data().rev_lookup.find(location.as_ref()) {
+        match self.move_data().rev_lookup.find(place.as_ref()) {
             LookupResult::Exact(path) => {
                 debug!("elaborate_drop_and_replace({:?}) - tracked {:?}", terminator, path);
                 self.init_data.seek_before(loc);
                 elaborate_drop(
                     &mut Elaborator { ctxt: self },
                     terminator.source_info,
-                    location,
+                    place,
                     path,
                     target,
                     Unwind::To(unwind),
@@ -459,7 +459,7 @@ impl<'b, 'tcx> ElaborateDropsCtxt<'b, 'tcx> {
                 debug!("elaborate_drop_and_replace({:?}) - untracked {:?}", terminator, parent);
                 self.patch.patch_terminator(
                     bb,
-                    TerminatorKind::Drop { location, target, unwind: Some(unwind) },
+                    TerminatorKind::Drop { place, target, unwind: Some(unwind) },
                 );
             }
         }
diff --git a/src/librustc_mir/transform/generator.rs b/src/librustc_mir/transform/generator.rs
index acadb5385c9cf..c8702eeae1d5b 100644
--- a/src/librustc_mir/transform/generator.rs
+++ b/src/librustc_mir/transform/generator.rs
@@ -93,13 +93,13 @@ impl<'tcx> MutVisitor<'tcx> for RenameLocalVisitor<'tcx> {
         }
     }
 
-    fn visit_terminator_kind(&mut self, kind: &mut TerminatorKind<'tcx>, location: Location) {
-        match kind {
+    fn visit_terminator(&mut self, terminator: &mut Terminator<'tcx>, location: Location) {
+        match terminator.kind {
             TerminatorKind::Return => {
                 // Do not replace the implicit `_0` access here, as that's not possible. The
                 // transform already handles `return` correctly.
             }
-            _ => self.super_terminator_kind(kind, location),
+            _ => self.super_terminator(terminator, location),
         }
     }
 }
@@ -835,8 +835,8 @@ fn elaborate_generator_drops<'tcx>(tcx: TyCtxt<'tcx>, def_id: DefId, body: &mut
 
     for (block, block_data) in body.basic_blocks().iter_enumerated() {
         let (target, unwind, source_info) = match block_data.terminator() {
-            Terminator { source_info, kind: TerminatorKind::Drop { location, target, unwind } } => {
-                if let Some(local) = location.as_local() {
+            Terminator { source_info, kind: TerminatorKind::Drop { place, target, unwind } } => {
+                if let Some(local) = place.as_local() {
                     if local == SELF_ARG {
                         (target, unwind, source_info)
                     } else {
@@ -1102,11 +1102,8 @@ fn create_generator_resume_function<'tcx>(
 fn insert_clean_drop(body: &mut Body<'_>) -> BasicBlock {
     let return_block = insert_term_block(body, TerminatorKind::Return);
 
-    let term = TerminatorKind::Drop {
-        location: Place::from(SELF_ARG),
-        target: return_block,
-        unwind: None,
-    };
+    let term =
+        TerminatorKind::Drop { place: Place::from(SELF_ARG), target: return_block, unwind: None };
     let source_info = SourceInfo::outermost(body.span);
 
     // Create a block to destroy an unresumed generators. This can only destroy upvars.
diff --git a/src/librustc_mir/transform/inline.rs b/src/librustc_mir/transform/inline.rs
index 47aa4fbf60c03..db909494aed6b 100644
--- a/src/librustc_mir/transform/inline.rs
+++ b/src/librustc_mir/transform/inline.rs
@@ -319,13 +319,13 @@ impl Inliner<'tcx> {
             let term = blk.terminator();
             let mut is_drop = false;
             match term.kind {
-                TerminatorKind::Drop { ref location, target, unwind }
-                | TerminatorKind::DropAndReplace { ref location, target, unwind, .. } => {
+                TerminatorKind::Drop { ref place, target, unwind }
+                | TerminatorKind::DropAndReplace { ref place, target, unwind, .. } => {
                     is_drop = true;
                     work_list.push(target);
-                    // If the location doesn't actually need dropping, treat it like
+                    // If the place doesn't actually need dropping, treat it like
                     // a regular goto.
-                    let ty = location.ty(callee_body, tcx).subst(tcx, callsite.substs).ty;
+                    let ty = place.ty(callee_body, tcx).subst(tcx, callsite.substs).ty;
                     if ty.needs_drop(tcx, param_env) {
                         cost += CALL_PENALTY;
                         if let Some(unwind) = unwind {
@@ -731,14 +731,14 @@ impl<'a, 'tcx> MutVisitor<'tcx> for Integrator<'a, 'tcx> {
         }
     }
 
-    fn visit_terminator_kind(&mut self, kind: &mut TerminatorKind<'tcx>, loc: Location) {
+    fn visit_terminator(&mut self, terminator: &mut Terminator<'tcx>, loc: Location) {
         // Don't try to modify the implicit `_0` access on return (`return` terminators are
         // replaced down below anyways).
-        if !matches!(kind, TerminatorKind::Return) {
-            self.super_terminator_kind(kind, loc);
+        if !matches!(terminator.kind, TerminatorKind::Return) {
+            self.super_terminator(terminator, loc);
         }
 
-        match *kind {
+        match terminator.kind {
             TerminatorKind::GeneratorDrop | TerminatorKind::Yield { .. } => bug!(),
             TerminatorKind::Goto { ref mut target } => {
                 *target = self.update_target(*target);
@@ -782,11 +782,11 @@ impl<'a, 'tcx> MutVisitor<'tcx> for Integrator<'a, 'tcx> {
                 }
             }
             TerminatorKind::Return => {
-                *kind = TerminatorKind::Goto { target: self.return_block };
+                terminator.kind = TerminatorKind::Goto { target: self.return_block };
             }
             TerminatorKind::Resume => {
                 if let Some(tgt) = self.cleanup_block {
-                    *kind = TerminatorKind::Goto { target: tgt }
+                    terminator.kind = TerminatorKind::Goto { target: tgt }
                 }
             }
             TerminatorKind::Abort => {}
diff --git a/src/librustc_mir/transform/no_landing_pads.rs b/src/librustc_mir/transform/no_landing_pads.rs
index 3bffafa1b2f9c..1d83733e4cd30 100644
--- a/src/librustc_mir/transform/no_landing_pads.rs
+++ b/src/librustc_mir/transform/no_landing_pads.rs
@@ -34,10 +34,10 @@ impl<'tcx> MutVisitor<'tcx> for NoLandingPads<'tcx> {
         self.tcx
     }
 
-    fn visit_terminator_kind(&mut self, kind: &mut TerminatorKind<'tcx>, location: Location) {
-        if let Some(unwind) = kind.unwind_mut() {
+    fn visit_terminator(&mut self, terminator: &mut Terminator<'tcx>, location: Location) {
+        if let Some(unwind) = terminator.kind.unwind_mut() {
             unwind.take();
         }
-        self.super_terminator_kind(kind, location);
+        self.super_terminator(terminator, location);
     }
 }
diff --git a/src/librustc_mir/transform/promote_consts.rs b/src/librustc_mir/transform/promote_consts.rs
index e1311ccd3746f..330f6c1640ff4 100644
--- a/src/librustc_mir/transform/promote_consts.rs
+++ b/src/librustc_mir/transform/promote_consts.rs
@@ -147,7 +147,6 @@ struct Collector<'a, 'tcx> {
     ccx: &'a ConstCx<'a, 'tcx>,
     temps: IndexVec<Local, TempState>,
     candidates: Vec<Candidate>,
-    span: Span,
 }
 
 impl<'tcx> Visitor<'tcx> for Collector<'_, 'tcx> {
@@ -216,10 +215,10 @@ impl<'tcx> Visitor<'tcx> for Collector<'_, 'tcx> {
         }
     }
 
-    fn visit_terminator_kind(&mut self, kind: &TerminatorKind<'tcx>, location: Location) {
-        self.super_terminator_kind(kind, location);
+    fn visit_terminator(&mut self, terminator: &Terminator<'tcx>, location: Location) {
+        self.super_terminator(terminator, location);
 
-        match *kind {
+        match terminator.kind {
             TerminatorKind::Call { ref func, .. } => {
                 if let ty::FnDef(def_id, _) = func.ty(self.ccx.body, self.ccx.tcx).kind {
                     let fn_sig = self.ccx.tcx.fn_sig(def_id);
@@ -254,10 +253,6 @@ impl<'tcx> Visitor<'tcx> for Collector<'_, 'tcx> {
             _ => {}
         }
     }
-
-    fn visit_source_info(&mut self, source_info: &SourceInfo) {
-        self.span = source_info.span;
-    }
 }
 
 pub fn collect_temps_and_candidates(
@@ -267,7 +262,6 @@ pub fn collect_temps_and_candidates(
     let mut collector = Collector {
         temps: IndexVec::from_elem(TempState::Undefined, &ccx.body.local_decls),
         candidates: vec![],
-        span: ccx.body.span,
         ccx,
     };
     for (bb, data) in rpo {
@@ -1192,7 +1186,7 @@ pub fn promote_candidates<'tcx>(
             _ => true,
         });
         let terminator = block.terminator_mut();
-        if let TerminatorKind::Drop { location: place, target, .. } = &terminator.kind {
+        if let TerminatorKind::Drop { place, target, .. } = &terminator.kind {
             if let Some(index) = place.as_local() {
                 if promoted(index) {
                     terminator.kind = TerminatorKind::Goto { target: *target };
diff --git a/src/librustc_mir/transform/qualify_min_const_fn.rs b/src/librustc_mir/transform/qualify_min_const_fn.rs
index 4c8fc49099b2a..caf6c7715a9e1 100644
--- a/src/librustc_mir/transform/qualify_min_const_fn.rs
+++ b/src/librustc_mir/transform/qualify_min_const_fn.rs
@@ -349,9 +349,9 @@ fn check_terminator(
         | TerminatorKind::Resume
         | TerminatorKind::Unreachable => Ok(()),
 
-        TerminatorKind::Drop { location, .. } => check_place(tcx, *location, span, def_id, body),
-        TerminatorKind::DropAndReplace { location, value, .. } => {
-            check_place(tcx, *location, span, def_id, body)?;
+        TerminatorKind::Drop { place, .. } => check_place(tcx, *place, span, def_id, body),
+        TerminatorKind::DropAndReplace { place, value, .. } => {
+            check_place(tcx, *place, span, def_id, body)?;
             check_operand(tcx, value, span, def_id, body)
         }
 
diff --git a/src/librustc_mir/util/elaborate_drops.rs b/src/librustc_mir/util/elaborate_drops.rs
index a1345452ca979..5f55a812a4e0d 100644
--- a/src/librustc_mir/util/elaborate_drops.rs
+++ b/src/librustc_mir/util/elaborate_drops.rs
@@ -238,7 +238,7 @@ where
                 self.elaborator.patch().patch_terminator(
                     bb,
                     TerminatorKind::Drop {
-                        location: self.place,
+                        place: self.place,
                         target: self.succ,
                         unwind: self.unwind.into_option(),
                     },
@@ -723,7 +723,7 @@ where
         self.elaborator.patch().patch_terminator(
             drop_block,
             TerminatorKind::Drop {
-                location: tcx.mk_place_deref(ptr),
+                place: tcx.mk_place_deref(ptr),
                 target: loop_block,
                 unwind: unwind.into_option(),
             },
@@ -1000,7 +1000,7 @@ where
 
     fn drop_block(&mut self, target: BasicBlock, unwind: Unwind) -> BasicBlock {
         let block =
-            TerminatorKind::Drop { location: self.place, target, unwind: unwind.into_option() };
+            TerminatorKind::Drop { place: self.place, target, unwind: unwind.into_option() };
         self.new_block(unwind, block)
     }
 
diff --git a/src/librustc_mir_build/build/mod.rs b/src/librustc_mir_build/build/mod.rs
index 2efe93d057b9b..e2cf1bce733d6 100644
--- a/src/librustc_mir_build/build/mod.rs
+++ b/src/librustc_mir_build/build/mod.rs
@@ -687,7 +687,7 @@ fn construct_error<'a, 'tcx>(hir: Cx<'a, 'tcx>, body_id: hir::BodyId) -> Body<'t
     let tcx = hir.tcx();
     let owner_id = tcx.hir().body_owner(body_id);
     let span = tcx.hir().span(owner_id);
-    let ty = tcx.types.err;
+    let ty = tcx.ty_error();
     let num_params = match hir.body_owner_kind {
         hir::BodyOwnerKind::Fn => tcx.hir().fn_decl_by_hir_id(owner_id).unwrap().inputs.len(),
         hir::BodyOwnerKind::Closure => {
@@ -909,7 +909,9 @@ impl<'a, 'tcx> Builder<'a, 'tcx> {
                         self.local_decls[local].mutability = mutability;
                         self.local_decls[local].source_info.scope = self.source_scope;
                         self.local_decls[local].local_info = if let Some(kind) = self_binding {
-                            Some(box LocalInfo::User(ClearCrossCrate::Set(BindingForm::ImplicitSelf(*kind))))
+                            Some(box LocalInfo::User(ClearCrossCrate::Set(
+                                BindingForm::ImplicitSelf(*kind),
+                            )))
                         } else {
                             let binding_mode = ty::BindingMode::BindByValue(mutability);
                             Some(box LocalInfo::User(ClearCrossCrate::Set(BindingForm::Var(
diff --git a/src/librustc_mir_build/build/scope.rs b/src/librustc_mir_build/build/scope.rs
index 4daf567d7d451..b8df27094471f 100644
--- a/src/librustc_mir_build/build/scope.rs
+++ b/src/librustc_mir_build/build/scope.rs
@@ -1037,7 +1037,7 @@ impl<'a, 'tcx> Builder<'a, 'tcx> {
         &mut self,
         block: BasicBlock,
         span: Span,
-        location: Place<'tcx>,
+        place: Place<'tcx>,
         value: Operand<'tcx>,
     ) -> BlockAnd<()> {
         let source_info = self.source_info(span);
@@ -1047,7 +1047,7 @@ impl<'a, 'tcx> Builder<'a, 'tcx> {
             block,
             source_info,
             TerminatorKind::DropAndReplace {
-                location,
+                place,
                 value,
                 target: next_target,
                 unwind: Some(diverge_target),
@@ -1158,7 +1158,7 @@ fn build_scope_drops<'tcx>(
                     block,
                     source_info,
                     TerminatorKind::Drop {
-                        location: local.into(),
+                        place: local.into(),
                         target: next,
                         unwind: Some(unwind_to),
                     },
@@ -1272,7 +1272,7 @@ fn build_diverge_scope<'tcx>(
                         block,
                         source_info(drop_data.span),
                         TerminatorKind::Drop {
-                            location: drop_data.local.into(),
+                            place: drop_data.local.into(),
                             target,
                             unwind: None,
                         },
diff --git a/src/librustc_mir_build/hair/cx/expr.rs b/src/librustc_mir_build/hair/cx/expr.rs
index 703f6ef8dc41e..a1796c9433eac 100644
--- a/src/librustc_mir_build/hair/cx/expr.rs
+++ b/src/librustc_mir_build/hair/cx/expr.rs
@@ -478,7 +478,7 @@ fn make_mirror_unadjusted<'a, 'tcx>(
                                     );
 
                                     // Not a real fn, but we're not reaching codegen anyways...
-                                    ty = cx.tcx.types.err;
+                                    ty = cx.tcx.ty_error();
                                     InlineAsmOperand::SymFn {
                                         expr: Expr {
                                             ty,
diff --git a/src/librustc_mir_build/hair/pattern/mod.rs b/src/librustc_mir_build/hair/pattern/mod.rs
index e9aa7f597beb6..5c30b2a448c6d 100644
--- a/src/librustc_mir_build/hair/pattern/mod.rs
+++ b/src/librustc_mir_build/hair/pattern/mod.rs
@@ -509,7 +509,7 @@ impl<'a, 'tcx> PatCtxt<'a, 'tcx> {
     fn lower_pattern_unadjusted(&mut self, pat: &'tcx hir::Pat<'tcx>) -> Pat<'tcx> {
         let mut ty = self.tables.node_type(pat.hir_id);
 
-        if let ty::Error = ty.kind {
+        if let ty::Error(_) = ty.kind {
             // Avoid ICEs (e.g., #50577 and #50585).
             return Pat { span: pat.span, ty, kind: Box::new(PatKind::Wild) };
         }
@@ -708,7 +708,7 @@ impl<'a, 'tcx> PatCtxt<'a, 'tcx> {
                 if adt_def.is_enum() {
                     let substs = match ty.kind {
                         ty::Adt(_, substs) | ty::FnDef(_, substs) => substs,
-                        ty::Error => {
+                        ty::Error(_) => {
                             // Avoid ICE (#50585)
                             return PatKind::Wild;
                         }
@@ -1051,7 +1051,7 @@ crate fn compare_const_vals<'tcx>(
     let b_bits = b.try_eval_bits(tcx, param_env, ty);
 
     if let (Some(a), Some(b)) = (a_bits, b_bits) {
-        use ::rustc_apfloat::Float;
+        use rustc_apfloat::Float;
         return match ty.kind {
             ty::Float(ast::FloatTy::F32) => {
                 let l = ::rustc_apfloat::ieee::Single::from_bits(a);
diff --git a/src/librustc_parse/parser/diagnostics.rs b/src/librustc_parse/parser/diagnostics.rs
index 8792605c08d38..fc9ffc3092447 100644
--- a/src/librustc_parse/parser/diagnostics.rs
+++ b/src/librustc_parse/parser/diagnostics.rs
@@ -961,7 +961,7 @@ impl<'a> Parser<'a> {
             self.bump();
             let sp = self.prev_token.span;
             self.struct_span_err(sp, &msg)
-                .span_suggestion(sp, "change this to `;`", ";".to_string(), appl)
+                .span_suggestion_short(sp, "change this to `;`", ";".to_string(), appl)
                 .emit();
             return Ok(());
         } else if self.look_ahead(0, |t| {
diff --git a/src/librustc_parse/parser/stmt.rs b/src/librustc_parse/parser/stmt.rs
index 849193151c335..53f32b7c800bd 100644
--- a/src/librustc_parse/parser/stmt.rs
+++ b/src/librustc_parse/parser/stmt.rs
@@ -216,8 +216,28 @@ impl<'a> Parser<'a> {
     }
 
     /// Parses the RHS of a local variable declaration (e.g., '= 14;').
-    fn parse_initializer(&mut self, skip_eq: bool) -> PResult<'a, Option<P<Expr>>> {
-        if self.eat(&token::Eq) || skip_eq { Ok(Some(self.parse_expr()?)) } else { Ok(None) }
+    fn parse_initializer(&mut self, eq_optional: bool) -> PResult<'a, Option<P<Expr>>> {
+        let eq_consumed = match self.token.kind {
+            token::BinOpEq(..) => {
+                // Recover `let x <op>= 1` as `let x = 1`
+                self.struct_span_err(
+                    self.token.span,
+                    "can't reassign to an uninitialized variable",
+                )
+                .span_suggestion_short(
+                    self.token.span,
+                    "initialize the variable",
+                    "=".to_string(),
+                    Applicability::MaybeIncorrect,
+                )
+                .emit();
+                self.bump();
+                true
+            }
+            _ => self.eat(&token::Eq),
+        };
+
+        Ok(if eq_consumed || eq_optional { Some(self.parse_expr()?) } else { None })
     }
 
     /// Parses a block. No inner attributes are allowed.
diff --git a/src/librustc_passes/intrinsicck.rs b/src/librustc_passes/intrinsicck.rs
index e2bfcf18edb17..88fb78f85e423 100644
--- a/src/librustc_passes/intrinsicck.rs
+++ b/src/librustc_passes/intrinsicck.rs
@@ -150,7 +150,7 @@ impl ExprVisitor<'tcx> {
             _ => unreachable!(),
         };
         let asm_ty = match ty.kind {
-            ty::Never | ty::Error => return None,
+            ty::Never | ty::Error(_) => return None,
             ty::Int(IntTy::I8) | ty::Uint(UintTy::U8) => Some(InlineAsmType::I8),
             ty::Int(IntTy::I16) | ty::Uint(UintTy::U16) => Some(InlineAsmType::I16),
             ty::Int(IntTy::I32) | ty::Uint(UintTy::U32) => Some(InlineAsmType::I32),
@@ -167,7 +167,7 @@ impl ExprVisitor<'tcx> {
                 let fields = &adt.non_enum_variant().fields;
                 let elem_ty = fields[0].ty(self.tcx, substs);
                 match elem_ty.kind {
-                    ty::Never | ty::Error => return None,
+                    ty::Never | ty::Error(_) => return None,
                     ty::Int(IntTy::I8) | ty::Uint(UintTy::U8) => {
                         Some(InlineAsmType::VecI8(fields.len() as u64))
                     }
diff --git a/src/librustc_privacy/lib.rs b/src/librustc_privacy/lib.rs
index 3c1b56a9ef40a..9e6e7ea962bc3 100644
--- a/src/librustc_privacy/lib.rs
+++ b/src/librustc_privacy/lib.rs
@@ -220,7 +220,7 @@ where
             | ty::Ref(..)
             | ty::FnPtr(..)
             | ty::Param(..)
-            | ty::Error
+            | ty::Error(_)
             | ty::GeneratorWitness(..) => {}
             ty::Bound(..) | ty::Placeholder(..) | ty::Infer(..) => {
                 bug!("unexpected type: {:?}", ty)
diff --git a/src/librustc_resolve/build_reduced_graph.rs b/src/librustc_resolve/build_reduced_graph.rs
index e633bd1843e85..8432e34a5271c 100644
--- a/src/librustc_resolve/build_reduced_graph.rs
+++ b/src/librustc_resolve/build_reduced_graph.rs
@@ -485,6 +485,7 @@ impl<'a, 'b> BuildReducedGraphVisitor<'a, 'b> {
                             module_path.push(Segment {
                                 ident: Ident { name: kw::PathRoot, span: source.ident.span },
                                 id: Some(self.r.next_node_id()),
+                                has_generic_args: false,
                             });
                             source.ident.name = crate_name;
                         }
diff --git a/src/librustc_resolve/late/diagnostics.rs b/src/librustc_resolve/late/diagnostics.rs
index ed7adefcb8c9e..05ef0aa0bb689 100644
--- a/src/librustc_resolve/late/diagnostics.rs
+++ b/src/librustc_resolve/late/diagnostics.rs
@@ -920,20 +920,47 @@ impl<'a> LateResolutionVisitor<'a, '_, '_> {
         &self,
         path: &[Segment],
     ) -> Option<(Span, &'static str, String, Applicability)> {
-        let ident = match path {
-            [segment] => segment.ident,
+        let (ident, span) = match path {
+            [segment] if !segment.has_generic_args => {
+                (segment.ident.to_string(), segment.ident.span)
+            }
             _ => return None,
         };
-        match (
-            self.diagnostic_metadata.current_item,
-            self.diagnostic_metadata.currently_processing_generics,
-        ) {
-            (Some(Item { kind: ItemKind::Fn(..), ident, .. }), true) if ident.name == sym::main => {
+        let mut iter = ident.chars().map(|c| c.is_uppercase());
+        let single_uppercase_char =
+            matches!(iter.next(), Some(true)) && matches!(iter.next(), None);
+        if !self.diagnostic_metadata.currently_processing_generics && !single_uppercase_char {
+            return None;
+        }
+        match (self.diagnostic_metadata.current_item, single_uppercase_char) {
+            (Some(Item { kind: ItemKind::Fn(..), ident, .. }), _) if ident.name == sym::main => {
                 // Ignore `fn main()` as we don't want to suggest `fn main<T>()`
             }
-            (Some(Item { kind, .. }), true) => {
+            (
+                Some(Item {
+                    kind:
+                        kind @ ItemKind::Fn(..)
+                        | kind @ ItemKind::Enum(..)
+                        | kind @ ItemKind::Struct(..)
+                        | kind @ ItemKind::Union(..),
+                    ..
+                }),
+                true,
+            )
+            | (Some(Item { kind, .. }), false) => {
                 // Likely missing type parameter.
                 if let Some(generics) = kind.generics() {
+                    if span.overlaps(generics.span) {
+                        // Avoid the following:
+                        // error[E0405]: cannot find trait `A` in this scope
+                        //  --> $DIR/typo-suggestion-named-underscore.rs:CC:LL
+                        //   |
+                        // L | fn foo<T: A>(x: T) {} // Shouldn't suggest underscore
+                        //   |           ^- help: you might be missing a type parameter: `, A`
+                        //   |           |
+                        //   |           not found in this scope
+                        return None;
+                    }
                     let msg = "you might be missing a type parameter";
                     let (span, sugg) = if let [.., param] = &generics.params[..] {
                         let span = if let [.., bound] = &param.bounds[..] {
diff --git a/src/librustc_resolve/lib.rs b/src/librustc_resolve/lib.rs
index 61792e039c76e..cca9eabe7bcf8 100644
--- a/src/librustc_resolve/lib.rs
+++ b/src/librustc_resolve/lib.rs
@@ -225,13 +225,15 @@ enum VisResolutionError<'a> {
     ModuleOnly(Span),
 }
 
-// A minimal representation of a path segment. We use this in resolve because
-// we synthesize 'path segments' which don't have the rest of an AST or HIR
-// `PathSegment`.
+/// A minimal representation of a path segment. We use this in resolve because we synthesize 'path
+/// segments' which don't have the rest of an AST or HIR `PathSegment`.
 #[derive(Clone, Copy, Debug)]
 pub struct Segment {
     ident: Ident,
     id: Option<NodeId>,
+    /// Signals whether this `PathSegment` has generic arguments. Used to avoid providing
+    /// nonsensical suggestions.
+    has_generic_args: bool,
 }
 
 impl Segment {
@@ -240,7 +242,7 @@ impl Segment {
     }
 
     fn from_ident(ident: Ident) -> Segment {
-        Segment { ident, id: None }
+        Segment { ident, id: None, has_generic_args: false }
     }
 
     fn names_to_string(segments: &[Segment]) -> String {
@@ -250,7 +252,7 @@ impl Segment {
 
 impl<'a> From<&'a ast::PathSegment> for Segment {
     fn from(seg: &'a ast::PathSegment) -> Segment {
-        Segment { ident: seg.ident, id: Some(seg.id) }
+        Segment { ident: seg.ident, id: Some(seg.id), has_generic_args: seg.args.is_some() }
     }
 }
 
@@ -2017,7 +2019,7 @@ impl<'a> Resolver<'a> {
             path, opt_ns, record_used, path_span, crate_lint,
         );
 
-        for (i, &Segment { ident, id }) in path.iter().enumerate() {
+        for (i, &Segment { ident, id, has_generic_args: _ }) in path.iter().enumerate() {
             debug!("resolve_path ident {} {:?} {:?}", i, ident, id);
             let record_segment_res = |this: &mut Self, res| {
                 if record_used {
diff --git a/src/librustc_save_analysis/lib.rs b/src/librustc_save_analysis/lib.rs
index 12d2c8c7eb9a4..cae501e942b65 100644
--- a/src/librustc_save_analysis/lib.rs
+++ b/src/librustc_save_analysis/lib.rs
@@ -520,7 +520,7 @@ impl<'l, 'tcx> SaveContext<'l, 'tcx> {
     pub fn get_expr_data(&self, expr: &hir::Expr<'_>) -> Option<Data> {
         let hir_node = self.tcx.hir().expect_expr(expr.hir_id);
         let ty = self.tables.expr_ty_adjusted_opt(&hir_node);
-        if ty.is_none() || ty.unwrap().kind == ty::Error {
+        if ty.is_none() || matches!(ty.unwrap().kind, ty::Error(_)) {
             return None;
         }
         match expr.kind {
diff --git a/src/librustc_span/symbol.rs b/src/librustc_span/symbol.rs
index fdeb58b7b7a31..6f334bf37f5f1 100644
--- a/src/librustc_span/symbol.rs
+++ b/src/librustc_span/symbol.rs
@@ -345,6 +345,7 @@ symbols! {
         from_method,
         from_ok,
         from_usize,
+        from_trait,
         fundamental,
         future,
         Future,
diff --git a/src/librustc_symbol_mangling/v0.rs b/src/librustc_symbol_mangling/v0.rs
index 1a536b6a4294f..7d117b77cf5e5 100644
--- a/src/librustc_symbol_mangling/v0.rs
+++ b/src/librustc_symbol_mangling/v0.rs
@@ -345,7 +345,7 @@ impl Printer<'tcx> for SymbolMangler<'tcx> {
             ty::Never => "z",
 
             // Placeholders (should be demangled as `_`).
-            ty::Param(_) | ty::Bound(..) | ty::Placeholder(_) | ty::Infer(_) | ty::Error => "p",
+            ty::Param(_) | ty::Bound(..) | ty::Placeholder(_) | ty::Infer(_) | ty::Error(_) => "p",
 
             _ => "",
         };
@@ -367,7 +367,7 @@ impl Printer<'tcx> for SymbolMangler<'tcx> {
             ty::Tuple(_) if ty.is_unit() => unreachable!(),
 
             // Placeholders, also handled as part of basic types.
-            ty::Param(_) | ty::Bound(..) | ty::Placeholder(_) | ty::Infer(_) | ty::Error => {
+            ty::Param(_) | ty::Bound(..) | ty::Placeholder(_) | ty::Infer(_) | ty::Error(_) => {
                 unreachable!()
             }
 
diff --git a/src/librustc_trait_selection/opaque_types.rs b/src/librustc_trait_selection/opaque_types.rs
index d53a0ec9ef884..adccdd0b2617a 100644
--- a/src/librustc_trait_selection/opaque_types.rs
+++ b/src/librustc_trait_selection/opaque_types.rs
@@ -941,7 +941,7 @@ impl TypeFolder<'tcx> for ReverseMapper<'tcx> {
                             )
                             .emit();
 
-                        self.tcx().types.err
+                        self.tcx().ty_error()
                     }
                 }
             }
@@ -974,7 +974,7 @@ impl TypeFolder<'tcx> for ReverseMapper<'tcx> {
                             )
                             .emit();
 
-                        self.tcx().mk_const(ty::Const { val: ty::ConstKind::Error, ty: ct.ty })
+                        self.tcx().const_error(ct.ty)
                     }
                 }
             }
@@ -1002,7 +1002,7 @@ impl<'a, 'tcx> Instantiator<'a, 'tcx> {
             tcx,
             ty_op: |ty| {
                 if ty.references_error() {
-                    return tcx.types.err;
+                    return tcx.ty_error();
                 } else if let ty::Opaque(def_id, substs) = ty.kind {
                     // Check that this is `impl Trait` type is
                     // declared by `parent_def_id` -- i.e., one whose
diff --git a/src/librustc_trait_selection/traits/coherence.rs b/src/librustc_trait_selection/traits/coherence.rs
index 85c2f9246afcc..706cbf058b713 100644
--- a/src/librustc_trait_selection/traits/coherence.rs
+++ b/src/librustc_trait_selection/traits/coherence.rs
@@ -565,7 +565,7 @@ fn ty_is_non_local_constructor(ty: Ty<'_>, in_crate: InCrate) -> Option<Ty<'_>>
             }
         }
 
-        ty::Error => None,
+        ty::Error(_) => None,
 
         ty::Closure(..) | ty::Generator(..) | ty::GeneratorWitness(..) => {
             bug!("ty_is_local invoked on unexpected type: {:?}", ty)
diff --git a/src/librustc_trait_selection/traits/error_reporting/mod.rs b/src/librustc_trait_selection/traits/error_reporting/mod.rs
index d31e04cffd55f..e5a6c9a2e391a 100644
--- a/src/librustc_trait_selection/traits/error_reporting/mod.rs
+++ b/src/librustc_trait_selection/traits/error_reporting/mod.rs
@@ -1246,7 +1246,7 @@ impl<'a, 'tcx> InferCtxtPrivExt<'tcx> for InferCtxt<'a, 'tcx> {
                 ty::Generator(..) => Some(18),
                 ty::Foreign(..) => Some(19),
                 ty::GeneratorWitness(..) => Some(20),
-                ty::Placeholder(..) | ty::Bound(..) | ty::Infer(..) | ty::Error => None,
+                ty::Placeholder(..) | ty::Bound(..) | ty::Infer(..) | ty::Error(_) => None,
             }
         }
 
diff --git a/src/librustc_trait_selection/traits/error_reporting/suggestions.rs b/src/librustc_trait_selection/traits/error_reporting/suggestions.rs
index 8796cfb52165d..dfd7dac72d8e1 100644
--- a/src/librustc_trait_selection/traits/error_reporting/suggestions.rs
+++ b/src/librustc_trait_selection/traits/error_reporting/suggestions.rs
@@ -948,7 +948,7 @@ impl<'a, 'tcx> InferCtxtExt<'tcx> for InferCtxt<'a, 'tcx> {
              ty| {
                 let ty = self.resolve_vars_if_possible(&ty);
                 same &=
-                    ty.kind != ty::Error
+                    !matches!(ty.kind, ty::Error(_))
                         && last_ty.map_or(true, |last_ty| {
                             // FIXME: ideally we would use `can_coerce` here instead, but `typeck` comes
                             // *after* in the dependency graph.
@@ -1992,8 +1992,8 @@ impl<'a, 'tcx> InferCtxtExt<'tcx> for InferCtxt<'a, 'tcx> {
 /// Collect all the returned expressions within the input expression.
 /// Used to point at the return spans when we want to suggest some change to them.
 #[derive(Default)]
-struct ReturnsVisitor<'v> {
-    returns: Vec<&'v hir::Expr<'v>>,
+pub struct ReturnsVisitor<'v> {
+    pub returns: Vec<&'v hir::Expr<'v>>,
     in_block_tail: bool,
 }
 
diff --git a/src/librustc_trait_selection/traits/project.rs b/src/librustc_trait_selection/traits/project.rs
index 9492c3c340995..ed108613bfa23 100644
--- a/src/librustc_trait_selection/traits/project.rs
+++ b/src/librustc_trait_selection/traits/project.rs
@@ -784,7 +784,7 @@ struct Progress<'tcx> {
 
 impl<'tcx> Progress<'tcx> {
     fn error(tcx: TyCtxt<'tcx>) -> Self {
-        Progress { ty: tcx.types.err, obligations: vec![] }
+        Progress { ty: tcx.ty_error(), obligations: vec![] }
     }
 
     fn with_addl_obligations(mut self, mut obligations: Vec<PredicateObligation<'tcx>>) -> Self {
@@ -1085,7 +1085,7 @@ fn assemble_candidates_from_impls<'cx, 'tcx>(
                     | ty::Bound(..)
                     | ty::Placeholder(..)
                     | ty::Infer(..)
-                    | ty::Error => false,
+                    | ty::Error(_) => false,
                 }
             }
             super::ImplSourceParam(..) => {
@@ -1440,8 +1440,8 @@ fn confirm_param_env_candidate<'cx, 'tcx>(
                 obligation, poly_cache_entry, e,
             );
             debug!("confirm_param_env_candidate: {}", msg);
-            infcx.tcx.sess.delay_span_bug(obligation.cause.span, &msg);
-            Progress { ty: infcx.tcx.types.err, obligations: vec![] }
+            let err = infcx.tcx.ty_error_with_message(obligation.cause.span, &msg);
+            Progress { ty: err, obligations: vec![] }
         }
     }
 }
@@ -1460,7 +1460,7 @@ fn confirm_impl_candidate<'cx, 'tcx>(
     let param_env = obligation.param_env;
     let assoc_ty = match assoc_ty_def(selcx, impl_def_id, assoc_item_id) {
         Ok(assoc_ty) => assoc_ty,
-        Err(ErrorReported) => return Progress { ty: tcx.types.err, obligations: nested },
+        Err(ErrorReported) => return Progress { ty: tcx.ty_error(), obligations: nested },
     };
 
     if !assoc_ty.item.defaultness.has_value() {
@@ -1472,16 +1472,18 @@ fn confirm_impl_candidate<'cx, 'tcx>(
             "confirm_impl_candidate: no associated type {:?} for {:?}",
             assoc_ty.item.ident, obligation.predicate
         );
-        return Progress { ty: tcx.types.err, obligations: nested };
+        return Progress { ty: tcx.ty_error(), obligations: nested };
     }
     let substs = obligation.predicate.substs.rebase_onto(tcx, trait_def_id, substs);
     let substs =
         translate_substs(selcx.infcx(), param_env, impl_def_id, substs, assoc_ty.defining_node);
     let ty = tcx.type_of(assoc_ty.item.def_id);
     if substs.len() != tcx.generics_of(assoc_ty.item.def_id).count() {
-        tcx.sess
-            .delay_span_bug(DUMMY_SP, "impl item and trait item have different parameter counts");
-        Progress { ty: tcx.types.err, obligations: nested }
+        let err = tcx.ty_error_with_message(
+            DUMMY_SP,
+            "impl item and trait item have different parameter counts",
+        );
+        Progress { ty: err, obligations: nested }
     } else {
         Progress { ty: ty.subst(tcx, substs), obligations: nested }
     }
diff --git a/src/librustc_trait_selection/traits/query/dropck_outlives.rs b/src/librustc_trait_selection/traits/query/dropck_outlives.rs
index 856a2111fc82c..d07c95270e004 100644
--- a/src/librustc_trait_selection/traits/query/dropck_outlives.rs
+++ b/src/librustc_trait_selection/traits/query/dropck_outlives.rs
@@ -101,7 +101,7 @@ pub fn trivial_dropck_outlives<'tcx>(tcx: TyCtxt<'tcx>, ty: Ty<'tcx>) -> bool {
         | ty::Ref(..)
         | ty::Str
         | ty::Foreign(..)
-        | ty::Error => true,
+        | ty::Error(_) => true,
 
         // [T; N] and [T] have same properties as T.
         ty::Array(ty, _) | ty::Slice(ty) => trivial_dropck_outlives(tcx, ty),
diff --git a/src/librustc_trait_selection/traits/select/mod.rs b/src/librustc_trait_selection/traits/select/mod.rs
index 7ebf30f61c095..3fd566eab437e 100644
--- a/src/librustc_trait_selection/traits/select/mod.rs
+++ b/src/librustc_trait_selection/traits/select/mod.rs
@@ -1569,7 +1569,7 @@ impl<'cx, 'tcx> SelectionContext<'cx, 'tcx> {
             | ty::Array(..)
             | ty::Closure(..)
             | ty::Never
-            | ty::Error => {
+            | ty::Error(_) => {
                 // safe for everything
                 Where(ty::Binder::dummy(Vec::new()))
             }
@@ -1613,7 +1613,7 @@ impl<'cx, 'tcx> SelectionContext<'cx, 'tcx> {
             | ty::Infer(ty::FloatVar(_))
             | ty::FnDef(..)
             | ty::FnPtr(_)
-            | ty::Error => Where(ty::Binder::dummy(Vec::new())),
+            | ty::Error(_) => Where(ty::Binder::dummy(Vec::new())),
 
             ty::Uint(_)
             | ty::Int(_)
@@ -1690,7 +1690,7 @@ impl<'cx, 'tcx> SelectionContext<'cx, 'tcx> {
             | ty::FnDef(..)
             | ty::FnPtr(_)
             | ty::Str
-            | ty::Error
+            | ty::Error(_)
             | ty::Infer(ty::IntVar(_) | ty::FloatVar(_))
             | ty::Never
             | ty::Char => Vec::new(),
diff --git a/src/librustc_trait_selection/traits/structural_match.rs b/src/librustc_trait_selection/traits/structural_match.rs
index c4deb639140ca..201edf27a655c 100644
--- a/src/librustc_trait_selection/traits/structural_match.rs
+++ b/src/librustc_trait_selection/traits/structural_match.rs
@@ -219,7 +219,7 @@ impl<'a, 'tcx> TypeVisitor<'tcx> for Search<'a, 'tcx> {
             ty::Infer(_) | ty::Placeholder(_) | ty::Bound(..) => {
                 bug!("unexpected type during structural-match checking: {:?}", ty);
             }
-            ty::Error => {
+            ty::Error(_) => {
                 self.tcx().sess.delay_span_bug(self.span, "ty::Error in structural-match check");
                 // We still want to check other types after encountering an error,
                 // as this may still emit relevant errors.
diff --git a/src/librustc_trait_selection/traits/wf.rs b/src/librustc_trait_selection/traits/wf.rs
index 90a9b876d8ddf..1825c159ff3fb 100644
--- a/src/librustc_trait_selection/traits/wf.rs
+++ b/src/librustc_trait_selection/traits/wf.rs
@@ -392,7 +392,7 @@ impl<'a, 'tcx> WfPredicates<'a, 'tcx> {
                                 ));
                             }
                         }
-                        ty::ConstKind::Error
+                        ty::ConstKind::Error(_)
                         | ty::ConstKind::Param(_)
                         | ty::ConstKind::Bound(..)
                         | ty::ConstKind::Placeholder(..) => {
@@ -412,7 +412,7 @@ impl<'a, 'tcx> WfPredicates<'a, 'tcx> {
                 | ty::Int(..)
                 | ty::Uint(..)
                 | ty::Float(..)
-                | ty::Error
+                | ty::Error(_)
                 | ty::Str
                 | ty::GeneratorWitness(..)
                 | ty::Never
diff --git a/src/librustc_traits/chalk/lowering.rs b/src/librustc_traits/chalk/lowering.rs
index 9530b07e47cdb..c9dd06e9f1ba2 100644
--- a/src/librustc_traits/chalk/lowering.rs
+++ b/src/librustc_traits/chalk/lowering.rs
@@ -168,7 +168,7 @@ impl<'tcx> LowerInto<'tcx, chalk_ir::GoalData<RustInterner<'tcx>>> for ty::Predi
             ty::PredicateKind::WellFormed(arg) => match arg.unpack() {
                 GenericArgKind::Type(ty) => match ty.kind {
                     // These types are always WF.
-                    ty::Str | ty::Placeholder(..) | ty::Error | ty::Never => {
+                    ty::Str | ty::Placeholder(..) | ty::Error(_) | ty::Never => {
                         chalk_ir::GoalData::All(chalk_ir::Goals::new(interner))
                     }
 
@@ -376,7 +376,7 @@ impl<'tcx> LowerInto<'tcx, chalk_ir::Ty<RustInterner<'tcx>>> for Ty<'tcx> {
             })
             .intern(interner),
             Infer(_infer) => unimplemented!(),
-            Error => unimplemented!(),
+            Error(_) => unimplemented!(),
         }
     }
 }
diff --git a/src/librustc_traits/dropck_outlives.rs b/src/librustc_traits/dropck_outlives.rs
index 11c48559bd683..6339f8288d54e 100644
--- a/src/librustc_traits/dropck_outlives.rs
+++ b/src/librustc_traits/dropck_outlives.rs
@@ -271,7 +271,7 @@ fn dtorck_constraint_for_ty<'tcx>(
             constraints.dtorck_types.push(ty);
         }
 
-        ty::Placeholder(..) | ty::Bound(..) | ty::Infer(..) | ty::Error => {
+        ty::Placeholder(..) | ty::Bound(..) | ty::Infer(..) | ty::Error(_) => {
             // By the time this code runs, all type variables ought to
             // be fully resolved.
             return Err(NoSolution);
diff --git a/src/librustc_ty/ty.rs b/src/librustc_ty/ty.rs
index 99094246a6378..cf70a845af0aa 100644
--- a/src/librustc_ty/ty.rs
+++ b/src/librustc_ty/ty.rs
@@ -20,7 +20,7 @@ fn sized_constraint_for_ty<'tcx>(
         Bool | Char | Int(..) | Uint(..) | Float(..) | RawPtr(..) | Ref(..) | FnDef(..)
         | FnPtr(_) | Array(..) | Closure(..) | Generator(..) | Never => vec![],
 
-        Str | Dynamic(..) | Slice(_) | Foreign(..) | Error | GeneratorWitness(..) => {
+        Str | Dynamic(..) | Slice(_) | Foreign(..) | Error(_) | GeneratorWitness(..) => {
             // these are never sized - return the target type
             vec![ty]
         }
diff --git a/src/librustc_typeck/astconv.rs b/src/librustc_typeck/astconv.rs
index 267f3d9f3ef6e..7cdcb2face823 100644
--- a/src/librustc_typeck/astconv.rs
+++ b/src/librustc_typeck/astconv.rs
@@ -819,7 +819,7 @@ impl<'o, 'tcx> dyn AstConv<'tcx> + 'o {
                 (GenericParamDefKind::Type { .. }, GenericArg::Type(ty)) => {
                     if let (hir::TyKind::Infer, false) = (&ty.kind, self.allow_ty_infer()) {
                         inferred_params.push(ty.span);
-                        tcx.types.err.into()
+                        tcx.ty_error().into()
                     } else {
                         self.ast_ty_to_ty(&ty).into()
                     }
@@ -845,7 +845,7 @@ impl<'o, 'tcx> dyn AstConv<'tcx> + 'o {
                             // careful!
                             if default_needs_object_self(param) {
                                 missing_type_params.push(param.name.to_string());
-                                tcx.types.err.into()
+                                tcx.ty_error().into()
                             } else {
                                 // This is a default type parameter.
                                 self.normalize_ty(
@@ -865,7 +865,7 @@ impl<'o, 'tcx> dyn AstConv<'tcx> + 'o {
                             self.ty_infer(param, span).into()
                         } else {
                             // We've already errored above about the mismatch.
-                            tcx.types.err.into()
+                            tcx.ty_error().into()
                         }
                     }
                     GenericParamDefKind::Const => {
@@ -876,7 +876,7 @@ impl<'o, 'tcx> dyn AstConv<'tcx> + 'o {
                             self.ct_infer(ty, Some(param), span).into()
                         } else {
                             // We've already errored above about the mismatch.
-                            tcx.mk_const(ty::Const { val: ty::ConstKind::Error, ty }).into()
+                            tcx.const_error(ty).into()
                         }
                     }
                 }
@@ -1607,7 +1607,7 @@ impl<'o, 'tcx> dyn AstConv<'tcx> + 'o {
                 "at least one trait is required for an object type"
             )
             .emit();
-            return tcx.types.err;
+            return tcx.ty_error();
         }
 
         // Check that there are no gross object safety violations;
@@ -1624,7 +1624,7 @@ impl<'o, 'tcx> dyn AstConv<'tcx> + 'o {
                     &object_safety_violations[..],
                 )
                 .emit();
-                return tcx.types.err;
+                return tcx.ty_error();
             }
         }
 
@@ -2434,7 +2434,7 @@ impl<'o, 'tcx> dyn AstConv<'tcx> + 'o {
                 &path_str,
                 item_segment.ident.name,
             );
-            return tcx.types.err;
+            return tcx.ty_error();
         };
 
         debug!("qpath_to_ty: self_type={:?}", self_ty);
@@ -2792,7 +2792,7 @@ impl<'o, 'tcx> dyn AstConv<'tcx> + 'o {
             }
             Res::Err => {
                 self.set_tainted_by_errors();
-                self.tcx().types.err
+                self.tcx().ty_error()
             }
             _ => span_bug!(span, "unexpected resolution: {:?}", path.res),
         }
@@ -2860,7 +2860,7 @@ impl<'o, 'tcx> dyn AstConv<'tcx> + 'o {
                 };
                 self.associated_path_to_ty(ast_ty.hir_id, ast_ty.span, ty, res, segment, false)
                     .map(|(ty, _, _)| ty)
-                    .unwrap_or(tcx.types.err)
+                    .unwrap_or_else(|_| tcx.ty_error())
             }
             hir::TyKind::Array(ref ty, ref length) => {
                 let length_def_id = tcx.hir().local_def_id(length.hir_id);
@@ -2878,7 +2878,7 @@ impl<'o, 'tcx> dyn AstConv<'tcx> + 'o {
                 .span_label(ast_ty.span, "reserved keyword")
                 .emit();
 
-                tcx.types.err
+                tcx.ty_error()
             }
             hir::TyKind::Infer => {
                 // Infer also appears as the type of arguments or return
@@ -2887,7 +2887,7 @@ impl<'o, 'tcx> dyn AstConv<'tcx> + 'o {
                 // handled specially and will not descend into this routine.
                 self.ty_infer(None, ast_ty.span)
             }
-            hir::TyKind::Err => tcx.types.err,
+            hir::TyKind::Err => tcx.ty_error(),
         };
 
         debug!("ast_ty_to_ty: result_ty={:?}", result_ty);
diff --git a/src/librustc_typeck/check/_match.rs b/src/librustc_typeck/check/_match.rs
index fb139b5033b3b..9e23f5df3c6a8 100644
--- a/src/librustc_typeck/check/_match.rs
+++ b/src/librustc_typeck/check/_match.rs
@@ -105,7 +105,7 @@ impl<'a, 'tcx> FnCtxt<'a, 'tcx> {
                 && i != 0
                 && self.if_fallback_coercion(expr.span, &arms[0].body, &mut coercion)
             {
-                tcx.types.err
+                tcx.ty_error()
             } else {
                 // Only call this if this is not an `if` expr with an expected type and no `else`
                 // clause to avoid duplicated type errors. (#60254)
diff --git a/src/librustc_typeck/check/callee.rs b/src/librustc_typeck/check/callee.rs
index aa316105f7f11..13695be83a9da 100644
--- a/src/librustc_typeck/check/callee.rs
+++ b/src/librustc_typeck/check/callee.rs
@@ -383,7 +383,7 @@ impl<'a, 'tcx> FnCtxt<'a, 'tcx> {
                 (
                     ty::Binder::bind(self.tcx.mk_fn_sig(
                         self.err_args(arg_exprs.len()).into_iter(),
-                        self.tcx.types.err,
+                        self.tcx.ty_error(),
                         false,
                         hir::Unsafety::Normal,
                         abi::Abi::Rust,
diff --git a/src/librustc_typeck/check/cast.rs b/src/librustc_typeck/check/cast.rs
index 46d6706cbf429..78474dac76f67 100644
--- a/src/librustc_typeck/check/cast.rs
+++ b/src/librustc_typeck/check/cast.rs
@@ -43,6 +43,7 @@ use rustc_middle::ty::subst::SubstsRef;
 use rustc_middle::ty::{self, Ty, TypeAndMut, TypeFoldable};
 use rustc_session::lint;
 use rustc_session::Session;
+use rustc_span::symbol::sym;
 use rustc_span::Span;
 use rustc_trait_selection::traits;
 use rustc_trait_selection::traits::error_reporting::report_object_safety_error;
@@ -135,7 +136,7 @@ impl<'a, 'tcx> FnCtxt<'a, 'tcx> {
             | ty::Generator(..)
             | ty::Adt(..)
             | ty::Never
-            | ty::Error => {
+            | ty::Error(_) => {
                 self.tcx
                     .sess
                     .delay_span_bug(span, &format!("`{:?}` should be sized but is not?", t));
@@ -333,10 +334,11 @@ impl<'a, 'tcx> CastCheck<'tcx> {
                     "only `u8` can be cast as `char`, not `{}`",
                     self.expr_ty
                 )
+                .span_label(self.span, "invalid cast")
                 .emit();
             }
             CastError::NonScalar => {
-                type_error_struct!(
+                let mut err = type_error_struct!(
                     fcx.tcx.sess,
                     self.span,
                     self.expr_ty,
@@ -344,12 +346,75 @@ impl<'a, 'tcx> CastCheck<'tcx> {
                     "non-primitive cast: `{}` as `{}`",
                     self.expr_ty,
                     fcx.ty_to_string(self.cast_ty)
-                )
-                .note(
-                    "an `as` expression can only be used to convert between \
-                                         primitive types. Consider using the `From` trait",
-                )
-                .emit();
+                );
+                let mut sugg = None;
+                if let ty::Ref(reg, _, mutbl) = self.cast_ty.kind {
+                    if fcx
+                        .try_coerce(
+                            self.expr,
+                            fcx.tcx.mk_ref(reg, TypeAndMut { ty: self.expr_ty, mutbl }),
+                            self.cast_ty,
+                            AllowTwoPhase::No,
+                        )
+                        .is_ok()
+                    {
+                        sugg = Some(format!("&{}", mutbl.prefix_str()));
+                    }
+                }
+                if let Some(sugg) = sugg {
+                    err.span_label(self.span, "invalid cast");
+                    err.span_suggestion_verbose(
+                        self.expr.span.shrink_to_lo(),
+                        "borrow the value for the cast to be valid",
+                        sugg,
+                        Applicability::MachineApplicable,
+                    );
+                } else if !matches!(
+                    self.cast_ty.kind,
+                    ty::FnDef(..) | ty::FnPtr(..) | ty::Closure(..)
+                ) {
+                    let mut label = true;
+                    // Check `impl From<self.expr_ty> for self.cast_ty {}` for accurate suggestion:
+                    if let Ok(snippet) = fcx.tcx.sess.source_map().span_to_snippet(self.expr.span) {
+                        if let Some(from_trait) = fcx.tcx.get_diagnostic_item(sym::from_trait) {
+                            let ty = fcx.resolve_vars_if_possible(&self.cast_ty);
+                            // Erase regions to avoid panic in `prove_value` when calling
+                            // `type_implements_trait`.
+                            let ty = fcx.tcx.erase_regions(&ty);
+                            let expr_ty = fcx.resolve_vars_if_possible(&self.expr_ty);
+                            let expr_ty = fcx.tcx.erase_regions(&expr_ty);
+                            let ty_params = fcx.tcx.mk_substs_trait(expr_ty, &[]);
+                            // Check for infer types because cases like `Option<{integer}>` would
+                            // panic otherwise.
+                            if !expr_ty.has_infer_types()
+                                && fcx.tcx.type_implements_trait((
+                                    from_trait,
+                                    ty,
+                                    ty_params,
+                                    fcx.param_env,
+                                ))
+                            {
+                                label = false;
+                                err.span_suggestion(
+                                    self.span,
+                                    "consider using the `From` trait instead",
+                                    format!("{}::from({})", self.cast_ty, snippet),
+                                    Applicability::MaybeIncorrect,
+                                );
+                            }
+                        }
+                    }
+                    let msg = "an `as` expression can only be used to convert between primitive \
+                               types or to coerce to a specific trait object";
+                    if label {
+                        err.span_label(self.span, msg);
+                    } else {
+                        err.note(msg);
+                    }
+                } else {
+                    err.span_label(self.span, "invalid cast");
+                }
+                err.emit();
             }
             CastError::SizedUnsizedCast => {
                 use crate::structured_errors::{SizedUnsizedCastError, StructuredDiagnostic};
@@ -370,21 +435,22 @@ impl<'a, 'tcx> CastCheck<'tcx> {
                 };
                 let mut err = struct_span_err!(
                     fcx.tcx.sess,
-                    self.span,
+                    if unknown_cast_to { self.cast_span } else { self.span },
                     E0641,
                     "cannot cast {} a pointer of an unknown kind",
                     if unknown_cast_to { "to" } else { "from" }
                 );
-                err.note(
-                    "the type information given here is insufficient to check whether \
-                          the pointer cast is valid",
-                );
                 if unknown_cast_to {
-                    err.span_suggestion_short(
-                        self.cast_span,
-                        "consider giving more type information",
-                        String::new(),
-                        Applicability::Unspecified,
+                    err.span_label(self.cast_span, "needs more type information");
+                    err.note(
+                        "the type information given here is insufficient to check whether \
+                        the pointer cast is valid",
+                    );
+                } else {
+                    err.span_label(
+                        self.span,
+                        "the type information given here is insufficient to check whether \
+                        the pointer cast is valid",
                     );
                 }
                 err.emit();
@@ -438,13 +504,16 @@ impl<'a, 'tcx> CastCheck<'tcx> {
                     Ok(s) => {
                         err.span_suggestion(
                             self.cast_span,
-                            "try casting to a `Box` instead",
+                            "you can cast to a `Box` instead",
                             format!("Box<{}>", s),
                             Applicability::MachineApplicable,
                         );
                     }
                     Err(_) => {
-                        err.span_help(self.cast_span, &format!("did you mean `Box<{}>`?", tstr));
+                        err.span_help(
+                            self.cast_span,
+                            &format!("you might have meant `Box<{}>`", tstr),
+                        );
                     }
                 }
             }
diff --git a/src/librustc_typeck/check/closure.rs b/src/librustc_typeck/check/closure.rs
index 206619588c71d..6d09ddc925ffe 100644
--- a/src/librustc_typeck/check/closure.rs
+++ b/src/librustc_typeck/check/closure.rs
@@ -700,7 +700,7 @@ impl<'a, 'tcx> FnCtxt<'a, 'tcx> {
         let supplied_arguments = decl.inputs.iter().map(|a| {
             // Convert the types that the user supplied (if any), but ignore them.
             astconv.ast_ty_to_ty(a);
-            self.tcx.types.err
+            self.tcx.ty_error()
         });
 
         if let hir::FnRetTy::Return(ref output) = decl.output {
@@ -709,7 +709,7 @@ impl<'a, 'tcx> FnCtxt<'a, 'tcx> {
 
         let result = ty::Binder::bind(self.tcx.mk_fn_sig(
             supplied_arguments,
-            self.tcx.types.err,
+            self.tcx.ty_error(),
             decl.c_variadic,
             hir::Unsafety::Normal,
             Abi::RustCall,
diff --git a/src/librustc_typeck/check/coercion.rs b/src/librustc_typeck/check/coercion.rs
index 15ec92568fb4d..dd3f292fb5684 100644
--- a/src/librustc_typeck/check/coercion.rs
+++ b/src/librustc_typeck/check/coercion.rs
@@ -162,7 +162,7 @@ impl<'f, 'tcx> Coerce<'f, 'tcx> {
 
         // Just ignore error types.
         if a.references_error() || b.references_error() {
-            return success(vec![], self.fcx.tcx.types.err, vec![]);
+            return success(vec![], self.fcx.tcx.ty_error(), vec![]);
         }
 
         if a.is_never() {
@@ -864,7 +864,7 @@ impl<'a, 'tcx> FnCtxt<'a, 'tcx> {
 
         let (adjustments, _) = self.register_infer_ok_obligations(ok);
         self.apply_adjustments(expr, adjustments);
-        Ok(if expr_ty.references_error() { self.tcx.types.err } else { target })
+        Ok(if expr_ty.references_error() { self.tcx.ty_error() } else { target })
     }
 
     /// Same as `try_coerce()`, but without side-effects.
@@ -1239,7 +1239,7 @@ impl<'tcx, 'exprs, E: AsCoercionSite> CoerceMany<'tcx, 'exprs, E> {
         // If we see any error types, just propagate that error
         // upwards.
         if expression_ty.references_error() || self.merged_ty().references_error() {
-            self.final_ty = Some(fcx.tcx.types.err);
+            self.final_ty = Some(fcx.tcx.ty_error());
             return;
         }
 
@@ -1396,7 +1396,7 @@ impl<'tcx, 'exprs, E: AsCoercionSite> CoerceMany<'tcx, 'exprs, E> {
 
                 err.emit_unless(assign_to_bool || unsized_return);
 
-                self.final_ty = Some(fcx.tcx.types.err);
+                self.final_ty = Some(fcx.tcx.ty_error());
             }
         }
     }
diff --git a/src/librustc_typeck/check/expr.rs b/src/librustc_typeck/check/expr.rs
index bc3ef73d851eb..69cfafc21648f 100644
--- a/src/librustc_typeck/check/expr.rs
+++ b/src/librustc_typeck/check/expr.rs
@@ -248,7 +248,7 @@ impl<'a, 'tcx> FnCtxt<'a, 'tcx> {
                     tcx.types.never
                 } else {
                     // There was an error; make type-check fail.
-                    tcx.types.err
+                    tcx.ty_error()
                 }
             }
             ExprKind::Ret(ref expr_opt) => self.check_expr_return(expr_opt.as_deref(), expr),
@@ -284,7 +284,7 @@ impl<'a, 'tcx> FnCtxt<'a, 'tcx> {
             ExprKind::Field(ref base, field) => self.check_field(expr, needs, &base, field),
             ExprKind::Index(ref base, ref idx) => self.check_expr_index(base, idx, needs, expr),
             ExprKind::Yield(ref value, ref src) => self.check_expr_yield(value, expr, src),
-            hir::ExprKind::Err => tcx.types.err,
+            hir::ExprKind::Err => tcx.ty_error(),
         }
     }
 
@@ -360,7 +360,7 @@ impl<'a, 'tcx> FnCtxt<'a, 'tcx> {
                             tcx.sess.parse_sess.expr_parentheses_needed(&mut err, *sp, None);
                         }
                         err.emit();
-                        oprnd_t = tcx.types.err;
+                        oprnd_t = tcx.ty_error();
                     }
                 }
                 hir::UnOp::UnNot => {
@@ -410,7 +410,7 @@ impl<'a, 'tcx> FnCtxt<'a, 'tcx> {
 
         let tm = ty::TypeAndMut { ty, mutbl };
         match kind {
-            _ if tm.ty.references_error() => self.tcx.types.err,
+            _ if tm.ty.references_error() => self.tcx.ty_error(),
             hir::BorrowKind::Raw => {
                 self.check_named_place_expr(oprnd);
                 self.tcx.mk_ptr(tm)
@@ -476,11 +476,11 @@ impl<'a, 'tcx> FnCtxt<'a, 'tcx> {
         let ty = match res {
             Res::Err => {
                 self.set_tainted_by_errors();
-                tcx.types.err
+                tcx.ty_error()
             }
             Res::Def(DefKind::Ctor(_, CtorKind::Fictive), _) => {
                 report_unexpected_variant_res(tcx, res, expr.span);
-                tcx.types.err
+                tcx.ty_error()
             }
             _ => self.instantiate_value_path(segs, opt_ty, res, expr.span, expr.hir_id).0,
         };
@@ -560,11 +560,10 @@ impl<'a, 'tcx> FnCtxt<'a, 'tcx> {
                         Some(ctxt) => ctxt.coerce.as_ref().map(|coerce| coerce.expected_ty()),
                         None => {
                             // Avoid ICE when `break` is inside a closure (#65383).
-                            self.tcx.sess.delay_span_bug(
+                            return tcx.ty_error_with_message(
                                 expr.span,
                                 "break was outside loop, but no error was emitted",
                             );
-                            return tcx.types.err;
                         }
                     }
                 };
@@ -572,7 +571,7 @@ impl<'a, 'tcx> FnCtxt<'a, 'tcx> {
                 // If the loop context is not a `loop { }`, then break with
                 // a value is illegal, and `opt_coerce_to` will be `None`.
                 // Just set expectation to error in that case.
-                let coerce_to = opt_coerce_to.unwrap_or(tcx.types.err);
+                let coerce_to = opt_coerce_to.unwrap_or_else(|| tcx.ty_error());
 
                 // Recurse without `enclosing_breakables` borrowed.
                 e_ty = self.check_expr_with_hint(e, coerce_to);
@@ -592,11 +591,10 @@ impl<'a, 'tcx> FnCtxt<'a, 'tcx> {
                 Some(ctxt) => ctxt,
                 None => {
                     // Avoid ICE when `break` is inside a closure (#65383).
-                    self.tcx.sess.delay_span_bug(
+                    return tcx.ty_error_with_message(
                         expr.span,
                         "break was outside loop, but no error was emitted",
                     );
-                    return tcx.types.err;
                 }
             };
 
@@ -649,14 +647,15 @@ impl<'a, 'tcx> FnCtxt<'a, 'tcx> {
             // this can only happen if the `break` was not
             // inside a loop at all, which is caught by the
             // loop-checking pass.
-            self.tcx
-                .sess
-                .delay_span_bug(expr.span, "break was outside loop, but no error was emitted");
+            let err = self.tcx.ty_error_with_message(
+                expr.span,
+                "break was outside loop, but no error was emitted",
+            );
 
             // We still need to assign a type to the inner expression to
             // prevent the ICE in #43162.
             if let Some(ref e) = expr_opt {
-                self.check_expr_with_hint(e, tcx.types.err);
+                self.check_expr_with_hint(e, err);
 
                 // ... except when we try to 'break rust;'.
                 // ICE this expression in particular (see #43162).
@@ -666,8 +665,9 @@ impl<'a, 'tcx> FnCtxt<'a, 'tcx> {
                     }
                 }
             }
+
             // There was an error; make type-check fail.
-            tcx.types.err
+            err
         }
     }
 
@@ -803,7 +803,7 @@ impl<'a, 'tcx> FnCtxt<'a, 'tcx> {
         self.require_type_is_sized(lhs_ty, lhs.span, traits::AssignmentLhsSized);
 
         if lhs_ty.references_error() || rhs_ty.references_error() {
-            self.tcx.types.err
+            self.tcx.ty_error()
         } else {
             self.tcx.mk_unit()
         }
@@ -957,7 +957,7 @@ impl<'a, 'tcx> FnCtxt<'a, 'tcx> {
 
         // Eagerly check for some obvious errors.
         if t_expr.references_error() || t_cast.references_error() {
-            self.tcx.types.err
+            self.tcx.ty_error()
         } else {
             // Defer other checks until we're done type checking.
             let mut deferred_cast_checks = self.deferred_cast_checks.borrow_mut();
@@ -966,7 +966,7 @@ impl<'a, 'tcx> FnCtxt<'a, 'tcx> {
                     deferred_cast_checks.push(cast_check);
                     t_cast
                 }
-                Err(ErrorReported) => self.tcx.types.err,
+                Err(ErrorReported) => self.tcx.ty_error(),
             }
         }
     }
@@ -1041,7 +1041,7 @@ impl<'a, 'tcx> FnCtxt<'a, 'tcx> {
         };
 
         if element_ty.references_error() {
-            return tcx.types.err;
+            return tcx.ty_error();
         }
 
         tcx.mk_ty(ty::Array(t, count))
@@ -1071,7 +1071,7 @@ impl<'a, 'tcx> FnCtxt<'a, 'tcx> {
         });
         let tuple = self.tcx.mk_tup(elt_ts_iter);
         if tuple.references_error() {
-            self.tcx.types.err
+            self.tcx.ty_error()
         } else {
             self.require_type_is_sized(tuple, expr.span, traits::TupleInitializerSized);
             tuple
@@ -1092,7 +1092,7 @@ impl<'a, 'tcx> FnCtxt<'a, 'tcx> {
             variant_ty
         } else {
             self.check_struct_fields_on_error(fields, base_expr);
-            return self.tcx.types.err;
+            return self.tcx.ty_error();
         };
 
         let path_span = match *qpath {
@@ -1233,7 +1233,7 @@ impl<'a, 'tcx> FnCtxt<'a, 'tcx> {
                     self.report_unknown_field(adt_ty, variant, field, ast_fields, kind_name, span);
                 }
 
-                tcx.types.err
+                tcx.ty_error()
             };
 
             // Make sure to give a type to the field even if there's
@@ -1519,7 +1519,7 @@ impl<'a, 'tcx> FnCtxt<'a, 'tcx> {
             .emit();
         }
 
-        self.tcx().types.err
+        self.tcx().ty_error()
     }
 
     fn ban_nonexisting_field(
@@ -1775,7 +1775,7 @@ impl<'a, 'tcx> FnCtxt<'a, 'tcx> {
                         }
                     }
                     err.emit();
-                    self.tcx.types.err
+                    self.tcx.ty_error()
                 }
             }
         }
@@ -1887,7 +1887,7 @@ pub(super) fn ty_kind_suggestion(ty: Ty<'_>) -> Option<&'static str> {
         ty::Char => "'a'",
         ty::Int(_) | ty::Uint(_) => "42",
         ty::Float(_) => "3.14159",
-        ty::Error | ty::Never => return None,
+        ty::Error(_) | ty::Never => return None,
         _ => "value",
     })
 }
diff --git a/src/librustc_typeck/check/method/confirm.rs b/src/librustc_typeck/check/method/confirm.rs
index 007794ce1b7ff..8651c643cee87 100644
--- a/src/librustc_typeck/check/method/confirm.rs
+++ b/src/librustc_typeck/check/method/confirm.rs
@@ -141,11 +141,10 @@ impl<'a, 'tcx> ConfirmContext<'a, 'tcx> {
         let (_, n) = match autoderef.nth(pick.autoderefs) {
             Some(n) => n,
             None => {
-                self.tcx.sess.delay_span_bug(
+                return self.tcx.ty_error_with_message(
                     rustc_span::DUMMY_SP,
                     &format!("failed autoderef {}", pick.autoderefs),
                 );
-                return self.tcx.types.err;
             }
         };
         assert_eq!(n, pick.autoderefs);
diff --git a/src/librustc_typeck/check/method/probe.rs b/src/librustc_typeck/check/method/probe.rs
index 37652330108c9..93bcd5cf29149 100644
--- a/src/librustc_typeck/check/method/probe.rs
+++ b/src/librustc_typeck/check/method/probe.rs
@@ -400,7 +400,7 @@ impl<'a, 'tcx> FnCtxt<'a, 'tcx> {
                     .probe_instantiate_query_response(span, &orig_values, ty)
                     .unwrap_or_else(|_| span_bug!(span, "instantiating {:?} failed?", ty));
                 let ty = self.structurally_resolved_type(span, ty.value);
-                assert_eq!(ty, self.tcx.types.err);
+                assert!(matches!(ty.kind, ty::Error(_)));
                 return Err(MethodError::NoMatch(NoMatchData::new(
                     Vec::new(),
                     Vec::new(),
@@ -478,7 +478,7 @@ fn method_autoderef_steps<'tcx>(
 
         let final_ty = autoderef.maybe_ambiguous_final_ty();
         let opt_bad_ty = match final_ty.kind {
-            ty::Infer(ty::TyVar(_)) | ty::Error => Some(MethodAutoderefBadTy {
+            ty::Infer(ty::TyVar(_)) | ty::Error(_) => Some(MethodAutoderefBadTy {
                 reached_raw_pointer,
                 ty: infcx
                     .make_query_response_ignoring_pending_obligations(inference_vars, final_ty),
diff --git a/src/librustc_typeck/check/mod.rs b/src/librustc_typeck/check/mod.rs
index c26acd7a47703..b60b06567d6fa 100644
--- a/src/librustc_typeck/check/mod.rs
+++ b/src/librustc_typeck/check/mod.rs
@@ -138,6 +138,7 @@ use rustc_target::spec::abi::Abi;
 use rustc_trait_selection::infer::InferCtxtExt as _;
 use rustc_trait_selection::opaque_types::{InferCtxtExt as _, OpaqueTypeDecl};
 use rustc_trait_selection::traits::error_reporting::recursive_type_with_infinite_size_error;
+use rustc_trait_selection::traits::error_reporting::suggestions::ReturnsVisitor;
 use rustc_trait_selection::traits::error_reporting::InferCtxtExt as _;
 use rustc_trait_selection::traits::query::evaluate_obligation::InferCtxtExt as _;
 use rustc_trait_selection::traits::{
@@ -967,8 +968,7 @@ fn diagnostic_only_typeck_tables_of<'tcx>(
 ) -> &ty::TypeckTables<'tcx> {
     let fallback = move || {
         let span = tcx.hir().span(tcx.hir().as_local_hir_id(def_id));
-        tcx.sess.delay_span_bug(span, "diagnostic only typeck table used");
-        tcx.types.err
+        tcx.ty_error_with_message(span, "diagnostic only typeck table used")
     };
     typeck_tables_of_with_fallback(tcx, def_id, fallback)
 }
@@ -1711,6 +1711,173 @@ fn check_opaque_for_inheriting_lifetimes(tcx: TyCtxt<'tcx>, def_id: LocalDefId,
     }
 }
 
+/// Given a `DefId` for an opaque type in return position, find its parent item's return
+/// expressions.
+fn get_owner_return_paths(
+    tcx: TyCtxt<'tcx>,
+    def_id: LocalDefId,
+) -> Option<(hir::HirId, ReturnsVisitor<'tcx>)> {
+    let hir_id = tcx.hir().as_local_hir_id(def_id);
+    let id = tcx.hir().get_parent_item(hir_id);
+    tcx.hir()
+        .find(id)
+        .map(|n| (id, n))
+        .and_then(|(hir_id, node)| node.body_id().map(|b| (hir_id, b)))
+        .map(|(hir_id, body_id)| {
+            let body = tcx.hir().body(body_id);
+            let mut visitor = ReturnsVisitor::default();
+            visitor.visit_body(body);
+            (hir_id, visitor)
+        })
+}
+
+/// Emit an error for recursive opaque types.
+///
+/// If this is a return `impl Trait`, find the item's return expressions and point at them. For
+/// direct recursion this is enough, but for indirect recursion also point at the last intermediary
+/// `impl Trait`.
+///
+/// If all the return expressions evaluate to `!`, then we explain that the error will go away
+/// after changing it. This can happen when a user uses `panic!()` or similar as a placeholder.
+fn opaque_type_cycle_error(tcx: TyCtxt<'tcx>, def_id: LocalDefId, span: Span) {
+    let mut err = struct_span_err!(tcx.sess, span, E0720, "cannot resolve opaque type");
+
+    let mut label = false;
+    if let Some((hir_id, visitor)) = get_owner_return_paths(tcx, def_id) {
+        let tables = tcx.typeck_tables_of(tcx.hir().local_def_id(hir_id));
+        if visitor
+            .returns
+            .iter()
+            .filter_map(|expr| tables.node_type_opt(expr.hir_id))
+            .all(|ty| matches!(ty.kind, ty::Never))
+        {
+            let spans = visitor
+                .returns
+                .iter()
+                .filter(|expr| tables.node_type_opt(expr.hir_id).is_some())
+                .map(|expr| expr.span)
+                .collect::<Vec<Span>>();
+            let span_len = spans.len();
+            if span_len == 1 {
+                err.span_label(spans[0], "this returned value is of `!` type");
+            } else {
+                let mut multispan: MultiSpan = spans.clone().into();
+                for span in spans {
+                    multispan
+                        .push_span_label(span, "this returned value is of `!` type".to_string());
+                }
+                err.span_note(multispan, "these returned values have a concrete \"never\" type");
+            }
+            err.help("this error will resolve once the item's body returns a concrete type");
+        } else {
+            let mut seen = FxHashSet::default();
+            seen.insert(span);
+            err.span_label(span, "recursive opaque type");
+            label = true;
+            for (sp, ty) in visitor
+                .returns
+                .iter()
+                .filter_map(|e| tables.node_type_opt(e.hir_id).map(|t| (e.span, t)))
+                .filter(|(_, ty)| !matches!(ty.kind, ty::Never))
+            {
+                struct VisitTypes(Vec<DefId>);
+                impl<'tcx> ty::fold::TypeVisitor<'tcx> for VisitTypes {
+                    fn visit_ty(&mut self, t: Ty<'tcx>) -> bool {
+                        match t.kind {
+                            ty::Opaque(def, _) => {
+                                self.0.push(def);
+                                false
+                            }
+                            _ => t.super_visit_with(self),
+                        }
+                    }
+                }
+                let mut visitor = VisitTypes(vec![]);
+                ty.visit_with(&mut visitor);
+                for def_id in visitor.0 {
+                    let ty_span = tcx.def_span(def_id);
+                    if !seen.contains(&ty_span) {
+                        err.span_label(ty_span, &format!("returning this opaque type `{}`", ty));
+                        seen.insert(ty_span);
+                    }
+                    err.span_label(sp, &format!("returning here with type `{}`", ty));
+                }
+            }
+        }
+    }
+    if !label {
+        err.span_label(span, "cannot resolve opaque type");
+    }
+    err.emit();
+}
+
+/// Emit an error for recursive opaque types in a `let` binding.
+fn binding_opaque_type_cycle_error(
+    tcx: TyCtxt<'tcx>,
+    def_id: LocalDefId,
+    span: Span,
+    partially_expanded_type: Ty<'tcx>,
+) {
+    let mut err = struct_span_err!(tcx.sess, span, E0720, "cannot resolve opaque type");
+    err.span_label(span, "cannot resolve opaque type");
+    // Find the the owner that declared this `impl Trait` type.
+    let hir_id = tcx.hir().as_local_hir_id(def_id);
+    let mut prev_hir_id = hir_id;
+    let mut hir_id = tcx.hir().get_parent_node(hir_id);
+    while let Some(node) = tcx.hir().find(hir_id) {
+        match node {
+            hir::Node::Local(hir::Local {
+                pat,
+                init: None,
+                ty: Some(ty),
+                source: hir::LocalSource::Normal,
+                ..
+            }) => {
+                err.span_label(pat.span, "this binding might not have a concrete type");
+                err.span_suggestion_verbose(
+                    ty.span.shrink_to_hi(),
+                    "set the binding to a value for a concrete type to be resolved",
+                    " = /* value */".to_string(),
+                    Applicability::HasPlaceholders,
+                );
+            }
+            hir::Node::Local(hir::Local {
+                init: Some(expr),
+                source: hir::LocalSource::Normal,
+                ..
+            }) => {
+                let hir_id = tcx.hir().as_local_hir_id(def_id);
+                let tables =
+                    tcx.typeck_tables_of(tcx.hir().local_def_id(tcx.hir().get_parent_item(hir_id)));
+                if let Some(ty) = tables.node_type_opt(expr.hir_id) {
+                    err.span_label(
+                        expr.span,
+                        &format!(
+                            "this is of type `{}`, which doesn't constrain \
+                             `{}` enough to arrive to a concrete type",
+                            ty, partially_expanded_type
+                        ),
+                    );
+                }
+            }
+            _ => {}
+        }
+        if prev_hir_id == hir_id {
+            break;
+        }
+        prev_hir_id = hir_id;
+        hir_id = tcx.hir().get_parent_node(hir_id);
+    }
+    err.emit();
+}
+
+fn async_opaque_type_cycle_error(tcx: TyCtxt<'tcx>, span: Span) {
+    struct_span_err!(tcx.sess, span, E0733, "recursion in an `async fn` requires boxing")
+        .span_label(span, "recursive `async fn`")
+        .note("a recursive `async fn` must be rewritten to return a boxed `dyn Future`")
+        .emit();
+}
+
 /// Checks that an opaque type does not contain cycles.
 fn check_opaque_for_cycles<'tcx>(
     tcx: TyCtxt<'tcx>,
@@ -1721,21 +1888,12 @@ fn check_opaque_for_cycles<'tcx>(
 ) {
     if let Err(partially_expanded_type) = tcx.try_expand_impl_trait_type(def_id.to_def_id(), substs)
     {
-        if let hir::OpaqueTyOrigin::AsyncFn = origin {
-            struct_span_err!(tcx.sess, span, E0733, "recursion in an `async fn` requires boxing",)
-                .span_label(span, "recursive `async fn`")
-                .note("a recursive `async fn` must be rewritten to return a boxed `dyn Future`")
-                .emit();
-        } else {
-            let mut err =
-                struct_span_err!(tcx.sess, span, E0720, "opaque type expands to a recursive type",);
-            err.span_label(span, "expands to a recursive type");
-            if let ty::Opaque(..) = partially_expanded_type.kind {
-                err.note("type resolves to itself");
-            } else {
-                err.note(&format!("expanded type is `{}`", partially_expanded_type));
+        match origin {
+            hir::OpaqueTyOrigin::AsyncFn => async_opaque_type_cycle_error(tcx, span),
+            hir::OpaqueTyOrigin::Binding => {
+                binding_opaque_type_cycle_error(tcx, def_id, span, partially_expanded_type)
             }
-            err.emit();
+            _ => opaque_type_cycle_error(tcx, def_id, span),
         }
     }
 }
@@ -3387,7 +3545,7 @@ impl<'a, 'tcx> FnCtxt<'a, 'tcx> {
     pub fn node_ty(&self, id: hir::HirId) -> Ty<'tcx> {
         match self.tables.borrow().node_types().get(id) {
             Some(&t) => t,
-            None if self.is_tainted_by_errors() => self.tcx.types.err,
+            None if self.is_tainted_by_errors() => self.tcx.ty_error(),
             None => {
                 bug!(
                     "no type for node {}: {} in fcx {}",
@@ -3501,7 +3659,7 @@ impl<'a, 'tcx> FnCtxt<'a, 'tcx> {
 
         assert!(ty.is_ty_infer());
         let fallback = match self.type_is_unconstrained_numeric(ty) {
-            _ if self.is_tainted_by_errors() => self.tcx().types.err,
+            _ if self.is_tainted_by_errors() => self.tcx().ty_error(),
             UnconstrainedInt => self.tcx.types.i32,
             UnconstrainedFloat => self.tcx.types.f64,
             Neither if self.type_var_diverges(ty) => self.tcx.mk_diverging_default(),
@@ -3774,7 +3932,7 @@ impl<'a, 'tcx> FnCtxt<'a, 'tcx> {
                 tuple_arguments,
                 None,
             );
-            return self.tcx.types.err;
+            return self.tcx.ty_error();
         }
 
         let method = method.unwrap();
@@ -4161,7 +4319,7 @@ impl<'a, 'tcx> FnCtxt<'a, 'tcx> {
     }
 
     fn err_args(&self, len: usize) -> Vec<Ty<'tcx>> {
-        vec![self.tcx.types.err; len]
+        vec![self.tcx.ty_error(); len]
     }
 
     /// Given a vec of evaluated `FulfillmentError`s and an `fn` call argument expressions, we walk
@@ -4305,7 +4463,7 @@ impl<'a, 'tcx> FnCtxt<'a, 'tcx> {
                 opt_ty.unwrap_or_else(|| self.next_float_var())
             }
             ast::LitKind::Bool(_) => tcx.types.bool,
-            ast::LitKind::Err(_) => tcx.types.err,
+            ast::LitKind::Err(_) => tcx.ty_error(),
         }
     }
 
@@ -4442,7 +4600,7 @@ impl<'a, 'tcx> FnCtxt<'a, 'tcx> {
                 };
                 let result =
                     AstConv::associated_path_to_ty(self, hir_id, path_span, ty, res, segment, true);
-                let ty = result.map(|(ty, _, _)| ty).unwrap_or(self.tcx().types.err);
+                let ty = result.map(|(ty, _, _)| ty).unwrap_or_else(|_| self.tcx().ty_error());
                 let result = result.map(|(_, kind, def_id)| (kind, def_id));
 
                 // Write back the new resolution.
@@ -4570,7 +4728,7 @@ impl<'a, 'tcx> FnCtxt<'a, 'tcx> {
         ty: Ty<'tcx>,
     ) {
         if ty.references_error() {
-            // Override the types everywhere with `types.err` to avoid knock on errors.
+            // Override the types everywhere with `err()` to avoid knock on errors.
             self.write_ty(local.hir_id, ty);
             self.write_ty(local.pat.hir_id, ty);
             let local_ty = LocalTy { decl_ty, revealed_ty: ty };
@@ -4790,7 +4948,7 @@ impl<'a, 'tcx> FnCtxt<'a, 'tcx> {
         let mut ty = ctxt.coerce.unwrap().complete(self);
 
         if self.has_errors.get() || ty.references_error() {
-            ty = self.tcx.types.err
+            ty = self.tcx.ty_error()
         }
 
         self.write_ty(blk.hir_id, ty);
@@ -5378,7 +5536,7 @@ impl<'a, 'tcx> FnCtxt<'a, 'tcx> {
             _ => return None,
         };
         let last_expr_ty = self.node_ty(last_expr.hir_id);
-        if matches!(last_expr_ty.kind, ty::Error)
+        if matches!(last_expr_ty.kind, ty::Error(_))
             || self.can_sub(self.param_env, last_expr_ty, expected_ty).is_err()
         {
             return None;
@@ -5538,7 +5696,7 @@ impl<'a, 'tcx> FnCtxt<'a, 'tcx> {
                     }
                     err.emit();
 
-                    return (tcx.types.err, res);
+                    return (tcx.ty_error(), res);
                 }
             }
         } else {
@@ -5731,8 +5889,9 @@ impl<'a, 'tcx> FnCtxt<'a, 'tcx> {
                     .note("type must be known at this point")
                     .emit();
             }
-            self.demand_suptype(sp, self.tcx.types.err, ty);
-            self.tcx.types.err
+            let err = self.tcx.ty_error();
+            self.demand_suptype(sp, err, ty);
+            err
         }
     }
 
diff --git a/src/librustc_typeck/check/op.rs b/src/librustc_typeck/check/op.rs
index a3a27dc138be9..fe50870911647 100644
--- a/src/librustc_typeck/check/op.rs
+++ b/src/librustc_typeck/check/op.rs
@@ -497,7 +497,7 @@ impl<'a, 'tcx> FnCtxt<'a, 'tcx> {
                         }
                     }
                 }
-                self.tcx.types.err
+                self.tcx.ty_error()
             }
         };
 
@@ -709,7 +709,7 @@ impl<'a, 'tcx> FnCtxt<'a, 'tcx> {
                     }
                     err.emit();
                 }
-                self.tcx.types.err
+                self.tcx.ty_error()
             }
         }
     }
diff --git a/src/librustc_typeck/check/pat.rs b/src/librustc_typeck/check/pat.rs
index 8a10427260eee..7965c9c9ce12a 100644
--- a/src/librustc_typeck/check/pat.rs
+++ b/src/librustc_typeck/check/pat.rs
@@ -442,7 +442,7 @@ impl<'a, 'tcx> FnCtxt<'a, 'tcx> {
             // There exists a side that didn't meet our criteria that the end-point
             // be of a numeric or char type, as checked in `calc_side` above.
             self.emit_err_pat_range(span, lhs, rhs);
-            return self.tcx.types.err;
+            return self.tcx.ty_error();
         }
 
         // Now that we know the types can be unified we find the unified type
@@ -673,11 +673,12 @@ impl<'a, 'tcx> FnCtxt<'a, 'tcx> {
         {
             variant_ty
         } else {
+            let err = self.tcx.ty_error();
             for field in fields {
                 let ti = TopInfo { parent_pat: Some(&pat), ..ti };
-                self.check_pat(&field.pat, self.tcx.types.err, def_bm, ti);
+                self.check_pat(&field.pat, err, def_bm, ti);
             }
-            return self.tcx.types.err;
+            return err;
         };
 
         // Type-check the path.
@@ -687,7 +688,7 @@ impl<'a, 'tcx> FnCtxt<'a, 'tcx> {
         if self.check_struct_pat_fields(pat_ty, &pat, variant, fields, etc, def_bm, ti) {
             pat_ty
         } else {
-            self.tcx.types.err
+            self.tcx.ty_error()
         }
     }
 
@@ -705,11 +706,11 @@ impl<'a, 'tcx> FnCtxt<'a, 'tcx> {
         match res {
             Res::Err => {
                 self.set_tainted_by_errors();
-                return tcx.types.err;
+                return tcx.ty_error();
             }
             Res::Def(DefKind::AssocFn | DefKind::Ctor(_, CtorKind::Fictive | CtorKind::Fn), _) => {
                 report_unexpected_variant_res(tcx, res, pat.span);
-                return tcx.types.err;
+                return tcx.ty_error();
             }
             Res::SelfCtor(..)
             | Res::Def(
@@ -788,7 +789,7 @@ impl<'a, 'tcx> FnCtxt<'a, 'tcx> {
         let on_error = || {
             let parent_pat = Some(pat);
             for pat in subpats {
-                self.check_pat(&pat, tcx.types.err, def_bm, TopInfo { parent_pat, ..ti });
+                self.check_pat(&pat, tcx.ty_error(), def_bm, TopInfo { parent_pat, ..ti });
             }
         };
         let report_unexpected_res = |res: Res| {
@@ -824,7 +825,7 @@ impl<'a, 'tcx> FnCtxt<'a, 'tcx> {
         if res == Res::Err {
             self.set_tainted_by_errors();
             on_error();
-            return self.tcx.types.err;
+            return self.tcx.ty_error();
         }
 
         // Type-check the path.
@@ -832,18 +833,18 @@ impl<'a, 'tcx> FnCtxt<'a, 'tcx> {
             self.instantiate_value_path(segments, opt_ty, res, pat.span, pat.hir_id);
         if !pat_ty.is_fn() {
             report_unexpected_res(res);
-            return tcx.types.err;
+            return tcx.ty_error();
         }
 
         let variant = match res {
             Res::Err => {
                 self.set_tainted_by_errors();
                 on_error();
-                return tcx.types.err;
+                return tcx.ty_error();
             }
             Res::Def(DefKind::AssocConst | DefKind::AssocFn, _) => {
                 report_unexpected_res(res);
-                return tcx.types.err;
+                return tcx.ty_error();
             }
             Res::Def(DefKind::Ctor(_, CtorKind::Fn), _) => tcx.expect_variant_res(res),
             _ => bug!("unexpected pattern resolution: {:?}", res),
@@ -880,7 +881,7 @@ impl<'a, 'tcx> FnCtxt<'a, 'tcx> {
             // Pattern has wrong number of fields.
             self.e0023(pat.span, res, qpath, subpats, &variant.fields, expected, had_err);
             on_error();
-            return tcx.types.err;
+            return tcx.ty_error();
         }
         pat_ty
     }
@@ -1001,9 +1002,9 @@ impl<'a, 'tcx> FnCtxt<'a, 'tcx> {
             err.emit();
             // Walk subpatterns with an expected type of `err` in this case to silence
             // further errors being emitted when using the bindings. #50333
-            let element_tys_iter = (0..max_len).map(|_| tcx.types.err);
+            let element_tys_iter = (0..max_len).map(|_| tcx.ty_error());
             for (_, elem) in elements.iter().enumerate_and_adjust(max_len, ddpos) {
-                self.check_pat(elem, &tcx.types.err, def_bm, ti);
+                self.check_pat(elem, &tcx.ty_error(), def_bm, ti);
             }
             tcx.mk_tup(element_tys_iter)
         } else {
@@ -1052,7 +1053,7 @@ impl<'a, 'tcx> FnCtxt<'a, 'tcx> {
                 Occupied(occupied) => {
                     self.error_field_already_bound(span, field.ident, *occupied.get());
                     no_field_errors = false;
-                    tcx.types.err
+                    tcx.ty_error()
                 }
                 Vacant(vacant) => {
                     vacant.insert(span);
@@ -1066,7 +1067,7 @@ impl<'a, 'tcx> FnCtxt<'a, 'tcx> {
                         .unwrap_or_else(|| {
                             inexistent_fields.push(field.ident);
                             no_field_errors = false;
-                            tcx.types.err
+                            tcx.ty_error()
                         })
                 }
             };
@@ -1281,7 +1282,8 @@ impl<'a, 'tcx> FnCtxt<'a, 'tcx> {
             self.demand_eqtype_pat(span, expected, box_ty, ti);
             (box_ty, inner_ty)
         } else {
-            (tcx.types.err, tcx.types.err)
+            let err = tcx.ty_error();
+            (err, err)
         };
         self.check_pat(&inner, inner_ty, def_bm, ti);
         box_ty
@@ -1327,7 +1329,8 @@ impl<'a, 'tcx> FnCtxt<'a, 'tcx> {
                 }
             }
         } else {
-            (tcx.types.err, tcx.types.err)
+            let err = tcx.ty_error();
+            (err, err)
         };
         self.check_pat(&inner, inner_ty, def_bm, TopInfo { parent_pat: Some(&pat), ..ti });
         rptr_ty
@@ -1378,7 +1381,7 @@ impl<'a, 'tcx> FnCtxt<'a, 'tcx> {
                 if !expected.references_error() {
                     self.error_expected_array_or_slice(span, expected);
                 }
-                let err = self.tcx.types.err;
+                let err = self.tcx.ty_error();
                 (err, Some(err), err)
             }
         };
@@ -1445,7 +1448,7 @@ impl<'a, 'tcx> FnCtxt<'a, 'tcx> {
         }
 
         // If we get here, we must have emitted an error.
-        (Some(self.tcx.types.err), arr_ty)
+        (Some(self.tcx.ty_error()), arr_ty)
     }
 
     fn error_scrutinee_inconsistent_length(&self, span: Span, min_len: u64, size: u64) {
diff --git a/src/librustc_typeck/check/upvar.rs b/src/librustc_typeck/check/upvar.rs
index 19a23e5a59478..8403c99f01bb5 100644
--- a/src/librustc_typeck/check/upvar.rs
+++ b/src/librustc_typeck/check/upvar.rs
@@ -91,7 +91,7 @@ impl<'a, 'tcx> FnCtxt<'a, 'tcx> {
         let (closure_def_id, substs) = match ty.kind {
             ty::Closure(def_id, substs) => (def_id, UpvarSubsts::Closure(substs)),
             ty::Generator(def_id, substs, _) => (def_id, UpvarSubsts::Generator(substs)),
-            ty::Error => {
+            ty::Error(_) => {
                 // #51714: skip analysis when we have already encountered type errors
                 return;
             }
diff --git a/src/librustc_typeck/check/writeback.rs b/src/librustc_typeck/check/writeback.rs
index 159d3d7a538a6..ba806430f17fd 100644
--- a/src/librustc_typeck/check/writeback.rs
+++ b/src/librustc_typeck/check/writeback.rs
@@ -208,11 +208,10 @@ impl<'cx, 'tcx> WritebackCx<'cx, 'tcx> {
                     // to access an unexistend index. We assume that more relevant errors will
                     // already have been emitted, so we only gate on this with an ICE if no
                     // error has been emitted. (#64638)
-                    self.tcx().sess.delay_span_bug(
+                    self.fcx.tcx.ty_error_with_message(
                         e.span,
                         &format!("bad index {:?} for base: `{:?}`", index, base),
-                    );
-                    self.fcx.tcx.types.err
+                    )
                 });
                 let index_ty = self.fcx.resolve_vars_if_possible(&index_ty);
 
@@ -681,7 +680,7 @@ impl<'cx, 'tcx> TypeFolder<'tcx> for Resolver<'cx, 'tcx> {
                 debug!("Resolver::fold_ty: input type `{:?}` not fully resolvable", t);
                 self.report_type_error(t);
                 self.replaced_with_error = true;
-                self.tcx().types.err
+                self.tcx().ty_error()
             }
         }
     }
@@ -698,7 +697,7 @@ impl<'cx, 'tcx> TypeFolder<'tcx> for Resolver<'cx, 'tcx> {
                 debug!("Resolver::fold_const: input const `{:?}` not fully resolvable", ct);
                 self.report_const_error(ct);
                 self.replaced_with_error = true;
-                self.tcx().mk_const(ty::Const { val: ty::ConstKind::Error, ty: ct.ty })
+                self.tcx().const_error(ct.ty)
             }
         }
     }
diff --git a/src/librustc_typeck/coherence/builtin.rs b/src/librustc_typeck/coherence/builtin.rs
index c5dd314dc6558..8c6161a626473 100644
--- a/src/librustc_typeck/coherence/builtin.rs
+++ b/src/librustc_typeck/coherence/builtin.rs
@@ -50,7 +50,7 @@ impl<'tcx> Checker<'tcx> {
 
 fn visit_implementation_of_drop(tcx: TyCtxt<'_>, impl_did: LocalDefId) {
     // Destructors only work on nominal types.
-    if let ty::Adt(..) | ty::Error = tcx.type_of(impl_did).kind {
+    if let ty::Adt(..) | ty::Error(_) = tcx.type_of(impl_did).kind {
         return;
     }
 
diff --git a/src/librustc_typeck/coherence/inherent_impls.rs b/src/librustc_typeck/coherence/inherent_impls.rs
index 653b7b8f2a5ba..93ee87f6c572e 100644
--- a/src/librustc_typeck/coherence/inherent_impls.rs
+++ b/src/librustc_typeck/coherence/inherent_impls.rs
@@ -296,7 +296,7 @@ impl ItemLikeVisitor<'v> for InherentCollect<'tcx> {
                     item.span,
                 );
             }
-            ty::Error => {}
+            ty::Error(_) => {}
             _ => {
                 struct_span_err!(
                     self.tcx.sess,
diff --git a/src/librustc_typeck/collect.rs b/src/librustc_typeck/collect.rs
index 1d59d749634ee..3bd75095bb602 100644
--- a/src/librustc_typeck/collect.rs
+++ b/src/librustc_typeck/collect.rs
@@ -307,8 +307,7 @@ impl AstConv<'tcx> for ItemCtxt<'tcx> {
     }
 
     fn ty_infer(&self, _: Option<&ty::GenericParamDef>, span: Span) -> Ty<'tcx> {
-        self.tcx().sess.delay_span_bug(span, "bad placeholder type");
-        self.tcx().types.err
+        self.tcx().ty_error_with_message(span, "bad_placeholder_type")
     }
 
     fn ct_infer(
@@ -318,8 +317,7 @@ impl AstConv<'tcx> for ItemCtxt<'tcx> {
         span: Span,
     ) -> &'tcx Const<'tcx> {
         bad_placeholder_type(self.tcx(), vec![span]).emit();
-
-        self.tcx().mk_const(ty::Const { val: ty::ConstKind::Error, ty })
+        self.tcx().const_error(ty)
     }
 
     fn projected_ty_from_poly_trait_ref(
@@ -419,7 +417,7 @@ impl AstConv<'tcx> for ItemCtxt<'tcx> {
                 _ => {}
             }
             err.emit();
-            self.tcx().types.err
+            self.tcx().ty_error()
         }
     }
 
@@ -1465,7 +1463,7 @@ fn fn_sig(tcx: TyCtxt<'_>, def_id: DefId) -> ty::PolyFnSig<'_> {
                     visitor.visit_ty(ty);
                     let mut diag = bad_placeholder_type(tcx, visitor.0);
                     let ret_ty = fn_sig.output();
-                    if ret_ty != tcx.types.err {
+                    if ret_ty != tcx.ty_error() {
                         diag.span_suggestion(
                             ty.span,
                             "replace with the correct return type",
@@ -2004,12 +2002,11 @@ fn associated_item_predicates(
             // once they are handled by the trait system.
             ty::GenericParamDefKind::Type { .. } => {
                 unimplemented_error("type");
-                tcx.types.err.into()
+                tcx.ty_error().into()
             }
             ty::GenericParamDefKind::Const => {
                 unimplemented_error("const");
-                tcx.mk_const(ty::Const { val: ty::ConstKind::Error, ty: tcx.type_of(param.def_id) })
-                    .into()
+                tcx.const_error(tcx.type_of(param.def_id)).into()
             }
         }
     };
diff --git a/src/librustc_typeck/collect/type_of.rs b/src/librustc_typeck/collect/type_of.rs
index 549a20531e299..cf5f2ec69d8d8 100644
--- a/src/librustc_typeck/collect/type_of.rs
+++ b/src/librustc_typeck/collect/type_of.rs
@@ -127,7 +127,7 @@ pub(super) fn type_of(tcx: TyCtxt<'_>, def_id: DefId) -> Ty<'_> {
                                 // Some error in the
                                 // owner fn prevented us from populating
                                 // the `concrete_opaque_types` table.
-                                tcx.types.err
+                                tcx.ty_error()
                             } else {
                                 // We failed to resolve the opaque type or it
                                 // resolves to itself. Return the non-revealed
@@ -217,11 +217,10 @@ pub(super) fn type_of(tcx: TyCtxt<'_>, def_id: DefId) -> Ty<'_> {
                         })
                         | Node::TraitRef(&TraitRef { path, .. }) => &*path,
                         _ => {
-                            tcx.sess.delay_span_bug(
+                            return tcx.ty_error_with_message(
                                 DUMMY_SP,
                                 &format!("unexpected const parent path {:?}", parent_node),
                             );
-                            return tcx.types.err;
                         }
                     };
 
@@ -254,14 +253,13 @@ pub(super) fn type_of(tcx: TyCtxt<'_>, def_id: DefId) -> Ty<'_> {
                         }
                         Res::Def(_, def_id) => tcx.generics_of(def_id),
                         res => {
-                            tcx.sess.delay_span_bug(
+                            return tcx.ty_error_with_message(
                                 DUMMY_SP,
                                 &format!(
                                     "unexpected anon const res {:?} in path: {:?}",
                                     res, path,
                                 ),
-                            );
-                            return tcx.types.err;
+                                );
                         }
                     };
 
@@ -283,24 +281,21 @@ pub(super) fn type_of(tcx: TyCtxt<'_>, def_id: DefId) -> Ty<'_> {
                     } else {
                         // This is no generic parameter associated with the arg. This is
                         // probably from an extra arg where one is not needed.
-                        tcx.sess.delay_span_bug(
+                        tcx.ty_error_with_message(
                             DUMMY_SP,
                             &format!(
-                                "missing generic parameter for `AnonConst`, parent: {:?}, res: {:?}",
+                                "missing generic parameter for `AnonConst`, \
+                                 parent: {:?}, res: {:?}",
                                 parent_node, res
                             ),
-                        );
-                        tcx.types.err
+                        )
                     }
                 }
 
-                x => {
-                    tcx.sess.delay_span_bug(
-                        DUMMY_SP,
-                        &format!("unexpected const parent in type_of_def_id(): {:?}", x),
-                    );
-                    tcx.types.err
-                }
+                x => tcx.ty_error_with_message(
+                    DUMMY_SP,
+                    &format!("unexpected const parent in type_of_def_id(): {:?}", x),
+                ),
             }
         }
 
@@ -568,7 +563,7 @@ fn find_opaque_ty_constraints(tcx: TyCtxt<'_>, def_id: LocalDefId) -> Ty<'_> {
         None => {
             let span = tcx.def_span(def_id);
             tcx.sess.span_err(span, "could not find defining uses");
-            tcx.types.err
+            tcx.ty_error()
         }
     }
 }
@@ -605,7 +600,7 @@ fn let_position_impl_trait_type(tcx: TyCtxt<'_>, opaque_ty_id: LocalDefId) -> Ty
             if let Some(ErrorReported) = owner_tables.tainted_by_errors {
                 // Some error in the owner fn prevented us from populating the
                 // `concrete_opaque_types` table.
-                tcx.types.err
+                tcx.ty_error()
             } else {
                 // We failed to resolve the opaque type or it resolves to
                 // itself. Return the non-revealed type, which should result in
@@ -655,7 +650,7 @@ fn infer_placeholder_type(
         }
         None => {
             let mut diag = bad_placeholder_type(tcx, vec![span]);
-            if ty != tcx.types.err {
+            if !matches!(ty.kind, ty::Error(_)) {
                 diag.span_suggestion(
                     span,
                     "replace `_` with the correct type",
diff --git a/src/librustc_typeck/variance/constraints.rs b/src/librustc_typeck/variance/constraints.rs
index eee0f764373a4..cae09267994e3 100644
--- a/src/librustc_typeck/variance/constraints.rs
+++ b/src/librustc_typeck/variance/constraints.rs
@@ -339,7 +339,7 @@ impl<'a, 'tcx> ConstraintContext<'a, 'tcx> {
                 self.add_constraints_from_sig(current, sig, variance);
             }
 
-            ty::Error => {
+            ty::Error(_) => {
                 // we encounter this when walking the trait references for object
                 // types, where we use Error as the Self type
             }
diff --git a/src/librustdoc/clean/mod.rs b/src/librustdoc/clean/mod.rs
index adb2ae9a5d660..73fe87b05d477 100644
--- a/src/librustdoc/clean/mod.rs
+++ b/src/librustdoc/clean/mod.rs
@@ -1717,7 +1717,7 @@ impl<'tcx> Clean<Type> for Ty<'tcx> {
             ty::Placeholder(..) => panic!("Placeholder"),
             ty::GeneratorWitness(..) => panic!("GeneratorWitness"),
             ty::Infer(..) => panic!("Infer"),
-            ty::Error => panic!("Error"),
+            ty::Error(_) => panic!("Error"),
         }
     }
 }
diff --git a/src/librustdoc/html/markdown.rs b/src/librustdoc/html/markdown.rs
index c129e54c0f28a..7a6626766d388 100644
--- a/src/librustdoc/html/markdown.rs
+++ b/src/librustdoc/html/markdown.rs
@@ -192,6 +192,7 @@ impl<'a, I: Iterator<Item = Event<'a>>> Iterator for CodeBlocks<'_, 'a, I> {
     fn next(&mut self) -> Option<Self::Item> {
         let event = self.inner.next();
         let compile_fail;
+        let should_panic;
         let ignore;
         let edition;
         if let Some(Event::Start(Tag::CodeBlock(kind))) = event {
@@ -205,6 +206,7 @@ impl<'a, I: Iterator<Item = Event<'a>>> Iterator for CodeBlocks<'_, 'a, I> {
                 return Some(Event::Start(Tag::CodeBlock(kind)));
             }
             compile_fail = parse_result.compile_fail;
+            should_panic = parse_result.should_panic;
             ignore = parse_result.ignore;
             edition = parse_result.edition;
         } else {
@@ -280,6 +282,8 @@ impl<'a, I: Iterator<Item = Event<'a>>> Iterator for CodeBlocks<'_, 'a, I> {
             Some(("This example is not tested".to_owned(), "ignore"))
         } else if compile_fail {
             Some(("This example deliberately fails to compile".to_owned(), "compile_fail"))
+        } else if should_panic {
+            Some(("This example panics".to_owned(), "should_panic"))
         } else if explicit_edition {
             Some((format!("This code runs with edition {}", edition), "edition"))
         } else {
@@ -295,6 +299,8 @@ impl<'a, I: Iterator<Item = Event<'a>>> Iterator for CodeBlocks<'_, 'a, I> {
                         " ignore"
                     } else if compile_fail {
                         " compile_fail"
+                    } else if should_panic {
+                        " should_panic"
                     } else if explicit_edition {
                         " edition "
                     } else {
@@ -314,6 +320,8 @@ impl<'a, I: Iterator<Item = Event<'a>>> Iterator for CodeBlocks<'_, 'a, I> {
                         " ignore"
                     } else if compile_fail {
                         " compile_fail"
+                    } else if should_panic {
+                        " should_panic"
                     } else if explicit_edition {
                         " edition "
                     } else {
diff --git a/src/librustdoc/html/static/main.js b/src/librustdoc/html/static/main.js
index 953f61a3772dc..8d53b05795374 100644
--- a/src/librustdoc/html/static/main.js
+++ b/src/librustdoc/html/static/main.js
@@ -100,6 +100,8 @@ function defocusSearchBar() {
     // 2 for "In Return Types"
     var currentTab = 0;
 
+    var mouseMovedAfterSearch = true;
+
     var titleBeforeSearch = document.title;
 
     function clearInputTimeout() {
@@ -162,6 +164,7 @@ function defocusSearchBar() {
         }
         addClass(main, "hidden");
         removeClass(search, "hidden");
+        mouseMovedAfterSearch = false;
     }
 
     function hideSearchResults(search) {
@@ -424,6 +427,12 @@ function defocusSearchBar() {
     document.addEventListener("keypress", handleShortcut);
     document.addEventListener("keydown", handleShortcut);
 
+    function resetMouseMoved(ev) {
+        mouseMovedAfterSearch = true;
+    }
+
+    document.addEventListener("mousemove", resetMouseMoved);
+
     var handleSourceHighlight = (function() {
         var prev_line_id = 0;
 
@@ -1353,20 +1362,22 @@ function defocusSearchBar() {
                 }
             };
             var mouseover_func = function(e) {
-                var el = e.target;
-                // to retrieve the real "owner" of the event.
-                while (el.tagName !== "TR") {
-                    el = el.parentNode;
-                }
-                clearTimeout(hoverTimeout);
-                hoverTimeout = setTimeout(function() {
-                    onEachLazy(document.getElementsByClassName("search-results"), function(e) {
-                        onEachLazy(e.getElementsByClassName("result"), function(i_e) {
-                            removeClass(i_e, "highlighted");
+                if (mouseMovedAfterSearch) {
+                    var el = e.target;
+                    // to retrieve the real "owner" of the event.
+                    while (el.tagName !== "TR") {
+                        el = el.parentNode;
+                    }
+                    clearTimeout(hoverTimeout);
+                    hoverTimeout = setTimeout(function() {
+                        onEachLazy(document.getElementsByClassName("search-results"), function(e) {
+                            onEachLazy(e.getElementsByClassName("result"), function(i_e) {
+                                removeClass(i_e, "highlighted");
+                            });
                         });
-                    });
-                    addClass(el, "highlighted");
-                }, 20);
+                        addClass(el, "highlighted");
+                    }, 20);
+                }
             };
             onEachLazy(document.getElementsByClassName("search-results"), function(e) {
                 onEachLazy(e.getElementsByClassName("result"), function(i_e) {
diff --git a/src/librustdoc/html/static/rustdoc.css b/src/librustdoc/html/static/rustdoc.css
index 2cb3347135c1b..9c6dd25394db0 100644
--- a/src/librustdoc/html/static/rustdoc.css
+++ b/src/librustdoc/html/static/rustdoc.css
@@ -1089,7 +1089,7 @@ h3 > .collapse-toggle, h4 > .collapse-toggle {
 	border-style: solid;
 }
 
-.tooltip.compile_fail, .tooltip.ignore {
+.tooltip.compile_fail, .tooltip.should_panic, .tooltip.ignore {
 	font-weight: bold;
 	font-size: 20px;
 }
diff --git a/src/librustdoc/html/static/themes/dark.css b/src/librustdoc/html/static/themes/dark.css
index a2986c7b927e2..41dcb5c24507c 100644
--- a/src/librustdoc/html/static/themes/dark.css
+++ b/src/librustdoc/html/static/themes/dark.css
@@ -283,6 +283,14 @@ pre.compile_fail:hover, .information:hover + pre.compile_fail {
 	border-left: 2px solid #f00;
 }
 
+pre.should_panic {
+	border-left: 2px solid rgba(255,0,0,.8);
+}
+
+pre.should_panic:hover, .information:hover + pre.should_panic {
+	border-left: 2px solid #f00;
+}
+
 pre.ignore {
 	border-left: 2px solid rgba(255,142,0,.6);
 }
@@ -299,6 +307,14 @@ pre.ignore:hover, .information:hover + pre.ignore {
 	color: #f00;
 }
 
+.tooltip.should_panic {
+	color: rgba(255,0,0,.8);
+}
+
+.information > .should_panic:hover {
+	color: #f00;
+}
+
 .tooltip.ignore {
 	color: rgba(255,142,0,.6);
 }
diff --git a/src/librustdoc/html/static/themes/light.css b/src/librustdoc/html/static/themes/light.css
index be173d8eb46d3..386fe2398e63a 100644
--- a/src/librustdoc/html/static/themes/light.css
+++ b/src/librustdoc/html/static/themes/light.css
@@ -278,6 +278,14 @@ pre.compile_fail:hover, .information:hover + pre.compile_fail {
 	border-left: 2px solid #f00;
 }
 
+pre.should_panic {
+	border-left: 2px solid rgba(255,0,0,.5);
+}
+
+pre.should_panic:hover, .information:hover + pre.should_panic {
+	border-left: 2px solid #f00;
+}
+
 pre.ignore {
 	border-left: 2px solid rgba(255,142,0,.6);
 }
@@ -294,6 +302,14 @@ pre.ignore:hover, .information:hover + pre.ignore {
 	color: #f00;
 }
 
+.tooltip.should_panic {
+	color: rgba(255,0,0,.5);
+}
+
+.information > .should_panic:hover {
+	color: #f00;
+}
+
 .tooltip.ignore {
 	color: rgba(255,142,0,.6);
 }
diff --git a/src/librustdoc/lib.rs b/src/librustdoc/lib.rs
index 82d6cda986a9a..95d113166e001 100644
--- a/src/librustdoc/lib.rs
+++ b/src/librustdoc/lib.rs
@@ -165,9 +165,8 @@ fn opts() -> Vec<RustcOptGroup> {
             o.optmulti(
                 "",
                 "passes",
-                "list of passes to also run, you might want \
-                        to pass it multiple times; a value of `list` \
-                        will print available passes",
+                "list of passes to also run, you might want to pass it multiple times; a value of \
+                        `list` will print available passes",
                 "PASSES",
             )
         }),
@@ -248,8 +247,8 @@ fn opts() -> Vec<RustcOptGroup> {
                 "e",
                 "extend-css",
                 "To add some CSS rules with a given file to generate doc with your \
-                      own theme. However, your theme might break if the rustdoc's generated HTML \
-                      changes, so be careful!",
+                        own theme. However, your theme might break if the rustdoc's generated HTML \
+                        changes, so be careful!",
                 "PATH",
             )
         }),
@@ -262,7 +261,7 @@ fn opts() -> Vec<RustcOptGroup> {
                 "",
                 "playground-url",
                 "URL to send code snippets to, may be reset by --markdown-playground-url \
-                      or `#![doc(html_playground_url=...)]`",
+                        or `#![doc(html_playground_url=...)]`",
                 "URL",
             )
         }),
@@ -276,8 +275,7 @@ fn opts() -> Vec<RustcOptGroup> {
             o.optflag(
                 "",
                 "sort-modules-by-appearance",
-                "sort modules by where they appear in the \
-                                                         program, rather than alphabetically",
+                "sort modules by where they appear in the program, rather than alphabetically",
             )
         }),
         stable("theme", |o| {
@@ -358,7 +356,7 @@ fn opts() -> Vec<RustcOptGroup> {
                 "",
                 "static-root-path",
                 "Path string to force loading static files from in output pages. \
-                      If not set, uses combinations of '../' to reach the documentation root.",
+                        If not set, uses combinations of '../' to reach the documentation root.",
                 "PATH",
             )
         }),
diff --git a/src/libstd/lib.rs b/src/libstd/lib.rs
index d6493454db591..ef699ede2a140 100644
--- a/src/libstd/lib.rs
+++ b/src/libstd/lib.rs
@@ -298,6 +298,7 @@
 #![feature(prelude_import)]
 #![feature(ptr_internals)]
 #![feature(raw)]
+#![feature(raw_ref_macros)]
 #![feature(renamed_spin_loop)]
 #![feature(rustc_attrs)]
 #![feature(rustc_private)]
diff --git a/src/libstd/time.rs b/src/libstd/time.rs
index bc3bfde6d7559..295ebcbb72939 100644
--- a/src/libstd/time.rs
+++ b/src/libstd/time.rs
@@ -60,6 +60,21 @@ pub use core::time::Duration;
 /// }
 /// ```
 ///
+/// # OS-specific behaviors
+///
+/// An `Instant` is a wrapper around system-specific types and it may behave
+/// differently depending on the underlying operating system. For example,
+/// the following snippet is fine on Linux but panics on macOS:
+///
+/// ```no_run
+/// use std::time::{Instant, Duration};
+///
+/// let now = Instant::now();
+/// let max_nanoseconds = u64::MAX / 1_000_000_000;
+/// let duration = Duration::new(max_nanoseconds, 0);
+/// println!("{:?}", now + duration);
+/// ```
+///
 /// # Underlying System calls
 /// Currently, the following system calls are being used to get the current time using `now()`:
 ///
diff --git a/src/test/codegen/cdylib-external-inline-fns.rs b/src/test/codegen/cdylib-external-inline-fns.rs
new file mode 100644
index 0000000000000..519be6b6a99a4
--- /dev/null
+++ b/src/test/codegen/cdylib-external-inline-fns.rs
@@ -0,0 +1,43 @@
+// compile-flags: -C no-prepopulate-passes
+
+#![crate_type = "cdylib"]
+
+// CHECK: define void @a()
+#[no_mangle]
+#[inline]
+pub extern "C" fn a() {}
+
+// CHECK: define void @b()
+#[export_name = "b"]
+#[inline]
+pub extern "C" fn b() {}
+
+// CHECK: define void @c()
+#[no_mangle]
+#[inline]
+extern "C" fn c() {}
+
+// CHECK: define void @d()
+#[export_name = "d"]
+#[inline]
+extern "C" fn d() {}
+
+// CHECK: define void @e()
+#[no_mangle]
+#[inline(always)]
+pub extern "C" fn e() {}
+
+// CHECK: define void @f()
+#[export_name = "f"]
+#[inline(always)]
+pub extern "C" fn f() {}
+
+// CHECK: define void @g()
+#[no_mangle]
+#[inline(always)]
+extern "C" fn g() {}
+
+// CHECK: define void @h()
+#[export_name = "h"]
+#[inline(always)]
+extern "C" fn h() {}
diff --git a/src/test/codegen/export-no-mangle.rs b/src/test/codegen/export-no-mangle.rs
index 78d41e4be0ae9..59e97601c838d 100644
--- a/src/test/codegen/export-no-mangle.rs
+++ b/src/test/codegen/export-no-mangle.rs
@@ -11,11 +11,21 @@ mod private {
     #[export_name = "BAR"]
     static BAR: u32 = 3;
 
-    // CHECK: void @foo()
+    // CHECK: void @a()
     #[no_mangle]
-    pub extern fn foo() {}
+    pub extern fn a() {}
 
-    // CHECK: void @bar()
-    #[export_name = "bar"]
-    extern fn bar() {}
+    // CHECK: void @b()
+    #[export_name = "b"]
+    extern fn b() {}
+
+    // CHECK: void @c()
+    #[export_name = "c"]
+    #[inline]
+    extern fn c() {}
+
+    // CHECK: void @d()
+    #[export_name = "d"]
+    #[inline(always)]
+    extern fn d() {}
 }
diff --git a/src/test/codegen/external-no-mangle-fns.rs b/src/test/codegen/external-no-mangle-fns.rs
index 902882144996f..41820b057f1ef 100644
--- a/src/test/codegen/external-no-mangle-fns.rs
+++ b/src/test/codegen/external-no-mangle-fns.rs
@@ -53,3 +53,23 @@ fn x() {
         core::ptr::read_volatile(&42);
     }
 }
+
+// CHECK: define void @i()
+#[no_mangle]
+#[inline]
+fn i() {}
+
+// CHECK: define void @j()
+#[no_mangle]
+#[inline]
+pub fn j() {}
+
+// CHECK: define void @k()
+#[no_mangle]
+#[inline(always)]
+fn k() {}
+
+// CHECK: define void @l()
+#[no_mangle]
+#[inline(always)]
+pub fn l() {}
diff --git a/src/test/codegen/sanitizer-no-sanitize-inlining.rs b/src/test/codegen/sanitizer-no-sanitize-inlining.rs
index d96e76618d325..48231d6f7208d 100644
--- a/src/test/codegen/sanitizer-no-sanitize-inlining.rs
+++ b/src/test/codegen/sanitizer-no-sanitize-inlining.rs
@@ -13,7 +13,7 @@
 #![feature(no_sanitize)]
 
 // ASAN-LABEL: define void @test
-// ASAN:         tail call fastcc void @random_inline
+// ASAN:         call {{.*}} @random_inline
 // ASAN:       }
 //
 // LSAN-LABEL: define void @test
diff --git a/src/test/codegen/staticlib-external-inline-fns.rs b/src/test/codegen/staticlib-external-inline-fns.rs
new file mode 100644
index 0000000000000..8876ab7376afe
--- /dev/null
+++ b/src/test/codegen/staticlib-external-inline-fns.rs
@@ -0,0 +1,43 @@
+// compile-flags: -C no-prepopulate-passes
+
+#![crate_type = "staticlib"]
+
+// CHECK: define void @a()
+#[no_mangle]
+#[inline]
+pub extern "C" fn a() {}
+
+// CHECK: define void @b()
+#[export_name = "b"]
+#[inline]
+pub extern "C" fn b() {}
+
+// CHECK: define void @c()
+#[no_mangle]
+#[inline]
+extern "C" fn c() {}
+
+// CHECK: define void @d()
+#[export_name = "d"]
+#[inline]
+extern "C" fn d() {}
+
+// CHECK: define void @e()
+#[no_mangle]
+#[inline(always)]
+pub extern "C" fn e() {}
+
+// CHECK: define void @f()
+#[export_name = "f"]
+#[inline(always)]
+pub extern "C" fn f() {}
+
+// CHECK: define void @g()
+#[no_mangle]
+#[inline(always)]
+extern "C" fn g() {}
+
+// CHECK: define void @h()
+#[export_name = "h"]
+#[inline(always)]
+extern "C" fn h() {}
diff --git a/src/test/rustdoc/codeblock-title.rs b/src/test/rustdoc/codeblock-title.rs
index 2f77929c74e37..b59b21111b009 100644
--- a/src/test/rustdoc/codeblock-title.rs
+++ b/src/test/rustdoc/codeblock-title.rs
@@ -4,6 +4,7 @@
 
 // @has foo/fn.bar.html '//*[@class="tooltip compile_fail"]/span' "This example deliberately fails to compile"
 // @has foo/fn.bar.html '//*[@class="tooltip ignore"]/span' "This example is not tested"
+// @has foo/fn.bar.html '//*[@class="tooltip should_panic"]/span' "This example panics"
 
 /// foo
 ///
@@ -15,6 +16,10 @@
 /// goo();
 /// ```
 ///
+/// ```should_panic
+/// hoo();
+/// ```
+///
 /// ```
 /// let x = 0;
 /// ```
diff --git a/src/test/ui-fulldeps/internal-lints/ty_tykind_usage.rs b/src/test/ui-fulldeps/internal-lints/ty_tykind_usage.rs
index 27fe432e96ded..973294e985f7a 100644
--- a/src/test/ui-fulldeps/internal-lints/ty_tykind_usage.rs
+++ b/src/test/ui-fulldeps/internal-lints/ty_tykind_usage.rs
@@ -37,7 +37,7 @@ fn main() {
         TyKind::Bound(..) => (), //~ ERROR usage of `ty::TyKind::<kind>`
         TyKind::Placeholder(..) => (), //~ ERROR usage of `ty::TyKind::<kind>`
         TyKind::Infer(..) => (), //~ ERROR usage of `ty::TyKind::<kind>`
-        TyKind::Error => (), //~ ERROR usage of `ty::TyKind::<kind>`
+        TyKind::Error(_) => (), //~ ERROR usage of `ty::TyKind::<kind>`
     }
 
     if let ty::Int(int_ty) = kind {}
diff --git a/src/test/ui-fulldeps/internal-lints/ty_tykind_usage.stderr b/src/test/ui-fulldeps/internal-lints/ty_tykind_usage.stderr
index 0486c90a5a07a..d6e4c85c190d5 100644
--- a/src/test/ui-fulldeps/internal-lints/ty_tykind_usage.stderr
+++ b/src/test/ui-fulldeps/internal-lints/ty_tykind_usage.stderr
@@ -169,7 +169,7 @@ LL |         TyKind::Infer(..) => (),
 error: usage of `ty::TyKind::<kind>`
   --> $DIR/ty_tykind_usage.rs:40:9
    |
-LL |         TyKind::Error => (),
+LL |         TyKind::Error(_) => (),
    |         ^^^^^^ help: try using ty::<kind> directly: `ty`
 
 error: usage of `ty::TyKind::<kind>`
diff --git a/src/test/ui/associated-types/associated-types-eq-1.stderr b/src/test/ui/associated-types/associated-types-eq-1.stderr
index 66c5f34644c01..53a45cf4e4f4d 100644
--- a/src/test/ui/associated-types/associated-types-eq-1.stderr
+++ b/src/test/ui/associated-types/associated-types-eq-1.stderr
@@ -4,7 +4,16 @@ error[E0412]: cannot find type `A` in this scope
 LL | fn foo2<I: Foo>(x: I) {
    |         - similarly named type parameter `I` defined here
 LL |     let _: A = x.boo();
-   |            ^ help: a type parameter with a similar name exists: `I`
+   |            ^
+   |
+help: a type parameter with a similar name exists
+   |
+LL |     let _: I = x.boo();
+   |            ^
+help: you might be missing a type parameter
+   |
+LL | fn foo2<I: Foo, A>(x: I) {
+   |               ^^^
 
 error: aborting due to previous error
 
diff --git a/src/test/ui/async-await/issues/issue-62097.stderr b/src/test/ui/async-await/issues/issue-62097.stderr
index af8fc2cd2ab45..0f58b158904db 100644
--- a/src/test/ui/async-await/issues/issue-62097.stderr
+++ b/src/test/ui/async-await/issues/issue-62097.stderr
@@ -1,13 +1,14 @@
-error: cannot infer an appropriate lifetime
+error[E0759]: cannot infer an appropriate lifetime
   --> $DIR/issue-62097.rs:12:31
    |
 LL |     pub async fn run_dummy_fn(&self) {
    |                               ^^^^^
    |                               |
-   |                               data with this lifetime...
+   |                               this data with an anonymous lifetime `'_`...
    |                               ...is captured here...
 LL |         foo(|| self.bar()).await;
-   |         --- ...and required to be `'static` by this
+   |         --- ...and is required to live as long as `'static` here
 
 error: aborting due to previous error
 
+For more information about this error, try `rustc --explain E0759`.
diff --git a/src/test/ui/cast/cast-from-nil.stderr b/src/test/ui/cast/cast-from-nil.stderr
index c8e3628a7ded8..dab133cfb4b67 100644
--- a/src/test/ui/cast/cast-from-nil.stderr
+++ b/src/test/ui/cast/cast-from-nil.stderr
@@ -2,9 +2,7 @@ error[E0605]: non-primitive cast: `()` as `u32`
   --> $DIR/cast-from-nil.rs:2:21
    |
 LL | fn main() { let u = (assert!(true) as u32); }
-   |                     ^^^^^^^^^^^^^^^^^^^^^^
-   |
-   = note: an `as` expression can only be used to convert between primitive types. Consider using the `From` trait
+   |                     ^^^^^^^^^^^^^^^^^^^^^^ an `as` expression can only be used to convert between primitive types or to coerce to a specific trait object
 
 error: aborting due to previous error
 
diff --git a/src/test/ui/cast/cast-to-bare-fn.stderr b/src/test/ui/cast/cast-to-bare-fn.stderr
index 84933dca929a4..d97b0c5f8aadc 100644
--- a/src/test/ui/cast/cast-to-bare-fn.stderr
+++ b/src/test/ui/cast/cast-to-bare-fn.stderr
@@ -2,17 +2,13 @@ error[E0605]: non-primitive cast: `fn(isize) {foo}` as `extern "C" fn() -> isize
   --> $DIR/cast-to-bare-fn.rs:5:13
    |
 LL |     let x = foo as extern "C" fn() -> isize;
-   |             ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
-   |
-   = note: an `as` expression can only be used to convert between primitive types. Consider using the `From` trait
+   |             ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ invalid cast
 
 error[E0605]: non-primitive cast: `u64` as `fn(isize) -> (isize, isize)`
   --> $DIR/cast-to-bare-fn.rs:7:13
    |
 LL |     let y = v as extern "Rust" fn(isize) -> (isize, isize);
-   |             ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
-   |
-   = note: an `as` expression can only be used to convert between primitive types. Consider using the `From` trait
+   |             ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ invalid cast
 
 error: aborting due to 2 previous errors
 
diff --git a/src/test/ui/cast/cast-to-nil.stderr b/src/test/ui/cast/cast-to-nil.stderr
index 478f6b69dafc8..29a9baffd71d7 100644
--- a/src/test/ui/cast/cast-to-nil.stderr
+++ b/src/test/ui/cast/cast-to-nil.stderr
@@ -2,9 +2,7 @@ error[E0605]: non-primitive cast: `u32` as `()`
   --> $DIR/cast-to-nil.rs:2:21
    |
 LL | fn main() { let u = 0u32 as (); }
-   |                     ^^^^^^^^^^
-   |
-   = note: an `as` expression can only be used to convert between primitive types. Consider using the `From` trait
+   |                     ^^^^^^^^^^ an `as` expression can only be used to convert between primitive types or to coerce to a specific trait object
 
 error: aborting due to previous error
 
diff --git a/src/test/ui/cast/cast-to-unsized-trait-object-suggestion.stderr b/src/test/ui/cast/cast-to-unsized-trait-object-suggestion.stderr
index ffa02533d8b66..9b86f8d4def86 100644
--- a/src/test/ui/cast/cast-to-unsized-trait-object-suggestion.stderr
+++ b/src/test/ui/cast/cast-to-unsized-trait-object-suggestion.stderr
@@ -12,7 +12,7 @@ error[E0620]: cast to unsized type: `std::boxed::Box<{integer}>` as `dyn std::ma
 LL |     Box::new(1) as dyn Send;
    |     ^^^^^^^^^^^^^^^--------
    |                    |
-   |                    help: try casting to a `Box` instead: `Box<dyn Send>`
+   |                    help: you can cast to a `Box` instead: `Box<dyn Send>`
 
 error: aborting due to 2 previous errors
 
diff --git a/src/test/ui/closures/closure-no-fn-3.stderr b/src/test/ui/closures/closure-no-fn-3.stderr
index ab6056b65473e..4b3b4be798fc1 100644
--- a/src/test/ui/closures/closure-no-fn-3.stderr
+++ b/src/test/ui/closures/closure-no-fn-3.stderr
@@ -2,9 +2,7 @@ error[E0605]: non-primitive cast: `[closure@$DIR/closure-no-fn-3.rs:6:27: 6:37 b
   --> $DIR/closure-no-fn-3.rs:6:27
    |
 LL |     let baz: fn() -> u8 = (|| { b }) as fn() -> u8;
-   |                           ^^^^^^^^^^^^^^^^^^^^^^^^
-   |
-   = note: an `as` expression can only be used to convert between primitive types. Consider using the `From` trait
+   |                           ^^^^^^^^^^^^^^^^^^^^^^^^ invalid cast
 
 error: aborting due to previous error
 
diff --git a/src/test/ui/coercion/coerce-to-bang-cast.stderr b/src/test/ui/coercion/coerce-to-bang-cast.stderr
index ff30ebc09c63a..d3adbd5158dbb 100644
--- a/src/test/ui/coercion/coerce-to-bang-cast.stderr
+++ b/src/test/ui/coercion/coerce-to-bang-cast.stderr
@@ -2,17 +2,13 @@ error[E0605]: non-primitive cast: `i32` as `!`
   --> $DIR/coerce-to-bang-cast.rs:6:13
    |
 LL |     let y = {return; 22} as !;
-   |             ^^^^^^^^^^^^^^^^^
-   |
-   = note: an `as` expression can only be used to convert between primitive types. Consider using the `From` trait
+   |             ^^^^^^^^^^^^^^^^^ an `as` expression can only be used to convert between primitive types or to coerce to a specific trait object
 
 error[E0605]: non-primitive cast: `i32` as `!`
   --> $DIR/coerce-to-bang-cast.rs:11:13
    |
 LL |     let y = 22 as !;
-   |             ^^^^^^^
-   |
-   = note: an `as` expression can only be used to convert between primitive types. Consider using the `From` trait
+   |             ^^^^^^^ an `as` expression can only be used to convert between primitive types or to coerce to a specific trait object
 
 error: aborting due to 2 previous errors
 
diff --git a/src/test/ui/consts/const-eval/const-eval-overflow-4b.stderr b/src/test/ui/consts/const-eval/const-eval-overflow-4b.stderr
index 5b2c4116c4b1d..e4d256c0ad192 100644
--- a/src/test/ui/consts/const-eval/const-eval-overflow-4b.stderr
+++ b/src/test/ui/consts/const-eval/const-eval-overflow-4b.stderr
@@ -16,7 +16,7 @@ error[E0604]: only `u8` can be cast as `char`, not `i8`
   --> $DIR/const-eval-overflow-4b.rs:25:13
    |
 LL |     : [u32; 5i8 as char as usize]
-   |             ^^^^^^^^^^^
+   |             ^^^^^^^^^^^ invalid cast
 
 error: aborting due to 3 previous errors
 
diff --git a/src/test/ui/error-codes/E0604.stderr b/src/test/ui/error-codes/E0604.stderr
index 5861bdcb7a953..18835310bd5e8 100644
--- a/src/test/ui/error-codes/E0604.stderr
+++ b/src/test/ui/error-codes/E0604.stderr
@@ -2,7 +2,7 @@ error[E0604]: only `u8` can be cast as `char`, not `u32`
   --> $DIR/E0604.rs:2:5
    |
 LL |     1u32 as char;
-   |     ^^^^^^^^^^^^
+   |     ^^^^^^^^^^^^ invalid cast
 
 error: aborting due to previous error
 
diff --git a/src/test/ui/error-codes/E0605.stderr b/src/test/ui/error-codes/E0605.stderr
index 95e899db8b7e9..f23d2008e0b5f 100644
--- a/src/test/ui/error-codes/E0605.stderr
+++ b/src/test/ui/error-codes/E0605.stderr
@@ -2,17 +2,13 @@ error[E0605]: non-primitive cast: `u8` as `std::vec::Vec<u8>`
   --> $DIR/E0605.rs:3:5
    |
 LL |     x as Vec<u8>;
-   |     ^^^^^^^^^^^^
-   |
-   = note: an `as` expression can only be used to convert between primitive types. Consider using the `From` trait
+   |     ^^^^^^^^^^^^ an `as` expression can only be used to convert between primitive types or to coerce to a specific trait object
 
 error[E0605]: non-primitive cast: `*const u8` as `&u8`
   --> $DIR/E0605.rs:6:5
    |
 LL |     v as &u8;
-   |     ^^^^^^^^
-   |
-   = note: an `as` expression can only be used to convert between primitive types. Consider using the `From` trait
+   |     ^^^^^^^^ an `as` expression can only be used to convert between primitive types or to coerce to a specific trait object
 
 error: aborting due to 2 previous errors
 
diff --git a/src/test/ui/error-festival.stderr b/src/test/ui/error-festival.stderr
index 7f524230ef006..905195d4ad963 100644
--- a/src/test/ui/error-festival.stderr
+++ b/src/test/ui/error-festival.stderr
@@ -42,15 +42,13 @@ error[E0604]: only `u8` can be cast as `char`, not `u32`
   --> $DIR/error-festival.rs:25:5
    |
 LL |     0u32 as char;
-   |     ^^^^^^^^^^^^
+   |     ^^^^^^^^^^^^ invalid cast
 
 error[E0605]: non-primitive cast: `u8` as `std::vec::Vec<u8>`
   --> $DIR/error-festival.rs:29:5
    |
 LL |     x as Vec<u8>;
-   |     ^^^^^^^^^^^^
-   |
-   = note: an `as` expression can only be used to convert between primitive types. Consider using the `From` trait
+   |     ^^^^^^^^^^^^ an `as` expression can only be used to convert between primitive types or to coerce to a specific trait object
 
 error[E0054]: cannot cast as `bool`
   --> $DIR/error-festival.rs:33:24
diff --git a/src/test/ui/fat-ptr-cast.stderr b/src/test/ui/fat-ptr-cast.stderr
index 93e1471838f72..56d5a26beb04e 100644
--- a/src/test/ui/fat-ptr-cast.stderr
+++ b/src/test/ui/fat-ptr-cast.stderr
@@ -34,9 +34,7 @@ error[E0605]: non-primitive cast: `std::boxed::Box<[i32]>` as `usize`
   --> $DIR/fat-ptr-cast.rs:14:5
    |
 LL |     b as usize;
-   |     ^^^^^^^^^^
-   |
-   = note: an `as` expression can only be used to convert between primitive types. Consider using the `From` trait
+   |     ^^^^^^^^^^ an `as` expression can only be used to convert between primitive types or to coerce to a specific trait object
 
 error[E0606]: casting `*const [i32]` as `usize` is invalid
   --> $DIR/fat-ptr-cast.rs:15:5
diff --git a/src/test/ui/impl-trait/binding-without-value.rs b/src/test/ui/impl-trait/binding-without-value.rs
new file mode 100644
index 0000000000000..6a97f28ff552b
--- /dev/null
+++ b/src/test/ui/impl-trait/binding-without-value.rs
@@ -0,0 +1,9 @@
+#![allow(incomplete_features)]
+#![feature(impl_trait_in_bindings)]
+
+fn foo() {
+    let _ : impl Copy;
+    //~^ ERROR cannot resolve opaque type
+}
+
+fn main() {}
diff --git a/src/test/ui/impl-trait/binding-without-value.stderr b/src/test/ui/impl-trait/binding-without-value.stderr
new file mode 100644
index 0000000000000..0d2faeaf85d10
--- /dev/null
+++ b/src/test/ui/impl-trait/binding-without-value.stderr
@@ -0,0 +1,16 @@
+error[E0720]: cannot resolve opaque type
+  --> $DIR/binding-without-value.rs:5:13
+   |
+LL |     let _ : impl Copy;
+   |         -   ^^^^^^^^^ cannot resolve opaque type
+   |         |
+   |         this binding might not have a concrete type
+   |
+help: set the binding to a value for a concrete type to be resolved
+   |
+LL |     let _ : impl Copy = /* value */;
+   |                       ^^^^^^^^^^^^^
+
+error: aborting due to previous error
+
+For more information about this error, try `rustc --explain E0720`.
diff --git a/src/test/ui/impl-trait/issues/infinite-impl-trait-issue-38064.rs b/src/test/ui/impl-trait/issues/infinite-impl-trait-issue-38064.rs
index 150a8015cbc75..451ddb3cce0e0 100644
--- a/src/test/ui/impl-trait/issues/infinite-impl-trait-issue-38064.rs
+++ b/src/test/ui/impl-trait/issues/infinite-impl-trait-issue-38064.rs
@@ -5,13 +5,13 @@
 
 trait Quux {}
 
-fn foo() -> impl Quux { //~ opaque type expands to a recursive type
+fn foo() -> impl Quux { //~ ERROR cannot resolve opaque type
     struct Foo<T>(T);
     impl<T> Quux for Foo<T> {}
     Foo(bar())
 }
 
-fn bar() -> impl Quux { //~ opaque type expands to a recursive type
+fn bar() -> impl Quux { //~ ERROR cannot resolve opaque type
     struct Bar<T>(T);
     impl<T> Quux for Bar<T> {}
     Bar(foo())
diff --git a/src/test/ui/impl-trait/issues/infinite-impl-trait-issue-38064.stderr b/src/test/ui/impl-trait/issues/infinite-impl-trait-issue-38064.stderr
index d10001e8a8e53..c538b77098a2d 100644
--- a/src/test/ui/impl-trait/issues/infinite-impl-trait-issue-38064.stderr
+++ b/src/test/ui/impl-trait/issues/infinite-impl-trait-issue-38064.stderr
@@ -1,18 +1,26 @@
-error[E0720]: opaque type expands to a recursive type
+error[E0720]: cannot resolve opaque type
   --> $DIR/infinite-impl-trait-issue-38064.rs:8:13
    |
 LL | fn foo() -> impl Quux {
-   |             ^^^^^^^^^ expands to a recursive type
-   |
-   = note: expanded type is `foo::Foo<bar::Bar<impl Quux>>`
+   |             ^^^^^^^^^ recursive opaque type
+...
+LL |     Foo(bar())
+   |     ---------- returning here with type `foo::Foo<impl Quux>`
+...
+LL | fn bar() -> impl Quux {
+   |             --------- returning this opaque type `foo::Foo<impl Quux>`
 
-error[E0720]: opaque type expands to a recursive type
+error[E0720]: cannot resolve opaque type
   --> $DIR/infinite-impl-trait-issue-38064.rs:14:13
    |
+LL | fn foo() -> impl Quux {
+   |             --------- returning this opaque type `bar::Bar<impl Quux>`
+...
 LL | fn bar() -> impl Quux {
-   |             ^^^^^^^^^ expands to a recursive type
-   |
-   = note: expanded type is `bar::Bar<foo::Foo<impl Quux>>`
+   |             ^^^^^^^^^ recursive opaque type
+...
+LL |     Bar(foo())
+   |     ---------- returning here with type `bar::Bar<impl Quux>`
 
 error: aborting due to 2 previous errors
 
diff --git a/src/test/ui/impl-trait/must_outlive_least_region_or_bound.nll.stderr b/src/test/ui/impl-trait/must_outlive_least_region_or_bound.nll.stderr
index 1806d2607a3ac..ca9ca8a9debe2 100644
--- a/src/test/ui/impl-trait/must_outlive_least_region_or_bound.nll.stderr
+++ b/src/test/ui/impl-trait/must_outlive_least_region_or_bound.nll.stderr
@@ -26,7 +26,34 @@ LL | fn explicit<'a>(x: &'a i32) -> impl Copy + 'a { x }
    |                                ^^^^^^^^^^^^^^
 
 error: lifetime may not live long enough
-  --> $DIR/must_outlive_least_region_or_bound.rs:12:69
+  --> $DIR/must_outlive_least_region_or_bound.rs:9:46
+   |
+LL | fn elided2(x: &i32) -> impl Copy + 'static { x }
+   |               -                              ^ returning this value requires that `'1` must outlive `'static`
+   |               |
+   |               let's call the lifetime of this reference `'1`
+   |
+   = help: consider replacing `'1` with `'static`
+
+error: lifetime may not live long enough
+  --> $DIR/must_outlive_least_region_or_bound.rs:12:55
+   |
+LL | fn explicit2<'a>(x: &'a i32) -> impl Copy + 'static { x }
+   |              -- lifetime `'a` defined here            ^ returning this value requires that `'a` must outlive `'static`
+   |
+   = help: consider replacing `'a` with `'static`
+   = help: consider replacing `'a` with `'static`
+
+error[E0621]: explicit lifetime required in the type of `x`
+  --> $DIR/must_outlive_least_region_or_bound.rs:15:41
+   |
+LL | fn foo<'a>(x: &i32) -> impl Copy + 'a { x }
+   |               ----                      ^ lifetime `'a` required
+   |               |
+   |               help: add explicit lifetime `'a` to the type of `x`: `&'a i32`
+
+error: lifetime may not live long enough
+  --> $DIR/must_outlive_least_region_or_bound.rs:33:69
    |
 LL | fn with_bound<'a>(x: &'a i32) -> impl LifetimeTrait<'a> + 'static { x }
    |               -- lifetime `'a` defined here                         ^ returning this value requires that `'a` must outlive `'static`
@@ -35,7 +62,7 @@ LL | fn with_bound<'a>(x: &'a i32) -> impl LifetimeTrait<'a> + 'static { x }
    = help: consider replacing `'a` with `'static`
 
 error: lifetime may not live long enough
-  --> $DIR/must_outlive_least_region_or_bound.rs:17:61
+  --> $DIR/must_outlive_least_region_or_bound.rs:38:61
    |
 LL | fn move_lifetime_into_fn<'a, 'b>(x: &'a u32, y: &'b u32) -> impl Fn(&'a u32) {
    |                          --  -- lifetime `'b` defined here  ^^^^^^^^^^^^^^^^ opaque type requires that `'b` must outlive `'a`
@@ -45,13 +72,14 @@ LL | fn move_lifetime_into_fn<'a, 'b>(x: &'a u32, y: &'b u32) -> impl Fn(&'a u32
    = help: consider adding the following bound: `'b: 'a`
 
 error[E0310]: the parameter type `T` may not live long enough
-  --> $DIR/must_outlive_least_region_or_bound.rs:22:51
+  --> $DIR/must_outlive_least_region_or_bound.rs:43:51
    |
 LL | fn ty_param_wont_outlive_static<T:Debug>(x: T) -> impl Debug + 'static {
    |                                                   ^^^^^^^^^^^^^^^^^^^^
    |
    = help: consider adding an explicit lifetime bound `T: 'static`...
 
-error: aborting due to 5 previous errors
+error: aborting due to 8 previous errors
 
-For more information about this error, try `rustc --explain E0310`.
+Some errors have detailed explanations: E0310, E0621.
+For more information about an error, try `rustc --explain E0310`.
diff --git a/src/test/ui/impl-trait/must_outlive_least_region_or_bound.rs b/src/test/ui/impl-trait/must_outlive_least_region_or_bound.rs
index 00f3490991b52..837244b022721 100644
--- a/src/test/ui/impl-trait/must_outlive_least_region_or_bound.rs
+++ b/src/test/ui/impl-trait/must_outlive_least_region_or_bound.rs
@@ -6,6 +6,27 @@ fn elided(x: &i32) -> impl Copy { x }
 fn explicit<'a>(x: &'a i32) -> impl Copy { x }
 //~^ ERROR cannot infer an appropriate lifetime
 
+fn elided2(x: &i32) -> impl Copy + 'static { x }
+//~^ ERROR cannot infer an appropriate lifetime
+
+fn explicit2<'a>(x: &'a i32) -> impl Copy + 'static { x }
+//~^ ERROR cannot infer an appropriate lifetime
+
+fn foo<'a>(x: &i32) -> impl Copy + 'a { x }
+//~^ ERROR explicit lifetime required in the type of `x`
+
+fn elided3(x: &i32) -> Box<dyn Debug> { Box::new(x) }
+//~^ ERROR cannot infer an appropriate lifetime
+
+fn explicit3<'a>(x: &'a i32) -> Box<dyn Debug> { Box::new(x) }
+//~^ ERROR cannot infer an appropriate lifetime
+
+fn elided4(x: &i32) -> Box<dyn Debug + 'static> { Box::new(x) }
+//~^ ERROR cannot infer an appropriate lifetime
+
+fn explicit4<'a>(x: &'a i32) -> Box<dyn Debug + 'static> { Box::new(x) }
+//~^ ERROR cannot infer an appropriate lifetime
+
 trait LifetimeTrait<'a> {}
 impl<'a> LifetimeTrait<'a> for &'a i32 {}
 
diff --git a/src/test/ui/impl-trait/must_outlive_least_region_or_bound.stderr b/src/test/ui/impl-trait/must_outlive_least_region_or_bound.stderr
index d7dae6a08a7b9..e1fa4f02b6fcf 100644
--- a/src/test/ui/impl-trait/must_outlive_least_region_or_bound.stderr
+++ b/src/test/ui/impl-trait/must_outlive_least_region_or_bound.stderr
@@ -1,47 +1,113 @@
-error: cannot infer an appropriate lifetime
+error[E0759]: cannot infer an appropriate lifetime
   --> $DIR/must_outlive_least_region_or_bound.rs:3:35
    |
 LL | fn elided(x: &i32) -> impl Copy { x }
-   |              ----     ---------   ^ ...and is captured here
-   |              |        |
-   |              |        ...is required to be `'static` by this...
-   |              data with this lifetime...
+   |              ----                 ^ ...is captured here...
+   |              |
+   |              this data with an anonymous lifetime `'_`...
    |
-help: to permit non-static references in an `impl Trait` value, you can add an explicit bound for the anonymous lifetime #1 defined on the function body at 3:1
+note: ...and is required to live as long as `'static` here
+  --> $DIR/must_outlive_least_region_or_bound.rs:3:23
+   |
+LL | fn elided(x: &i32) -> impl Copy { x }
+   |                       ^^^^^^^^^
+help: to declare that the `impl Trait` captures data from argument `x`, you can add an explicit `'_` lifetime bound
    |
 LL | fn elided(x: &i32) -> impl Copy + '_ { x }
    |                                 ^^^^
 
-error: cannot infer an appropriate lifetime
+error[E0759]: cannot infer an appropriate lifetime
   --> $DIR/must_outlive_least_region_or_bound.rs:6:44
    |
 LL | fn explicit<'a>(x: &'a i32) -> impl Copy { x }
-   |                    -------     ---------   ^ ...and is captured here
-   |                    |           |
-   |                    |           ...is required to be `'static` by this...
-   |                    data with this lifetime...
+   |                    -------                 ^ ...is captured here...
+   |                    |
+   |                    this data with lifetime `'a`...
    |
-help: to permit non-static references in an `impl Trait` value, you can add an explicit bound for the lifetime `'a` as defined on the function body at 6:13
+note: ...and is required to live as long as `'static` here
+  --> $DIR/must_outlive_least_region_or_bound.rs:6:32
+   |
+LL | fn explicit<'a>(x: &'a i32) -> impl Copy { x }
+   |                                ^^^^^^^^^
+help: to declare that the `impl Trait` captures data from argument `x`, you can add an explicit `'a` lifetime bound
    |
 LL | fn explicit<'a>(x: &'a i32) -> impl Copy + 'a { x }
    |                                          ^^^^
 
-error: cannot infer an appropriate lifetime
-  --> $DIR/must_outlive_least_region_or_bound.rs:12:69
+error[E0759]: cannot infer an appropriate lifetime
+  --> $DIR/must_outlive_least_region_or_bound.rs:9:46
+   |
+LL | fn elided2(x: &i32) -> impl Copy + 'static { x }
+   |               ----                           ^ ...is captured here...
+   |               |
+   |               this data with an anonymous lifetime `'_`...
+   |
+note: ...and is required to live as long as `'static` here
+  --> $DIR/must_outlive_least_region_or_bound.rs:9:24
+   |
+LL | fn elided2(x: &i32) -> impl Copy + 'static { x }
+   |                        ^^^^^^^^^^^^^^^^^^^
+help: consider changing the `impl Trait`'s explicit `'static` bound to the lifetime of argument `x`
+   |
+LL | fn elided2(x: &i32) -> impl Copy + '_ { x }
+   |                                    ^^
+help: alternatively, add an explicit `'static` bound to this reference
+   |
+LL | fn elided2(x: &'static i32) -> impl Copy + 'static { x }
+   |               ^^^^^^^^^^^^
+
+error[E0759]: cannot infer an appropriate lifetime
+  --> $DIR/must_outlive_least_region_or_bound.rs:12:55
+   |
+LL | fn explicit2<'a>(x: &'a i32) -> impl Copy + 'static { x }
+   |                     -------                           ^ ...is captured here...
+   |                     |
+   |                     this data with lifetime `'a`...
+   |
+note: ...and is required to live as long as `'static` here
+  --> $DIR/must_outlive_least_region_or_bound.rs:12:33
+   |
+LL | fn explicit2<'a>(x: &'a i32) -> impl Copy + 'static { x }
+   |                                 ^^^^^^^^^^^^^^^^^^^
+help: consider changing the `impl Trait`'s explicit `'static` bound to the lifetime of argument `x`
+   |
+LL | fn explicit2<'a>(x: &'a i32) -> impl Copy + 'a { x }
+   |                                             ^^
+help: alternatively, add an explicit `'static` bound to this reference
+   |
+LL | fn explicit2<'a>(x: &'static i32) -> impl Copy + 'static { x }
+   |                     ^^^^^^^^^^^^
+
+error[E0621]: explicit lifetime required in the type of `x`
+  --> $DIR/must_outlive_least_region_or_bound.rs:15:24
+   |
+LL | fn foo<'a>(x: &i32) -> impl Copy + 'a { x }
+   |               ----     ^^^^^^^^^^^^^^ lifetime `'a` required
+   |               |
+   |               help: add explicit lifetime `'a` to the type of `x`: `&'a i32`
+
+error[E0759]: cannot infer an appropriate lifetime
+  --> $DIR/must_outlive_least_region_or_bound.rs:33:69
    |
 LL | fn with_bound<'a>(x: &'a i32) -> impl LifetimeTrait<'a> + 'static { x }
-   |                      -------     --------------------------------   ^ ...and is captured here
-   |                      |           |
-   |                      |           ...is required to be `'static` by this...
-   |                      data with this lifetime...
+   |                      ------- this data with lifetime `'a`...        ^ ...is captured here...
    |
-help: to permit non-static references in an `impl Trait` value, you can add an explicit bound for the lifetime `'a` as defined on the function body at 12:15
+note: ...and is required to live as long as `'static` here
+  --> $DIR/must_outlive_least_region_or_bound.rs:33:34
+   |
+LL | fn with_bound<'a>(x: &'a i32) -> impl LifetimeTrait<'a> + 'static { x }
+   |                                  ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
+help: consider changing the `impl Trait`'s explicit `'static` bound to the lifetime of argument `x`
    |
-LL | fn with_bound<'a>(x: &'a i32) -> impl LifetimeTrait<'a> + 'static + 'a { x }
-   |                                                                   ^^^^
+LL | fn with_bound<'a>(x: &'a i32) -> impl LifetimeTrait<'a> + 'a { x }
+   |                                                           ^^
+help: alternatively, add an explicit `'static` bound to this reference
+   |
+LL | fn with_bound<'a>(x: &'static i32) -> impl LifetimeTrait<'a> + 'static { x }
+   |                      ^^^^^^^^^^^^
 
 error[E0623]: lifetime mismatch
-  --> $DIR/must_outlive_least_region_or_bound.rs:17:61
+  --> $DIR/must_outlive_least_region_or_bound.rs:38:61
    |
 LL | fn move_lifetime_into_fn<'a, 'b>(x: &'a u32, y: &'b u32) -> impl Fn(&'a u32) {
    |                                                 -------     ^^^^^^^^^^^^^^^^
@@ -50,14 +116,72 @@ LL | fn move_lifetime_into_fn<'a, 'b>(x: &'a u32, y: &'b u32) -> impl Fn(&'a u32
    |                                                 this parameter and the return type are declared with different lifetimes...
 
 error[E0310]: the parameter type `T` may not live long enough
-  --> $DIR/must_outlive_least_region_or_bound.rs:22:51
+  --> $DIR/must_outlive_least_region_or_bound.rs:43:51
    |
 LL | fn ty_param_wont_outlive_static<T:Debug>(x: T) -> impl Debug + 'static {
    |                                 --                ^^^^^^^^^^^^^^^^^^^^ ...so that the type `T` will meet its required lifetime bounds
    |                                 |
    |                                 help: consider adding an explicit lifetime bound...: `T: 'static +`
 
-error: aborting due to 5 previous errors
+error[E0759]: cannot infer an appropriate lifetime
+  --> $DIR/must_outlive_least_region_or_bound.rs:18:50
+   |
+LL | fn elided3(x: &i32) -> Box<dyn Debug> { Box::new(x) }
+   |               ----                               ^ ...is captured here, requiring it to live as long as `'static`
+   |               |
+   |               this data with an anonymous lifetime `'_`...
+   |
+help: to declare that the trait object captures data from argument `x`, you can add an explicit `'_` lifetime bound
+   |
+LL | fn elided3(x: &i32) -> Box<dyn Debug + '_> { Box::new(x) }
+   |                                      ^^^^
+
+error[E0759]: cannot infer an appropriate lifetime
+  --> $DIR/must_outlive_least_region_or_bound.rs:21:59
+   |
+LL | fn explicit3<'a>(x: &'a i32) -> Box<dyn Debug> { Box::new(x) }
+   |                     -------                               ^ ...is captured here, requiring it to live as long as `'static`
+   |                     |
+   |                     this data with lifetime `'a`...
+   |
+help: to declare that the trait object captures data from argument `x`, you can add an explicit `'a` lifetime bound
+   |
+LL | fn explicit3<'a>(x: &'a i32) -> Box<dyn Debug + 'a> { Box::new(x) }
+   |                                               ^^^^
+
+error[E0759]: cannot infer an appropriate lifetime
+  --> $DIR/must_outlive_least_region_or_bound.rs:24:60
+   |
+LL | fn elided4(x: &i32) -> Box<dyn Debug + 'static> { Box::new(x) }
+   |               ----                                         ^ ...is captured here, requiring it to live as long as `'static`
+   |               |
+   |               this data with an anonymous lifetime `'_`...
+   |
+help: consider changing the trait object's explicit `'static` bound to the lifetime of argument `x`
+   |
+LL | fn elided4(x: &i32) -> Box<dyn Debug + '_> { Box::new(x) }
+   |                                        ^^
+help: alternatively, add an explicit `'static` bound to this reference
+   |
+LL | fn elided4(x: &'static i32) -> Box<dyn Debug + 'static> { Box::new(x) }
+   |               ^^^^^^^^^^^^
+
+error[E0759]: cannot infer an appropriate lifetime
+  --> $DIR/must_outlive_least_region_or_bound.rs:27:69
+   |
+LL | fn explicit4<'a>(x: &'a i32) -> Box<dyn Debug + 'static> { Box::new(x) }
+   |                     ------- this data with lifetime `'a`...         ^ ...is captured here, requiring it to live as long as `'static`
+   |
+help: consider changing the trait object's explicit `'static` bound to the lifetime of argument `x`
+   |
+LL | fn explicit4<'a>(x: &'a i32) -> Box<dyn Debug + 'a> { Box::new(x) }
+   |                                                 ^^
+help: alternatively, add an explicit `'static` bound to this reference
+   |
+LL | fn explicit4<'a>(x: &'static i32) -> Box<dyn Debug + 'static> { Box::new(x) }
+   |                     ^^^^^^^^^^^^
+
+error: aborting due to 12 previous errors
 
-Some errors have detailed explanations: E0310, E0623.
+Some errors have detailed explanations: E0310, E0621, E0623, E0759.
 For more information about an error, try `rustc --explain E0310`.
diff --git a/src/test/ui/impl-trait/recursive-impl-trait-type-direct.stderr b/src/test/ui/impl-trait/recursive-impl-trait-type-direct.stderr
index 5a95e2969d1b0..5a3027ec751a9 100644
--- a/src/test/ui/impl-trait/recursive-impl-trait-type-direct.stderr
+++ b/src/test/ui/impl-trait/recursive-impl-trait-type-direct.stderr
@@ -1,10 +1,11 @@
-error[E0720]: opaque type expands to a recursive type
+error[E0720]: cannot resolve opaque type
   --> $DIR/recursive-impl-trait-type-direct.rs:5:14
    |
 LL | fn test() -> impl Sized {
-   |              ^^^^^^^^^^ expands to a recursive type
-   |
-   = note: type resolves to itself
+   |              ^^^^^^^^^^ recursive opaque type
+LL |
+LL |     test()
+   |     ------ returning here with type `impl Sized`
 
 error: aborting due to previous error
 
diff --git a/src/test/ui/impl-trait/recursive-impl-trait-type-indirect.stderr b/src/test/ui/impl-trait/recursive-impl-trait-type-indirect.stderr
index 6573b00870c5b..75ff9e078cc2c 100644
--- a/src/test/ui/impl-trait/recursive-impl-trait-type-indirect.stderr
+++ b/src/test/ui/impl-trait/recursive-impl-trait-type-indirect.stderr
@@ -1,114 +1,147 @@
-error[E0720]: opaque type expands to a recursive type
+error[E0720]: cannot resolve opaque type
   --> $DIR/recursive-impl-trait-type-indirect.rs:7:22
    |
 LL | fn option(i: i32) -> impl Sized {
-   |                      ^^^^^^^^^^ expands to a recursive type
-   |
-   = note: expanded type is `std::option::Option<(impl Sized, i32)>`
+   |                      ^^^^^^^^^^ recursive opaque type
+LL |
+LL |     if i < 0 { None } else { Some((option(i - 1), i)) }
+   |                ----          ------------------------ returning here with type `std::option::Option<(impl Sized, i32)>`
+   |                |
+   |                returning here with type `std::option::Option<(impl Sized, i32)>`
 
-error[E0720]: opaque type expands to a recursive type
+error[E0720]: cannot resolve opaque type
   --> $DIR/recursive-impl-trait-type-indirect.rs:12:15
    |
 LL | fn tuple() -> impl Sized {
-   |               ^^^^^^^^^^ expands to a recursive type
-   |
-   = note: expanded type is `(impl Sized,)`
+   |               ^^^^^^^^^^ recursive opaque type
+LL |
+LL |     (tuple(),)
+   |     ---------- returning here with type `(impl Sized,)`
 
-error[E0720]: opaque type expands to a recursive type
+error[E0720]: cannot resolve opaque type
   --> $DIR/recursive-impl-trait-type-indirect.rs:17:15
    |
 LL | fn array() -> impl Sized {
-   |               ^^^^^^^^^^ expands to a recursive type
-   |
-   = note: expanded type is `[impl Sized; 1]`
+   |               ^^^^^^^^^^ recursive opaque type
+LL |
+LL |     [array()]
+   |     --------- returning here with type `[impl Sized; 1]`
 
-error[E0720]: opaque type expands to a recursive type
+error[E0720]: cannot resolve opaque type
   --> $DIR/recursive-impl-trait-type-indirect.rs:22:13
    |
 LL | fn ptr() -> impl Sized {
-   |             ^^^^^^^^^^ expands to a recursive type
-   |
-   = note: expanded type is `*const impl Sized`
+   |             ^^^^^^^^^^ recursive opaque type
+LL |
+LL |     &ptr() as *const _
+   |     ------------------ returning here with type `*const impl Sized`
 
-error[E0720]: opaque type expands to a recursive type
+error[E0720]: cannot resolve opaque type
   --> $DIR/recursive-impl-trait-type-indirect.rs:27:16
    |
 LL | fn fn_ptr() -> impl Sized {
-   |                ^^^^^^^^^^ expands to a recursive type
-   |
-   = note: expanded type is `fn() -> impl Sized`
+   |                ^^^^^^^^^^ recursive opaque type
+LL |
+LL |     fn_ptr as fn() -> _
+   |     ------------------- returning here with type `fn() -> impl Sized`
 
-error[E0720]: opaque type expands to a recursive type
+error[E0720]: cannot resolve opaque type
   --> $DIR/recursive-impl-trait-type-indirect.rs:32:25
    |
-LL | fn closure_capture() -> impl Sized {
-   |                         ^^^^^^^^^^ expands to a recursive type
-   |
-   = note: expanded type is `[closure@$DIR/recursive-impl-trait-type-indirect.rs:35:5: 37:6 x:impl Sized]`
+LL |   fn closure_capture() -> impl Sized {
+   |                           ^^^^^^^^^^ recursive opaque type
+...
+LL | /     move || {
+LL | |         x;
+LL | |     }
+   | |_____- returning here with type `[closure@$DIR/recursive-impl-trait-type-indirect.rs:35:5: 37:6 x:impl Sized]`
 
-error[E0720]: opaque type expands to a recursive type
+error[E0720]: cannot resolve opaque type
   --> $DIR/recursive-impl-trait-type-indirect.rs:40:29
    |
-LL | fn closure_ref_capture() -> impl Sized {
-   |                             ^^^^^^^^^^ expands to a recursive type
-   |
-   = note: expanded type is `[closure@$DIR/recursive-impl-trait-type-indirect.rs:43:5: 45:6 x:impl Sized]`
+LL |   fn closure_ref_capture() -> impl Sized {
+   |                               ^^^^^^^^^^ recursive opaque type
+...
+LL | /     move || {
+LL | |         &x;
+LL | |     }
+   | |_____- returning here with type `[closure@$DIR/recursive-impl-trait-type-indirect.rs:43:5: 45:6 x:impl Sized]`
 
-error[E0720]: opaque type expands to a recursive type
+error[E0720]: cannot resolve opaque type
   --> $DIR/recursive-impl-trait-type-indirect.rs:48:21
    |
 LL | fn closure_sig() -> impl Sized {
-   |                     ^^^^^^^^^^ expands to a recursive type
-   |
-   = note: expanded type is `[closure@$DIR/recursive-impl-trait-type-indirect.rs:50:5: 50:21]`
+   |                     ^^^^^^^^^^ recursive opaque type
+LL |
+LL |     || closure_sig()
+   |     ---------------- returning here with type `[closure@$DIR/recursive-impl-trait-type-indirect.rs:50:5: 50:21]`
 
-error[E0720]: opaque type expands to a recursive type
+error[E0720]: cannot resolve opaque type
   --> $DIR/recursive-impl-trait-type-indirect.rs:53:23
    |
 LL | fn generator_sig() -> impl Sized {
-   |                       ^^^^^^^^^^ expands to a recursive type
-   |
-   = note: expanded type is `[closure@$DIR/recursive-impl-trait-type-indirect.rs:55:5: 55:23]`
+   |                       ^^^^^^^^^^ recursive opaque type
+LL |
+LL |     || generator_sig()
+   |     ------------------ returning here with type `[closure@$DIR/recursive-impl-trait-type-indirect.rs:55:5: 55:23]`
 
-error[E0720]: opaque type expands to a recursive type
+error[E0720]: cannot resolve opaque type
   --> $DIR/recursive-impl-trait-type-indirect.rs:58:27
    |
-LL | fn generator_capture() -> impl Sized {
-   |                           ^^^^^^^^^^ expands to a recursive type
-   |
-   = note: expanded type is `[generator@$DIR/recursive-impl-trait-type-indirect.rs:61:5: 64:6 x:impl Sized {()}]`
+LL |   fn generator_capture() -> impl Sized {
+   |                             ^^^^^^^^^^ recursive opaque type
+...
+LL | /     move || {
+LL | |         yield;
+LL | |         x;
+LL | |     }
+   | |_____- returning here with type `[generator@$DIR/recursive-impl-trait-type-indirect.rs:61:5: 64:6 x:impl Sized {()}]`
 
-error[E0720]: opaque type expands to a recursive type
+error[E0720]: cannot resolve opaque type
   --> $DIR/recursive-impl-trait-type-indirect.rs:67:35
    |
 LL | fn substs_change<T: 'static>() -> impl Sized {
-   |                                   ^^^^^^^^^^ expands to a recursive type
-   |
-   = note: expanded type is `(impl Sized,)`
+   |                                   ^^^^^^^^^^ recursive opaque type
+LL |
+LL |     (substs_change::<&T>(),)
+   |     ------------------------ returning here with type `(impl Sized,)`
 
-error[E0720]: opaque type expands to a recursive type
+error[E0720]: cannot resolve opaque type
   --> $DIR/recursive-impl-trait-type-indirect.rs:72:24
    |
-LL | fn generator_hold() -> impl Sized {
-   |                        ^^^^^^^^^^ expands to a recursive type
-   |
-   = note: expanded type is `[generator@$DIR/recursive-impl-trait-type-indirect.rs:74:5: 78:6 {impl Sized, ()}]`
+LL |   fn generator_hold() -> impl Sized {
+   |                          ^^^^^^^^^^ recursive opaque type
+LL |
+LL | /     move || {
+LL | |         let x = generator_hold();
+LL | |         yield;
+LL | |         x;
+LL | |     }
+   | |_____- returning here with type `[generator@$DIR/recursive-impl-trait-type-indirect.rs:74:5: 78:6 {impl Sized, ()}]`
 
-error[E0720]: opaque type expands to a recursive type
+error[E0720]: cannot resolve opaque type
   --> $DIR/recursive-impl-trait-type-indirect.rs:86:26
    |
 LL | fn mutual_recursion() -> impl Sync {
-   |                          ^^^^^^^^^ expands to a recursive type
-   |
-   = note: type resolves to itself
+   |                          ^^^^^^^^^ recursive opaque type
+LL |
+LL |     mutual_recursion_b()
+   |     -------------------- returning here with type `impl Sized`
+...
+LL | fn mutual_recursion_b() -> impl Sized {
+   |                            ---------- returning this opaque type `impl Sized`
 
-error[E0720]: opaque type expands to a recursive type
+error[E0720]: cannot resolve opaque type
   --> $DIR/recursive-impl-trait-type-indirect.rs:91:28
    |
+LL | fn mutual_recursion() -> impl Sync {
+   |                          --------- returning this opaque type `impl std::marker::Sync`
+...
 LL | fn mutual_recursion_b() -> impl Sized {
-   |                            ^^^^^^^^^^ expands to a recursive type
-   |
-   = note: type resolves to itself
+   |                            ^^^^^^^^^^ recursive opaque type
+LL |
+LL |     mutual_recursion()
+   |     ------------------ returning here with type `impl std::marker::Sync`
 
 error: aborting due to 14 previous errors
 
diff --git a/src/test/ui/impl-trait/recursive-impl-trait-type-through-non-recursive.rs b/src/test/ui/impl-trait/recursive-impl-trait-type-through-non-recursive.rs
index cfd9c0ec5b45b..818e40365394d 100644
--- a/src/test/ui/impl-trait/recursive-impl-trait-type-through-non-recursive.rs
+++ b/src/test/ui/impl-trait/recursive-impl-trait-type-through-non-recursive.rs
@@ -4,21 +4,21 @@
 
 fn id<T>(t: T) -> impl Sized { t }
 
-fn recursive_id() -> impl Sized { //~ ERROR opaque type expands to a recursive type
+fn recursive_id() -> impl Sized { //~ ERROR cannot resolve opaque type
     id(recursive_id2())
 }
 
-fn recursive_id2() -> impl Sized { //~ ERROR opaque type expands to a recursive type
+fn recursive_id2() -> impl Sized { //~ ERROR cannot resolve opaque type
     id(recursive_id())
 }
 
 fn wrap<T>(t: T) -> impl Sized { (t,) }
 
-fn recursive_wrap() -> impl Sized { //~ ERROR opaque type expands to a recursive type
+fn recursive_wrap() -> impl Sized { //~ ERROR cannot resolve opaque type
     wrap(recursive_wrap2())
 }
 
-fn recursive_wrap2() -> impl Sized { //~ ERROR opaque type expands to a recursive type
+fn recursive_wrap2() -> impl Sized { //~ ERROR cannot resolve opaque type
     wrap(recursive_wrap())
 }
 
diff --git a/src/test/ui/impl-trait/recursive-impl-trait-type-through-non-recursive.stderr b/src/test/ui/impl-trait/recursive-impl-trait-type-through-non-recursive.stderr
index 73c12f6137d24..fbc58837a8e94 100644
--- a/src/test/ui/impl-trait/recursive-impl-trait-type-through-non-recursive.stderr
+++ b/src/test/ui/impl-trait/recursive-impl-trait-type-through-non-recursive.stderr
@@ -1,34 +1,46 @@
-error[E0720]: opaque type expands to a recursive type
+error[E0720]: cannot resolve opaque type
   --> $DIR/recursive-impl-trait-type-through-non-recursive.rs:7:22
    |
+LL | fn id<T>(t: T) -> impl Sized { t }
+   |                   ---------- returning this opaque type `impl Sized`
+LL | 
 LL | fn recursive_id() -> impl Sized {
-   |                      ^^^^^^^^^^ expands to a recursive type
-   |
-   = note: type resolves to itself
+   |                      ^^^^^^^^^^ recursive opaque type
+LL |     id(recursive_id2())
+   |     ------------------- returning here with type `impl Sized`
 
-error[E0720]: opaque type expands to a recursive type
+error[E0720]: cannot resolve opaque type
   --> $DIR/recursive-impl-trait-type-through-non-recursive.rs:11:23
    |
+LL | fn id<T>(t: T) -> impl Sized { t }
+   |                   ---------- returning this opaque type `impl Sized`
+...
 LL | fn recursive_id2() -> impl Sized {
-   |                       ^^^^^^^^^^ expands to a recursive type
-   |
-   = note: type resolves to itself
+   |                       ^^^^^^^^^^ recursive opaque type
+LL |     id(recursive_id())
+   |     ------------------ returning here with type `impl Sized`
 
-error[E0720]: opaque type expands to a recursive type
+error[E0720]: cannot resolve opaque type
   --> $DIR/recursive-impl-trait-type-through-non-recursive.rs:17:24
    |
+LL | fn wrap<T>(t: T) -> impl Sized { (t,) }
+   |                     ---------- returning this opaque type `impl Sized`
+LL | 
 LL | fn recursive_wrap() -> impl Sized {
-   |                        ^^^^^^^^^^ expands to a recursive type
-   |
-   = note: expanded type is `((impl Sized,),)`
+   |                        ^^^^^^^^^^ recursive opaque type
+LL |     wrap(recursive_wrap2())
+   |     ----------------------- returning here with type `impl Sized`
 
-error[E0720]: opaque type expands to a recursive type
+error[E0720]: cannot resolve opaque type
   --> $DIR/recursive-impl-trait-type-through-non-recursive.rs:21:25
    |
+LL | fn wrap<T>(t: T) -> impl Sized { (t,) }
+   |                     ---------- returning this opaque type `impl Sized`
+...
 LL | fn recursive_wrap2() -> impl Sized {
-   |                         ^^^^^^^^^^ expands to a recursive type
-   |
-   = note: expanded type is `((impl Sized,),)`
+   |                         ^^^^^^^^^^ recursive opaque type
+LL |     wrap(recursive_wrap())
+   |     ---------------------- returning here with type `impl Sized`
 
 error: aborting due to 4 previous errors
 
diff --git a/src/test/ui/impl-trait/static-return-lifetime-infered.stderr b/src/test/ui/impl-trait/static-return-lifetime-infered.stderr
index 1c3a5979ee55b..df0db6e4fc6df 100644
--- a/src/test/ui/impl-trait/static-return-lifetime-infered.stderr
+++ b/src/test/ui/impl-trait/static-return-lifetime-infered.stderr
@@ -1,36 +1,43 @@
-error: cannot infer an appropriate lifetime
+error[E0759]: cannot infer an appropriate lifetime
   --> $DIR/static-return-lifetime-infered.rs:7:16
    |
 LL |     fn iter_values_anon(&self) -> impl Iterator<Item=u32> {
-   |                         -----     ----------------------- ...is required to be `'static` by this...
-   |                         |
-   |                         data with this lifetime...
+   |                         ----- this data with an anonymous lifetime `'_`...
 LL |         self.x.iter().map(|a| a.0)
    |         ------ ^^^^
    |         |
-   |         ...and is captured here
+   |         ...is captured here...
    |
-help: to permit non-static references in an `impl Trait` value, you can add an explicit bound for the anonymous lifetime #1 defined on the method body at 6:5
+note: ...and is required to live as long as `'static` here
+  --> $DIR/static-return-lifetime-infered.rs:6:35
+   |
+LL |     fn iter_values_anon(&self) -> impl Iterator<Item=u32> {
+   |                                   ^^^^^^^^^^^^^^^^^^^^^^^
+help: to declare that the `impl Trait` captures data from argument `self`, you can add an explicit `'_` lifetime bound
    |
 LL |     fn iter_values_anon(&self) -> impl Iterator<Item=u32> + '_ {
    |                                                           ^^^^
 
-error: cannot infer an appropriate lifetime
+error[E0759]: cannot infer an appropriate lifetime
   --> $DIR/static-return-lifetime-infered.rs:11:16
    |
 LL |     fn iter_values<'a>(&'a self) -> impl Iterator<Item=u32> {
-   |                        --------     ----------------------- ...is required to be `'static` by this...
-   |                        |
-   |                        data with this lifetime...
+   |                        -------- this data with lifetime `'a`...
 LL |         self.x.iter().map(|a| a.0)
    |         ------ ^^^^
    |         |
-   |         ...and is captured here
+   |         ...is captured here...
    |
-help: to permit non-static references in an `impl Trait` value, you can add an explicit bound for the lifetime `'a` as defined on the method body at 10:20
+note: ...and is required to live as long as `'static` here
+  --> $DIR/static-return-lifetime-infered.rs:10:37
+   |
+LL |     fn iter_values<'a>(&'a self) -> impl Iterator<Item=u32> {
+   |                                     ^^^^^^^^^^^^^^^^^^^^^^^
+help: to declare that the `impl Trait` captures data from argument `self`, you can add an explicit `'a` lifetime bound
    |
 LL |     fn iter_values<'a>(&'a self) -> impl Iterator<Item=u32> + 'a {
    |                                                             ^^^^
 
 error: aborting due to 2 previous errors
 
+For more information about this error, try `rustc --explain E0759`.
diff --git a/src/test/ui/impl-trait/where-allowed-2.rs b/src/test/ui/impl-trait/where-allowed-2.rs
index f7744ef1b3eae..462508f306ef3 100644
--- a/src/test/ui/impl-trait/where-allowed-2.rs
+++ b/src/test/ui/impl-trait/where-allowed-2.rs
@@ -3,7 +3,6 @@
 use std::fmt::Debug;
 
 // Disallowed
-fn in_adt_in_return() -> Vec<impl Debug> { panic!() }
-//~^ ERROR opaque type expands to a recursive type
+fn in_adt_in_return() -> Vec<impl Debug> { panic!() } //~ ERROR cannot resolve opaque type
 
 fn main() {}
diff --git a/src/test/ui/impl-trait/where-allowed-2.stderr b/src/test/ui/impl-trait/where-allowed-2.stderr
index 1de15014c1f8d..b8e06725cbcdd 100644
--- a/src/test/ui/impl-trait/where-allowed-2.stderr
+++ b/src/test/ui/impl-trait/where-allowed-2.stderr
@@ -1,10 +1,12 @@
-error[E0720]: opaque type expands to a recursive type
+error[E0720]: cannot resolve opaque type
   --> $DIR/where-allowed-2.rs:6:30
    |
 LL | fn in_adt_in_return() -> Vec<impl Debug> { panic!() }
-   |                              ^^^^^^^^^^ expands to a recursive type
+   |                              ^^^^^^^^^^    -------- this returned value is of `!` type
+   |                              |
+   |                              cannot resolve opaque type
    |
-   = note: type resolves to itself
+   = help: this error will resolve once the item's body returns a concrete type
 
 error: aborting due to previous error
 
diff --git a/src/test/ui/issues/issue-10991.stderr b/src/test/ui/issues/issue-10991.stderr
index f12539b47cf44..5b8a182338693 100644
--- a/src/test/ui/issues/issue-10991.stderr
+++ b/src/test/ui/issues/issue-10991.stderr
@@ -2,9 +2,7 @@ error[E0605]: non-primitive cast: `()` as `usize`
   --> $DIR/issue-10991.rs:3:14
    |
 LL |     let _t = nil as usize;
-   |              ^^^^^^^^^^^^
-   |
-   = note: an `as` expression can only be used to convert between primitive types. Consider using the `From` trait
+   |              ^^^^^^^^^^^^ an `as` expression can only be used to convert between primitive types or to coerce to a specific trait object
 
 error: aborting due to previous error
 
diff --git a/src/test/ui/issues/issue-16048.rs b/src/test/ui/issues/issue-16048.rs
index 7d24f3a40a742..eaf6acff26bf3 100644
--- a/src/test/ui/issues/issue-16048.rs
+++ b/src/test/ui/issues/issue-16048.rs
@@ -18,12 +18,12 @@ impl<'a> Test<'a> for Foo<'a> {
 }
 
 impl<'a> NoLifetime for Foo<'a> {
-    fn get<'p, T : Test<'a>>(&self) -> T {
+    fn get<'p, T: Test<'a> + From<Foo<'a>>>(&self) -> T {
     //~^ ERROR E0195
     //~| NOTE lifetimes do not match method in trait
         return *self as T;
         //~^ ERROR non-primitive cast: `Foo<'a>` as `T`
-        //~| NOTE an `as` expression can only be used to convert between primitive types.
+        //~| NOTE an `as` expression can only be used to convert between primitive types
     }
 }
 
diff --git a/src/test/ui/issues/issue-16048.stderr b/src/test/ui/issues/issue-16048.stderr
index a137bcdf1915e..73610942d7a7e 100644
--- a/src/test/ui/issues/issue-16048.stderr
+++ b/src/test/ui/issues/issue-16048.stderr
@@ -4,16 +4,16 @@ error[E0195]: lifetime parameters or bounds on method `get` do not match the tra
 LL |     fn get<'p, T : Test<'p>>(&self) -> T;
    |           ------------------ lifetimes in impl do not match this method in trait
 ...
-LL |     fn get<'p, T : Test<'a>>(&self) -> T {
-   |           ^^^^^^^^^^^^^^^^^^ lifetimes do not match method in trait
+LL |     fn get<'p, T: Test<'a> + From<Foo<'a>>>(&self) -> T {
+   |           ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ lifetimes do not match method in trait
 
 error[E0605]: non-primitive cast: `Foo<'a>` as `T`
   --> $DIR/issue-16048.rs:24:16
    |
 LL |         return *self as T;
-   |                ^^^^^^^^^^
+   |                ^^^^^^^^^^ help: consider using the `From` trait instead: `T::from(*self)`
    |
-   = note: an `as` expression can only be used to convert between primitive types. Consider using the `From` trait
+   = note: an `as` expression can only be used to convert between primitive types or to coerce to a specific trait object
 
 error: aborting due to 2 previous errors
 
diff --git a/src/test/ui/issues/issue-16922.stderr b/src/test/ui/issues/issue-16922.stderr
index 02d33aae023ff..919594fc9af4b 100644
--- a/src/test/ui/issues/issue-16922.stderr
+++ b/src/test/ui/issues/issue-16922.stderr
@@ -1,18 +1,16 @@
-error: cannot infer an appropriate lifetime
+error[E0759]: cannot infer an appropriate lifetime
   --> $DIR/issue-16922.rs:4:14
    |
 LL | fn foo<T: Any>(value: &T) -> Box<dyn Any> {
-   |                       -- data with this lifetime...
+   |                       -- this data with an anonymous lifetime `'_`...
 LL |     Box::new(value) as Box<dyn Any>
-   |     ---------^^^^^-
-   |     |        |
-   |     |        ...and is captured here
-   |     ...is required to be `'static` by this...
+   |              ^^^^^ ...is captured here, requiring it to live as long as `'static`
    |
-help: to permit non-static references in a `dyn Trait` value, you can add an explicit bound for the anonymous lifetime #1 defined on the function body at 3:1
+help: to declare that the trait object captures data from argument `value`, you can add an explicit `'_` lifetime bound
    |
 LL | fn foo<T: Any>(value: &T) -> Box<dyn Any + '_> {
    |                                          ^^^^
 
 error: aborting due to previous error
 
+For more information about this error, try `rustc --explain E0759`.
diff --git a/src/test/ui/issues/issue-17441.stderr b/src/test/ui/issues/issue-17441.stderr
index 0ab035515a051..b63a3995d255d 100644
--- a/src/test/ui/issues/issue-17441.stderr
+++ b/src/test/ui/issues/issue-17441.stderr
@@ -16,7 +16,7 @@ error[E0620]: cast to unsized type: `std::boxed::Box<usize>` as `dyn std::fmt::D
 LL |     let _bar = Box::new(1_usize) as dyn std::fmt::Debug;
    |                ^^^^^^^^^^^^^^^^^^^^^-------------------
    |                                     |
-   |                                     help: try casting to a `Box` instead: `Box<dyn std::fmt::Debug>`
+   |                                     help: you can cast to a `Box` instead: `Box<dyn std::fmt::Debug>`
 
 error[E0620]: cast to unsized type: `usize` as `dyn std::fmt::Debug`
   --> $DIR/issue-17441.rs:8:16
diff --git a/src/test/ui/issues/issue-22289.stderr b/src/test/ui/issues/issue-22289.stderr
index cc7ace30cabef..4c35deb1fbe4e 100644
--- a/src/test/ui/issues/issue-22289.stderr
+++ b/src/test/ui/issues/issue-22289.stderr
@@ -2,9 +2,12 @@ error[E0605]: non-primitive cast: `i32` as `&(dyn std::any::Any + 'static)`
   --> $DIR/issue-22289.rs:2:5
    |
 LL |     0 as &dyn std::any::Any;
-   |     ^^^^^^^^^^^^^^^^^^^^^^^
+   |     ^^^^^^^^^^^^^^^^^^^^^^^ invalid cast
    |
-   = note: an `as` expression can only be used to convert between primitive types. Consider using the `From` trait
+help: borrow the value for the cast to be valid
+   |
+LL |     &0 as &dyn std::any::Any;
+   |     ^
 
 error: aborting due to previous error
 
diff --git a/src/test/ui/issues/issue-22312.rs b/src/test/ui/issues/issue-22312.rs
index 250fec2588702..4e359b3412a71 100644
--- a/src/test/ui/issues/issue-22312.rs
+++ b/src/test/ui/issues/issue-22312.rs
@@ -1,6 +1,6 @@
 use std::ops::Index;
 
-pub trait Array2D: Index<usize> {
+pub trait Array2D: Index<usize> + Sized {
     fn rows(&self) -> usize;
     fn columns(&self) -> usize;
     fn get<'a>(&'a self, y: usize, x: usize) -> Option<&'a <Self as Index<usize>>::Output> {
diff --git a/src/test/ui/issues/issue-22312.stderr b/src/test/ui/issues/issue-22312.stderr
index fc32fd376b75a..28564b074633b 100644
--- a/src/test/ui/issues/issue-22312.stderr
+++ b/src/test/ui/issues/issue-22312.stderr
@@ -2,9 +2,12 @@ error[E0605]: non-primitive cast: `Self` as `&dyn std::ops::Index<usize, Output
   --> $DIR/issue-22312.rs:11:24
    |
 LL |         let indexer = &(*self as &dyn Index<usize, Output = <Self as Index<usize>>::Output>);
-   |                        ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
+   |                        ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ invalid cast
    |
-   = note: an `as` expression can only be used to convert between primitive types. Consider using the `From` trait
+help: borrow the value for the cast to be valid
+   |
+LL |         let indexer = &(&*self as &dyn Index<usize, Output = <Self as Index<usize>>::Output>);
+   |                         ^
 
 error: aborting due to previous error
 
diff --git a/src/test/ui/issues/issue-2995.stderr b/src/test/ui/issues/issue-2995.stderr
index c316780d5f6a5..9f5968399a37d 100644
--- a/src/test/ui/issues/issue-2995.stderr
+++ b/src/test/ui/issues/issue-2995.stderr
@@ -2,9 +2,7 @@ error[E0605]: non-primitive cast: `*const isize` as `&isize`
   --> $DIR/issue-2995.rs:2:22
    |
 LL |     let _q: &isize = p as &isize;
-   |                      ^^^^^^^^^^^
-   |
-   = note: an `as` expression can only be used to convert between primitive types. Consider using the `From` trait
+   |                      ^^^^^^^^^^^ an `as` expression can only be used to convert between primitive types or to coerce to a specific trait object
 
 error: aborting due to previous error
 
diff --git a/src/test/ui/issues/issue-45730.stderr b/src/test/ui/issues/issue-45730.stderr
index d4ddba52df14a..d00f3d91b49da 100644
--- a/src/test/ui/issues/issue-45730.stderr
+++ b/src/test/ui/issues/issue-45730.stderr
@@ -1,30 +1,24 @@
 error[E0641]: cannot cast to a pointer of an unknown kind
-  --> $DIR/issue-45730.rs:3:23
+  --> $DIR/issue-45730.rs:3:28
    |
 LL |     let x: *const _ = 0 as _;
-   |                       ^^^^^-
-   |                            |
-   |                            help: consider giving more type information
+   |                            ^ needs more type information
    |
    = note: the type information given here is insufficient to check whether the pointer cast is valid
 
 error[E0641]: cannot cast to a pointer of an unknown kind
-  --> $DIR/issue-45730.rs:5:23
+  --> $DIR/issue-45730.rs:5:28
    |
 LL |     let x: *const _ = 0 as *const _;
-   |                       ^^^^^--------
-   |                            |
-   |                            help: consider giving more type information
+   |                            ^^^^^^^^ needs more type information
    |
    = note: the type information given here is insufficient to check whether the pointer cast is valid
 
 error[E0641]: cannot cast to a pointer of an unknown kind
-  --> $DIR/issue-45730.rs:8:13
+  --> $DIR/issue-45730.rs:8:44
    |
 LL |     let x = 0 as *const i32 as *const _ as *mut _;
-   |             ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^------
-   |                                            |
-   |                                            help: consider giving more type information
+   |                                            ^^^^^^ needs more type information
    |
    = note: the type information given here is insufficient to check whether the pointer cast is valid
 
diff --git a/src/test/ui/mismatched_types/cast-rfc0401.stderr b/src/test/ui/mismatched_types/cast-rfc0401.stderr
index f94dfd100a6f4..95936de218b8f 100644
--- a/src/test/ui/mismatched_types/cast-rfc0401.stderr
+++ b/src/test/ui/mismatched_types/cast-rfc0401.stderr
@@ -24,41 +24,31 @@ error[E0605]: non-primitive cast: `*const u8` as `&u8`
   --> $DIR/cast-rfc0401.rs:29:13
    |
 LL |     let _ = v as &u8;
-   |             ^^^^^^^^
-   |
-   = note: an `as` expression can only be used to convert between primitive types. Consider using the `From` trait
+   |             ^^^^^^^^ an `as` expression can only be used to convert between primitive types or to coerce to a specific trait object
 
 error[E0605]: non-primitive cast: `*const u8` as `E`
   --> $DIR/cast-rfc0401.rs:30:13
    |
 LL |     let _ = v as E;
-   |             ^^^^^^
-   |
-   = note: an `as` expression can only be used to convert between primitive types. Consider using the `From` trait
+   |             ^^^^^^ an `as` expression can only be used to convert between primitive types or to coerce to a specific trait object
 
 error[E0605]: non-primitive cast: `*const u8` as `fn()`
   --> $DIR/cast-rfc0401.rs:31:13
    |
 LL |     let _ = v as fn();
-   |             ^^^^^^^^^
-   |
-   = note: an `as` expression can only be used to convert between primitive types. Consider using the `From` trait
+   |             ^^^^^^^^^ invalid cast
 
 error[E0605]: non-primitive cast: `*const u8` as `(u32,)`
   --> $DIR/cast-rfc0401.rs:32:13
    |
 LL |     let _ = v as (u32,);
-   |             ^^^^^^^^^^^
-   |
-   = note: an `as` expression can only be used to convert between primitive types. Consider using the `From` trait
+   |             ^^^^^^^^^^^ an `as` expression can only be used to convert between primitive types or to coerce to a specific trait object
 
 error[E0605]: non-primitive cast: `std::option::Option<&*const u8>` as `*const u8`
   --> $DIR/cast-rfc0401.rs:33:13
    |
 LL |     let _ = Some(&v) as *const u8;
-   |             ^^^^^^^^^^^^^^^^^^^^^
-   |
-   = note: an `as` expression can only be used to convert between primitive types. Consider using the `From` trait
+   |             ^^^^^^^^^^^^^^^^^^^^^ an `as` expression can only be used to convert between primitive types or to coerce to a specific trait object
 
 error[E0606]: casting `*const u8` as `f32` is invalid
   --> $DIR/cast-rfc0401.rs:35:13
@@ -102,7 +92,7 @@ error[E0604]: only `u8` can be cast as `char`, not `u32`
   --> $DIR/cast-rfc0401.rs:41:13
    |
 LL |     let _ = 0x61u32 as char;
-   |             ^^^^^^^^^^^^^^^
+   |             ^^^^^^^^^^^^^^^ invalid cast
 
 error[E0606]: casting `bool` as `f32` is invalid
   --> $DIR/cast-rfc0401.rs:43:13
diff --git a/src/test/ui/mismatched_types/issue-26480.stderr b/src/test/ui/mismatched_types/issue-26480.stderr
index 69a9d03e474ba..d39b0a3207763 100644
--- a/src/test/ui/mismatched_types/issue-26480.stderr
+++ b/src/test/ui/mismatched_types/issue-26480.stderr
@@ -17,12 +17,11 @@ error[E0605]: non-primitive cast: `{integer}` as `()`
   --> $DIR/issue-26480.rs:22:19
    |
 LL |     ($x:expr) => ($x as ())
-   |                   ^^^^^^^^
+   |                   ^^^^^^^^ an `as` expression can only be used to convert between primitive types or to coerce to a specific trait object
 ...
 LL |     cast!(2);
    |     --------- in this macro invocation
    |
-   = note: an `as` expression can only be used to convert between primitive types. Consider using the `From` trait
    = note: this error originates in a macro (in Nightly builds, run with -Z macro-backtrace for more info)
 
 error: aborting due to 2 previous errors
diff --git a/src/test/ui/nonscalar-cast.fixed b/src/test/ui/nonscalar-cast.fixed
new file mode 100644
index 0000000000000..0a4b98469b2b6
--- /dev/null
+++ b/src/test/ui/nonscalar-cast.fixed
@@ -0,0 +1,16 @@
+// run-rustfix
+
+#[derive(Debug)]
+struct Foo {
+    x: isize
+}
+
+impl From<Foo> for isize {
+    fn from(val: Foo) -> isize {
+        val.x
+    }
+}
+
+fn main() {
+    println!("{}", isize::from(Foo { x: 1 })); //~ non-primitive cast: `Foo` as `isize` [E0605]
+}
diff --git a/src/test/ui/nonscalar-cast.rs b/src/test/ui/nonscalar-cast.rs
index 7e6f1fd038fb7..59fcf09666b24 100644
--- a/src/test/ui/nonscalar-cast.rs
+++ b/src/test/ui/nonscalar-cast.rs
@@ -1,8 +1,16 @@
+// run-rustfix
+
 #[derive(Debug)]
 struct Foo {
     x: isize
 }
 
+impl From<Foo> for isize {
+    fn from(val: Foo) -> isize {
+        val.x
+    }
+}
+
 fn main() {
     println!("{}", Foo { x: 1 } as isize); //~ non-primitive cast: `Foo` as `isize` [E0605]
 }
diff --git a/src/test/ui/nonscalar-cast.stderr b/src/test/ui/nonscalar-cast.stderr
index 9338688b037ff..2a7037121876d 100644
--- a/src/test/ui/nonscalar-cast.stderr
+++ b/src/test/ui/nonscalar-cast.stderr
@@ -1,10 +1,10 @@
 error[E0605]: non-primitive cast: `Foo` as `isize`
-  --> $DIR/nonscalar-cast.rs:7:20
+  --> $DIR/nonscalar-cast.rs:15:20
    |
 LL |     println!("{}", Foo { x: 1 } as isize);
-   |                    ^^^^^^^^^^^^^^^^^^^^^
+   |                    ^^^^^^^^^^^^^^^^^^^^^ help: consider using the `From` trait instead: `isize::from(Foo { x: 1 })`
    |
-   = note: an `as` expression can only be used to convert between primitive types. Consider using the `From` trait
+   = note: an `as` expression can only be used to convert between primitive types or to coerce to a specific trait object
 
 error: aborting due to previous error
 
diff --git a/src/test/ui/object-lifetime/object-lifetime-default-from-box-error.stderr b/src/test/ui/object-lifetime/object-lifetime-default-from-box-error.stderr
index 70a9bf22b8db3..1b1e0d9610724 100644
--- a/src/test/ui/object-lifetime/object-lifetime-default-from-box-error.stderr
+++ b/src/test/ui/object-lifetime/object-lifetime-default-from-box-error.stderr
@@ -1,13 +1,13 @@
-error: cannot infer an appropriate lifetime
+error[E0759]: cannot infer an appropriate lifetime
   --> $DIR/object-lifetime-default-from-box-error.rs:18:5
    |
 LL | fn load(ss: &mut SomeStruct) -> Box<dyn SomeTrait> {
-   |             --------------- data with this lifetime...
+   |             --------------- this data with an anonymous lifetime `'_`...
 ...
 LL |     ss.r
-   |     ^^^^ ...is captured and required to be `'static` here
+   |     ^^^^ ...is captured and required to live as long as `'static` here
    |
-help: to permit non-static references in a `dyn Trait` value, you can add an explicit bound for the anonymous lifetime #2 defined on the function body at 14:1
+help: to declare that the trait object captures data from argument `ss`, you can add an explicit `'_` lifetime bound
    |
 LL | fn load(ss: &mut SomeStruct) -> Box<dyn SomeTrait + '_> {
    |                                                   ^^^^
@@ -23,4 +23,5 @@ LL |     ss.r = b;
 
 error: aborting due to 2 previous errors
 
-For more information about this error, try `rustc --explain E0621`.
+Some errors have detailed explanations: E0621, E0759.
+For more information about an error, try `rustc --explain E0621`.
diff --git a/src/test/ui/order-dependent-cast-inference.stderr b/src/test/ui/order-dependent-cast-inference.stderr
index ad50b415869dd..9f4ac0fea36ef 100644
--- a/src/test/ui/order-dependent-cast-inference.stderr
+++ b/src/test/ui/order-dependent-cast-inference.stderr
@@ -1,10 +1,8 @@
 error[E0641]: cannot cast to a pointer of an unknown kind
-  --> $DIR/order-dependent-cast-inference.rs:5:17
+  --> $DIR/order-dependent-cast-inference.rs:5:22
    |
 LL |     let mut y = 0 as *const _;
-   |                 ^^^^^--------
-   |                      |
-   |                      help: consider giving more type information
+   |                      ^^^^^^^^ needs more type information
    |
    = note: the type information given here is insufficient to check whether the pointer cast is valid
 
diff --git a/src/test/ui/parser/let-binop.rs b/src/test/ui/parser/let-binop.rs
new file mode 100644
index 0000000000000..7f58f5df2d412
--- /dev/null
+++ b/src/test/ui/parser/let-binop.rs
@@ -0,0 +1,8 @@
+fn main() {
+    let a: i8 *= 1; //~ ERROR can't reassign to an uninitialized variable
+    let _ = a;
+    let b += 1; //~ ERROR can't reassign to an uninitialized variable
+    let _ = b;
+    let c *= 1; //~ ERROR can't reassign to an uninitialized variable
+    let _ = c;
+}
diff --git a/src/test/ui/parser/let-binop.stderr b/src/test/ui/parser/let-binop.stderr
new file mode 100644
index 0000000000000..71431499ac70b
--- /dev/null
+++ b/src/test/ui/parser/let-binop.stderr
@@ -0,0 +1,20 @@
+error: can't reassign to an uninitialized variable
+  --> $DIR/let-binop.rs:2:15
+   |
+LL |     let a: i8 *= 1;
+   |               ^^ help: initialize the variable
+
+error: can't reassign to an uninitialized variable
+  --> $DIR/let-binop.rs:4:11
+   |
+LL |     let b += 1;
+   |           ^^ help: initialize the variable
+
+error: can't reassign to an uninitialized variable
+  --> $DIR/let-binop.rs:6:11
+   |
+LL |     let c *= 1;
+   |           ^^ help: initialize the variable
+
+error: aborting due to 3 previous errors
+
diff --git a/src/test/ui/regions/region-object-lifetime-in-coercion.nll.stderr b/src/test/ui/regions/region-object-lifetime-in-coercion.nll.stderr
index bf02ba8eb9199..7e8f78067e08a 100644
--- a/src/test/ui/regions/region-object-lifetime-in-coercion.nll.stderr
+++ b/src/test/ui/regions/region-object-lifetime-in-coercion.nll.stderr
@@ -1,21 +1,21 @@
-error[E0621]: explicit lifetime required in the type of `v`
+error: lifetime may not live long enough
   --> $DIR/region-object-lifetime-in-coercion.rs:8:12
    |
 LL | fn a(v: &[u8]) -> Box<dyn Foo + 'static> {
-   |         ----- help: add explicit lifetime `'static` to the type of `v`: `&'static [u8]`
+   |         - let's call the lifetime of this reference `'1`
 LL |     let x: Box<dyn Foo + 'static> = Box::new(v);
-   |            ^^^^^^^^^^^^^^^^^^^^^^ lifetime `'static` required
+   |            ^^^^^^^^^^^^^^^^^^^^^^ type annotation requires that `'1` must outlive `'static`
 
-error[E0621]: explicit lifetime required in the type of `v`
-  --> $DIR/region-object-lifetime-in-coercion.rs:14:5
+error: lifetime may not live long enough
+  --> $DIR/region-object-lifetime-in-coercion.rs:13:5
    |
 LL | fn b(v: &[u8]) -> Box<dyn Foo + 'static> {
-   |         ----- help: add explicit lifetime `'static` to the type of `v`: `&'static [u8]`
+   |         - let's call the lifetime of this reference `'1`
 LL |     Box::new(v)
-   |     ^^^^^^^^^^^ lifetime `'static` required
+   |     ^^^^^^^^^^^ returning this value requires that `'1` must outlive `'static`
 
 error: lifetime may not live long enough
-  --> $DIR/region-object-lifetime-in-coercion.rs:20:5
+  --> $DIR/region-object-lifetime-in-coercion.rs:19:5
    |
 LL | fn c(v: &[u8]) -> Box<dyn Foo> {
    |         - let's call the lifetime of this reference `'1`
@@ -24,7 +24,7 @@ LL |     Box::new(v)
    |     ^^^^^^^^^^^ returning this value requires that `'1` must outlive `'static`
 
 error: lifetime may not live long enough
-  --> $DIR/region-object-lifetime-in-coercion.rs:24:5
+  --> $DIR/region-object-lifetime-in-coercion.rs:23:5
    |
 LL | fn d<'a,'b>(v: &'a [u8]) -> Box<dyn Foo+'b> {
    |      -- -- lifetime `'b` defined here
@@ -37,4 +37,3 @@ LL |     Box::new(v)
 
 error: aborting due to 4 previous errors
 
-For more information about this error, try `rustc --explain E0621`.
diff --git a/src/test/ui/regions/region-object-lifetime-in-coercion.rs b/src/test/ui/regions/region-object-lifetime-in-coercion.rs
index d56eaf77b6646..5d199149c39b8 100644
--- a/src/test/ui/regions/region-object-lifetime-in-coercion.rs
+++ b/src/test/ui/regions/region-object-lifetime-in-coercion.rs
@@ -5,13 +5,12 @@ trait Foo {}
 impl<'a> Foo for &'a [u8] {}
 
 fn a(v: &[u8]) -> Box<dyn Foo + 'static> {
-    let x: Box<dyn Foo + 'static> = Box::new(v);
-    //~^ ERROR explicit lifetime required in the type of `v` [E0621]
+    let x: Box<dyn Foo + 'static> = Box::new(v); //~ ERROR cannot infer an appropriate lifetime
     x
 }
 
 fn b(v: &[u8]) -> Box<dyn Foo + 'static> {
-    Box::new(v) //~ ERROR explicit lifetime required in the type of `v` [E0621]
+    Box::new(v) //~ ERROR cannot infer an appropriate lifetime
 }
 
 fn c(v: &[u8]) -> Box<dyn Foo> {
diff --git a/src/test/ui/regions/region-object-lifetime-in-coercion.stderr b/src/test/ui/regions/region-object-lifetime-in-coercion.stderr
index 1462af44cb15a..7f5a3a47976c7 100644
--- a/src/test/ui/regions/region-object-lifetime-in-coercion.stderr
+++ b/src/test/ui/regions/region-object-lifetime-in-coercion.stderr
@@ -1,61 +1,76 @@
-error[E0621]: explicit lifetime required in the type of `v`
-  --> $DIR/region-object-lifetime-in-coercion.rs:8:37
+error[E0759]: cannot infer an appropriate lifetime
+  --> $DIR/region-object-lifetime-in-coercion.rs:8:46
    |
 LL | fn a(v: &[u8]) -> Box<dyn Foo + 'static> {
-   |         ----- help: add explicit lifetime `'static` to the type of `v`: `&'static [u8]`
+   |         ----- this data with an anonymous lifetime `'_`...
 LL |     let x: Box<dyn Foo + 'static> = Box::new(v);
-   |                                     ^^^^^^^^^^^ lifetime `'static` required
+   |                                              ^ ...is captured here, requiring it to live as long as `'static`
+   |
+help: consider changing the trait object's explicit `'static` bound to the lifetime of argument `v`
+   |
+LL | fn a(v: &[u8]) -> Box<dyn Foo + '_> {
+   |                                 ^^
+help: alternatively, add an explicit `'static` bound to this reference
+   |
+LL | fn a(v: &'static [u8]) -> Box<dyn Foo + 'static> {
+   |         ^^^^^^^^^^^^^
 
-error[E0621]: explicit lifetime required in the type of `v`
-  --> $DIR/region-object-lifetime-in-coercion.rs:14:5
+error[E0759]: cannot infer an appropriate lifetime
+  --> $DIR/region-object-lifetime-in-coercion.rs:13:14
    |
 LL | fn b(v: &[u8]) -> Box<dyn Foo + 'static> {
-   |         ----- help: add explicit lifetime `'static` to the type of `v`: `&'static [u8]`
+   |         ----- this data with an anonymous lifetime `'_`...
 LL |     Box::new(v)
-   |     ^^^^^^^^^^^ lifetime `'static` required
+   |              ^ ...is captured here, requiring it to live as long as `'static`
+   |
+help: consider changing the trait object's explicit `'static` bound to the lifetime of argument `v`
+   |
+LL | fn b(v: &[u8]) -> Box<dyn Foo + '_> {
+   |                                 ^^
+help: alternatively, add an explicit `'static` bound to this reference
+   |
+LL | fn b(v: &'static [u8]) -> Box<dyn Foo + 'static> {
+   |         ^^^^^^^^^^^^^
 
-error: cannot infer an appropriate lifetime
-  --> $DIR/region-object-lifetime-in-coercion.rs:20:14
+error[E0759]: cannot infer an appropriate lifetime
+  --> $DIR/region-object-lifetime-in-coercion.rs:19:14
    |
 LL | fn c(v: &[u8]) -> Box<dyn Foo> {
-   |         ----- data with this lifetime...
+   |         ----- this data with an anonymous lifetime `'_`...
 ...
 LL |     Box::new(v)
-   |     ---------^-
-   |     |        |
-   |     |        ...and is captured here
-   |     ...is required to be `'static` by this...
+   |              ^ ...is captured here, requiring it to live as long as `'static`
    |
-help: to permit non-static references in a `dyn Trait` value, you can add an explicit bound for the anonymous lifetime #1 defined on the function body at 17:1
+help: to declare that the trait object captures data from argument `v`, you can add an explicit `'_` lifetime bound
    |
 LL | fn c(v: &[u8]) -> Box<dyn Foo + '_> {
    |                               ^^^^
 
 error[E0495]: cannot infer an appropriate lifetime due to conflicting requirements
-  --> $DIR/region-object-lifetime-in-coercion.rs:24:14
+  --> $DIR/region-object-lifetime-in-coercion.rs:23:14
    |
 LL |     Box::new(v)
    |              ^
    |
-note: first, the lifetime cannot outlive the lifetime `'a` as defined on the function body at 23:6...
-  --> $DIR/region-object-lifetime-in-coercion.rs:23:6
+note: first, the lifetime cannot outlive the lifetime `'a` as defined on the function body at 22:6...
+  --> $DIR/region-object-lifetime-in-coercion.rs:22:6
    |
 LL | fn d<'a,'b>(v: &'a [u8]) -> Box<dyn Foo+'b> {
    |      ^^
 note: ...so that the expression is assignable
-  --> $DIR/region-object-lifetime-in-coercion.rs:24:14
+  --> $DIR/region-object-lifetime-in-coercion.rs:23:14
    |
 LL |     Box::new(v)
    |              ^
    = note: expected `&[u8]`
               found `&'a [u8]`
-note: but, the lifetime must be valid for the lifetime `'b` as defined on the function body at 23:9...
-  --> $DIR/region-object-lifetime-in-coercion.rs:23:9
+note: but, the lifetime must be valid for the lifetime `'b` as defined on the function body at 22:9...
+  --> $DIR/region-object-lifetime-in-coercion.rs:22:9
    |
 LL | fn d<'a,'b>(v: &'a [u8]) -> Box<dyn Foo+'b> {
    |         ^^
 note: ...so that the expression is assignable
-  --> $DIR/region-object-lifetime-in-coercion.rs:24:5
+  --> $DIR/region-object-lifetime-in-coercion.rs:23:5
    |
 LL |     Box::new(v)
    |     ^^^^^^^^^^^
@@ -64,5 +79,5 @@ LL |     Box::new(v)
 
 error: aborting due to 4 previous errors
 
-Some errors have detailed explanations: E0495, E0621.
+Some errors have detailed explanations: E0495, E0759.
 For more information about an error, try `rustc --explain E0495`.
diff --git a/src/test/ui/regions/regions-close-object-into-object-2.stderr b/src/test/ui/regions/regions-close-object-into-object-2.stderr
index 147f7f3541816..114e4052aae09 100644
--- a/src/test/ui/regions/regions-close-object-into-object-2.stderr
+++ b/src/test/ui/regions/regions-close-object-into-object-2.stderr
@@ -1,28 +1,20 @@
-error[E0495]: cannot infer an appropriate lifetime for borrow expression due to conflicting requirements
+error[E0759]: cannot infer an appropriate lifetime
   --> $DIR/regions-close-object-into-object-2.rs:10:11
    |
+LL | fn g<'a, T: 'static>(v: Box<dyn A<T> + 'a>) -> Box<dyn X + 'static> {
+   |                         ------------------ this data with lifetime `'a`...
 LL |     box B(&*v) as Box<dyn X>
-   |           ^^^
-   |
-note: first, the lifetime cannot outlive the lifetime `'a` as defined on the function body at 9:6...
-  --> $DIR/regions-close-object-into-object-2.rs:9:6
+   |           ^^^ ...is captured here, requiring it to live as long as `'static`
    |
-LL | fn g<'a, T: 'static>(v: Box<dyn A<T> + 'a>) -> Box<dyn X + 'static> {
-   |      ^^
-note: ...so that the type `(dyn A<T> + 'a)` is not borrowed for too long
-  --> $DIR/regions-close-object-into-object-2.rs:10:11
+help: consider changing the trait object's explicit `'static` bound to the lifetime of argument `v`
    |
-LL |     box B(&*v) as Box<dyn X>
-   |           ^^^
-   = note: but, the lifetime must be valid for the static lifetime...
-note: ...so that the expression is assignable
-  --> $DIR/regions-close-object-into-object-2.rs:10:5
+LL | fn g<'a, T: 'static>(v: Box<dyn A<T> + 'a>) -> Box<dyn X + 'a> {
+   |                                                            ^^
+help: alternatively, add an explicit `'static` bound to this reference
    |
-LL |     box B(&*v) as Box<dyn X>
-   |     ^^^^^^^^^^^^^^^^^^^^^^^^
-   = note: expected `std::boxed::Box<(dyn X + 'static)>`
-              found `std::boxed::Box<dyn X>`
+LL | fn g<'a, T: 'static>(v: std::boxed::Box<(dyn A<T> + 'static)>) -> Box<dyn X + 'static> {
+   |                         ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
 
 error: aborting due to previous error
 
-For more information about this error, try `rustc --explain E0495`.
+For more information about this error, try `rustc --explain E0759`.
diff --git a/src/test/ui/regions/regions-close-object-into-object-4.stderr b/src/test/ui/regions/regions-close-object-into-object-4.stderr
index 6e7d6152cd09a..850d81940791f 100644
--- a/src/test/ui/regions/regions-close-object-into-object-4.stderr
+++ b/src/test/ui/regions/regions-close-object-into-object-4.stderr
@@ -1,28 +1,20 @@
-error[E0495]: cannot infer an appropriate lifetime for borrow expression due to conflicting requirements
+error[E0759]: cannot infer an appropriate lifetime
   --> $DIR/regions-close-object-into-object-4.rs:10:11
    |
+LL | fn i<'a, T, U>(v: Box<dyn A<U>+'a>) -> Box<dyn X + 'static> {
+   |                   ---------------- this data with lifetime `'a`...
 LL |     box B(&*v) as Box<dyn X>
-   |           ^^^
-   |
-note: first, the lifetime cannot outlive the lifetime `'a` as defined on the function body at 9:6...
-  --> $DIR/regions-close-object-into-object-4.rs:9:6
+   |           ^^^ ...is captured here, requiring it to live as long as `'static`
    |
-LL | fn i<'a, T, U>(v: Box<dyn A<U>+'a>) -> Box<dyn X + 'static> {
-   |      ^^
-note: ...so that the type `(dyn A<U> + 'a)` is not borrowed for too long
-  --> $DIR/regions-close-object-into-object-4.rs:10:11
+help: consider changing the trait object's explicit `'static` bound to the lifetime of argument `v`
    |
-LL |     box B(&*v) as Box<dyn X>
-   |           ^^^
-   = note: but, the lifetime must be valid for the static lifetime...
-note: ...so that the expression is assignable
-  --> $DIR/regions-close-object-into-object-4.rs:10:5
+LL | fn i<'a, T, U>(v: Box<dyn A<U>+'a>) -> Box<dyn X + 'a> {
+   |                                                    ^^
+help: alternatively, add an explicit `'static` bound to this reference
    |
-LL |     box B(&*v) as Box<dyn X>
-   |     ^^^^^^^^^^^^^^^^^^^^^^^^
-   = note: expected `std::boxed::Box<(dyn X + 'static)>`
-              found `std::boxed::Box<dyn X>`
+LL | fn i<'a, T, U>(v: std::boxed::Box<(dyn A<U> + 'static)>) -> Box<dyn X + 'static> {
+   |                   ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
 
 error: aborting due to previous error
 
-For more information about this error, try `rustc --explain E0495`.
+For more information about this error, try `rustc --explain E0759`.
diff --git a/src/test/ui/regions/regions-proc-bound-capture.nll.stderr b/src/test/ui/regions/regions-proc-bound-capture.nll.stderr
new file mode 100644
index 0000000000000..75890b8581537
--- /dev/null
+++ b/src/test/ui/regions/regions-proc-bound-capture.nll.stderr
@@ -0,0 +1,11 @@
+error: lifetime may not live long enough
+  --> $DIR/regions-proc-bound-capture.rs:9:5
+   |
+LL | fn static_proc(x: &isize) -> Box<dyn FnMut() -> (isize) + 'static> {
+   |                   - let's call the lifetime of this reference `'1`
+LL |     // This is illegal, because the region bound on `proc` is 'static.
+LL |     Box::new(move || { *x })
+   |     ^^^^^^^^^^^^^^^^^^^^^^^^ returning this value requires that `'1` must outlive `'static`
+
+error: aborting due to previous error
+
diff --git a/src/test/ui/regions/regions-proc-bound-capture.rs b/src/test/ui/regions/regions-proc-bound-capture.rs
index 0c903b7384992..8617c0e9da8f7 100644
--- a/src/test/ui/regions/regions-proc-bound-capture.rs
+++ b/src/test/ui/regions/regions-proc-bound-capture.rs
@@ -4,9 +4,9 @@ fn borrowed_proc<'a>(x: &'a isize) -> Box<dyn FnMut()->(isize) + 'a> {
     Box::new(move|| { *x })
 }
 
-fn static_proc(x: &isize) -> Box<dyn FnMut()->(isize) + 'static> {
+fn static_proc(x: &isize) -> Box<dyn FnMut() -> (isize) + 'static> {
     // This is illegal, because the region bound on `proc` is 'static.
-    Box::new(move|| { *x }) //~ ERROR explicit lifetime required in the type of `x` [E0621]
+    Box::new(move || { *x }) //~ ERROR cannot infer an appropriate lifetime
 }
 
 fn main() { }
diff --git a/src/test/ui/regions/regions-proc-bound-capture.stderr b/src/test/ui/regions/regions-proc-bound-capture.stderr
index c53af34456ef3..67eee3bb6e281 100644
--- a/src/test/ui/regions/regions-proc-bound-capture.stderr
+++ b/src/test/ui/regions/regions-proc-bound-capture.stderr
@@ -1,12 +1,21 @@
-error[E0621]: explicit lifetime required in the type of `x`
-  --> $DIR/regions-proc-bound-capture.rs:9:5
+error[E0759]: cannot infer an appropriate lifetime
+  --> $DIR/regions-proc-bound-capture.rs:9:14
    |
-LL | fn static_proc(x: &isize) -> Box<dyn FnMut()->(isize) + 'static> {
-   |                   ------ help: add explicit lifetime `'static` to the type of `x`: `&'static isize`
+LL | fn static_proc(x: &isize) -> Box<dyn FnMut() -> (isize) + 'static> {
+   |                   ------ this data with an anonymous lifetime `'_`...
 LL |     // This is illegal, because the region bound on `proc` is 'static.
-LL |     Box::new(move|| { *x })
-   |     ^^^^^^^^^^^^^^^^^^^^^^^ lifetime `'static` required
+LL |     Box::new(move || { *x })
+   |              ^^^^^^^^^^^^^^ ...is captured here, requiring it to live as long as `'static`
+   |
+help: consider changing the trait object's explicit `'static` bound to the lifetime of argument `x`
+   |
+LL | fn static_proc(x: &isize) -> Box<dyn FnMut() -> (isize) + '_> {
+   |                                                           ^^
+help: alternatively, add an explicit `'static` bound to this reference
+   |
+LL | fn static_proc(x: &'static isize) -> Box<dyn FnMut() -> (isize) + 'static> {
+   |                   ^^^^^^^^^^^^^^
 
 error: aborting due to previous error
 
-For more information about this error, try `rustc --explain E0621`.
+For more information about this error, try `rustc --explain E0759`.
diff --git a/src/test/ui/self/arbitrary_self_types_pin_lifetime_impl_trait-async.stderr b/src/test/ui/self/arbitrary_self_types_pin_lifetime_impl_trait-async.stderr
index 1aeabce5e8aaf..88bd990b1e81b 100644
--- a/src/test/ui/self/arbitrary_self_types_pin_lifetime_impl_trait-async.stderr
+++ b/src/test/ui/self/arbitrary_self_types_pin_lifetime_impl_trait-async.stderr
@@ -1,11 +1,12 @@
-error: cannot infer an appropriate lifetime
+error[E0759]: cannot infer an appropriate lifetime
   --> $DIR/arbitrary_self_types_pin_lifetime_impl_trait-async.rs:8:16
    |
 LL |     async fn f(self: Pin<&Self>) -> impl Clone { self }
-   |                ^^^^  ----------     ---------- ...and required to be `'static` by this
+   |                ^^^^  ----------     ---------- ...and is required to live as long as `'static` here
    |                |     |
-   |                |     data with this lifetime...
+   |                |     this data with an anonymous lifetime `'_`...
    |                ...is captured here...
 
 error: aborting due to previous error
 
+For more information about this error, try `rustc --explain E0759`.
diff --git a/src/test/ui/self/arbitrary_self_types_pin_lifetime_impl_trait.stderr b/src/test/ui/self/arbitrary_self_types_pin_lifetime_impl_trait.stderr
index 04c475be787b8..2e10ab3d3f9b8 100644
--- a/src/test/ui/self/arbitrary_self_types_pin_lifetime_impl_trait.stderr
+++ b/src/test/ui/self/arbitrary_self_types_pin_lifetime_impl_trait.stderr
@@ -1,16 +1,21 @@
-error: cannot infer an appropriate lifetime
+error[E0759]: cannot infer an appropriate lifetime
   --> $DIR/arbitrary_self_types_pin_lifetime_impl_trait.rs:6:44
    |
 LL |     fn f(self: Pin<&Self>) -> impl Clone { self }
-   |                ----------     ----------   ^^^^ ...and is captured here
-   |                |              |
-   |                |              ...is required to be `'static` by this...
-   |                data with this lifetime...
+   |                ----------                  ^^^^ ...is captured here...
+   |                |
+   |                this data with an anonymous lifetime `'_`...
    |
-help: to permit non-static references in an `impl Trait` value, you can add an explicit bound for the anonymous lifetime #1 defined on the method body at 6:5
+note: ...and is required to live as long as `'static` here
+  --> $DIR/arbitrary_self_types_pin_lifetime_impl_trait.rs:6:31
+   |
+LL |     fn f(self: Pin<&Self>) -> impl Clone { self }
+   |                               ^^^^^^^^^^
+help: to declare that the `impl Trait` captures data from argument `self`, you can add an explicit `'_` lifetime bound
    |
 LL |     fn f(self: Pin<&Self>) -> impl Clone + '_ { self }
    |                                          ^^^^
 
 error: aborting due to previous error
 
+For more information about this error, try `rustc --explain E0759`.
diff --git a/src/test/ui/suggestions/lifetimes/missing-lifetimes-in-signature.stderr b/src/test/ui/suggestions/lifetimes/missing-lifetimes-in-signature.stderr
index 5cf170d566ca9..9ab060328537b 100644
--- a/src/test/ui/suggestions/lifetimes/missing-lifetimes-in-signature.stderr
+++ b/src/test/ui/suggestions/lifetimes/missing-lifetimes-in-signature.stderr
@@ -6,20 +6,23 @@ LL | fn baz<G: 'a, T>(g: G, dest: &mut T) -> impl FnOnce() + '_
    |        |
    |        help: consider introducing lifetime `'a` here: `'a,`
 
-error: cannot infer an appropriate lifetime
+error[E0759]: cannot infer an appropriate lifetime
   --> $DIR/missing-lifetimes-in-signature.rs:19:5
    |
 LL |   fn foo<G, T>(g: G, dest: &mut T) -> impl FnOnce()
-   |                            ------     ------------- ...is required to be `'static` by this...
-   |                            |
-   |                            data with this lifetime...
+   |                            ------ this data with an anonymous lifetime `'_`...
 ...
 LL | /     move || {
 LL | |         *dest = g.get();
 LL | |     }
-   | |_____^ ...and is captured here
+   | |_____^ ...is captured here...
    |
-help: to permit non-static references in an `impl Trait` value, you can add an explicit bound for the anonymous lifetime #1 defined on the function body at 15:1
+note: ...and is required to live as long as `'static` here
+  --> $DIR/missing-lifetimes-in-signature.rs:15:37
+   |
+LL | fn foo<G, T>(g: G, dest: &mut T) -> impl FnOnce()
+   |                                     ^^^^^^^^^^^^^
+help: to declare that the `impl Trait` captures data from argument `dest`, you can add an explicit `'_` lifetime bound
    |
 LL | fn foo<G, T>(g: G, dest: &mut T) -> impl FnOnce() + '_
    |                                                   ^^^^
@@ -122,5 +125,5 @@ LL | fn bak<'a, G, T>(g: G, dest: &'a mut T) -> impl FnOnce() + 'a
 
 error: aborting due to 7 previous errors
 
-Some errors have detailed explanations: E0261, E0309, E0621.
+Some errors have detailed explanations: E0261, E0309, E0621, E0759.
 For more information about an error, try `rustc --explain E0261`.
diff --git a/src/test/ui/suggestions/type-not-found-in-adt-field.rs b/src/test/ui/suggestions/type-not-found-in-adt-field.rs
new file mode 100644
index 0000000000000..4cbfe58d35703
--- /dev/null
+++ b/src/test/ui/suggestions/type-not-found-in-adt-field.rs
@@ -0,0 +1,9 @@
+struct Struct {
+    m: Vec<Someunknownname<String, ()>>, //~ ERROR cannot find type `Someunknownname` in this scope
+    //~^ NOTE not found in this scope
+}
+struct OtherStruct { //~ HELP you might be missing a type parameter
+    m: K, //~ ERROR cannot find type `K` in this scope
+    //~^ NOTE not found in this scope
+}
+fn main() {}
diff --git a/src/test/ui/suggestions/type-not-found-in-adt-field.stderr b/src/test/ui/suggestions/type-not-found-in-adt-field.stderr
new file mode 100644
index 0000000000000..e990fb5ba1210
--- /dev/null
+++ b/src/test/ui/suggestions/type-not-found-in-adt-field.stderr
@@ -0,0 +1,17 @@
+error[E0412]: cannot find type `Someunknownname` in this scope
+  --> $DIR/type-not-found-in-adt-field.rs:2:12
+   |
+LL |     m: Vec<Someunknownname<String, ()>>,
+   |            ^^^^^^^^^^^^^^^ not found in this scope
+
+error[E0412]: cannot find type `K` in this scope
+  --> $DIR/type-not-found-in-adt-field.rs:6:8
+   |
+LL | struct OtherStruct {
+   |                   - help: you might be missing a type parameter: `<K>`
+LL |     m: K,
+   |        ^ not found in this scope
+
+error: aborting due to 2 previous errors
+
+For more information about this error, try `rustc --explain E0412`.
diff --git a/src/test/ui/tag-variant-cast-non-nullary.fixed b/src/test/ui/tag-variant-cast-non-nullary.fixed
new file mode 100644
index 0000000000000..53e68c2ac6af6
--- /dev/null
+++ b/src/test/ui/tag-variant-cast-non-nullary.fixed
@@ -0,0 +1,20 @@
+// run-rustfix
+#![allow(dead_code, unused_variables)]
+enum NonNullary {
+    Nullary,
+    Other(isize),
+}
+
+impl From<NonNullary> for isize {
+    fn from(val: NonNullary) -> isize {
+        match val {
+            NonNullary::Nullary => 0,
+            NonNullary::Other(i) => i,
+        }
+    }
+}
+
+fn main() {
+    let v = NonNullary::Nullary;
+    let val = isize::from(v); //~ ERROR non-primitive cast: `NonNullary` as `isize` [E0605]
+}
diff --git a/src/test/ui/tag-variant-cast-non-nullary.rs b/src/test/ui/tag-variant-cast-non-nullary.rs
index bb34e82cdca37..0d0c6188ad114 100644
--- a/src/test/ui/tag-variant-cast-non-nullary.rs
+++ b/src/test/ui/tag-variant-cast-non-nullary.rs
@@ -1,8 +1,19 @@
+// run-rustfix
+#![allow(dead_code, unused_variables)]
 enum NonNullary {
     Nullary,
     Other(isize),
 }
 
+impl From<NonNullary> for isize {
+    fn from(val: NonNullary) -> isize {
+        match val {
+            NonNullary::Nullary => 0,
+            NonNullary::Other(i) => i,
+        }
+    }
+}
+
 fn main() {
     let v = NonNullary::Nullary;
     let val = v as isize; //~ ERROR non-primitive cast: `NonNullary` as `isize` [E0605]
diff --git a/src/test/ui/tag-variant-cast-non-nullary.stderr b/src/test/ui/tag-variant-cast-non-nullary.stderr
index 87ec20f20d789..ae2f5a7aead55 100644
--- a/src/test/ui/tag-variant-cast-non-nullary.stderr
+++ b/src/test/ui/tag-variant-cast-non-nullary.stderr
@@ -1,10 +1,10 @@
 error[E0605]: non-primitive cast: `NonNullary` as `isize`
-  --> $DIR/tag-variant-cast-non-nullary.rs:8:15
+  --> $DIR/tag-variant-cast-non-nullary.rs:19:15
    |
 LL |     let val = v as isize;
-   |               ^^^^^^^^^^
+   |               ^^^^^^^^^^ help: consider using the `From` trait instead: `isize::from(v)`
    |
-   = note: an `as` expression can only be used to convert between primitive types. Consider using the `From` trait
+   = note: an `as` expression can only be used to convert between primitive types or to coerce to a specific trait object
 
 error: aborting due to previous error
 
diff --git a/src/test/ui/type-alias-impl-trait/never_reveal_concrete_type.stderr b/src/test/ui/type-alias-impl-trait/never_reveal_concrete_type.stderr
index 4fbbf34752803..a6b7e35b488b1 100644
--- a/src/test/ui/type-alias-impl-trait/never_reveal_concrete_type.stderr
+++ b/src/test/ui/type-alias-impl-trait/never_reveal_concrete_type.stderr
@@ -16,9 +16,7 @@ error[E0605]: non-primitive cast: `impl std::fmt::Debug` as `&'static str`
   --> $DIR/never_reveal_concrete_type.rs:14:13
    |
 LL |     let _ = x as &'static str;
-   |             ^^^^^^^^^^^^^^^^^
-   |
-   = note: an `as` expression can only be used to convert between primitive types. Consider using the `From` trait
+   |             ^^^^^^^^^^^^^^^^^ an `as` expression can only be used to convert between primitive types or to coerce to a specific trait object
 
 error: aborting due to 2 previous errors
 
diff --git a/src/test/ui/underscore-lifetime/dyn-trait-underscore.stderr b/src/test/ui/underscore-lifetime/dyn-trait-underscore.stderr
index 3577dd59289e5..dda5de431d309 100644
--- a/src/test/ui/underscore-lifetime/dyn-trait-underscore.stderr
+++ b/src/test/ui/underscore-lifetime/dyn-trait-underscore.stderr
@@ -1,16 +1,17 @@
-error: cannot infer an appropriate lifetime
+error[E0759]: cannot infer an appropriate lifetime
   --> $DIR/dyn-trait-underscore.rs:8:20
    |
 LL | fn a<T>(items: &[T]) -> Box<dyn Iterator<Item=&T>> {
-   |                ---- data with this lifetime...
+   |                ---- this data with an anonymous lifetime `'_`...
 LL |     //                      ^^^^^^^^^^^^^^^^^^^^^ bound *here* defaults to `'static`
 LL |     Box::new(items.iter())
-   |     ---------------^^^^--- ...is captured and required to be `'static` here
+   |     ---------------^^^^--- ...is captured and required to live as long as `'static` here
    |
-help: to permit non-static references in a `dyn Trait` value, you can add an explicit bound for the anonymous lifetime #1 defined on the function body at 6:1
+help: to declare that the trait object captures data from argument `items`, you can add an explicit `'_` lifetime bound
    |
 LL | fn a<T>(items: &[T]) -> Box<dyn Iterator<Item=&T> + '_> {
    |                                                   ^^^^
 
 error: aborting due to previous error
 
+For more information about this error, try `rustc --explain E0759`.
diff --git a/src/test/ui/uninhabited/uninhabited-enum-cast.stderr b/src/test/ui/uninhabited/uninhabited-enum-cast.stderr
index a39af7832f8c9..a9f10dfec994a 100644
--- a/src/test/ui/uninhabited/uninhabited-enum-cast.stderr
+++ b/src/test/ui/uninhabited/uninhabited-enum-cast.stderr
@@ -2,9 +2,7 @@ error[E0605]: non-primitive cast: `E` as `isize`
   --> $DIR/uninhabited-enum-cast.rs:4:20
    |
 LL |     println!("{}", (e as isize).to_string());
-   |                    ^^^^^^^^^^^^
-   |
-   = note: an `as` expression can only be used to convert between primitive types. Consider using the `From` trait
+   |                    ^^^^^^^^^^^^ an `as` expression can only be used to convert between primitive types or to coerce to a specific trait object
 
 error: aborting due to previous error