Rollup of 8 pull requests

Cargo.lock

@@ -637,9 +637,9 @@ dependencies = [
 
 [[package]]
 name = "compiler_builtins"
-version = "0.1.36"
+version = "0.1.38"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "7cd0782e0a7da7598164153173e5a5d4d9b1da094473c98dce0ff91406112369"
+checksum = "475f939b731d862c8efe7001757c5d7c80978e00ef2923d60d90a6f0cb184c6b"
 dependencies = [
  "cc",
  "rustc-std-workspace-core",

compiler/rustc_builtin_macros/src/deriving/generic/mod.rs

@@ -597,10 +597,7 @@ impl<'a> TraitDef<'a> {
 
             let mut ty_params = params
                 .iter()
-                .filter_map(|param| match param.kind {
-                    ast::GenericParamKind::Type { .. } => Some(param),
-                    _ => None,
-                })
+                .filter(|param| matches!(param.kind,  ast::GenericParamKind::Type{..}))
                 .peekable();
 
             if ty_params.peek().is_some() {

compiler/rustc_codegen_llvm/src/intrinsic.rs

@@ -854,8 +854,8 @@ fn generic_simd_intrinsic(
         ));
     }
 
-    if name_str.starts_with("simd_shuffle") {
-        let n: u64 = name_str["simd_shuffle".len()..].parse().unwrap_or_else(|_| {
+    if let Some(stripped) = name_str.strip_prefix("simd_shuffle") {
+        let n: u64 = stripped.parse().unwrap_or_else(|_| {
             span_bug!(span, "bad `simd_shuffle` instruction only caught in codegen?")
         });
 

compiler/rustc_llvm/build.rs

@@ -201,10 +201,10 @@ fn main() {
     cmd.args(&components);
 
     for lib in output(&mut cmd).split_whitespace() {
-        let name = if lib.starts_with("-l") {
-            &lib[2..]
-        } else if lib.starts_with('-') {
-            &lib[1..]
+        let name = if let Some(stripped) = lib.strip_prefix("-l") {
+            stripped
+        } else if let Some(stripped) = lib.strip_prefix('-') {
+            stripped
         } else if Path::new(lib).exists() {
             // On MSVC llvm-config will print the full name to libraries, but
             // we're only interested in the name part
@@ -241,17 +241,17 @@ fn main() {
     cmd.arg(llvm_link_arg).arg("--ldflags");
     for lib in output(&mut cmd).split_whitespace() {
         if is_crossed {
-            if lib.starts_with("-LIBPATH:") {
-                println!("cargo:rustc-link-search=native={}", lib[9..].replace(&host, &target));
-            } else if lib.starts_with("-L") {
-                println!("cargo:rustc-link-search=native={}", lib[2..].replace(&host, &target));
+            if let Some(stripped) = lib.strip_prefix("-LIBPATH:") {
+                println!("cargo:rustc-link-search=native={}", stripped.replace(&host, &target));
+            } else if let Some(stripped) = lib.strip_prefix("-L") {
+                println!("cargo:rustc-link-search=native={}", stripped.replace(&host, &target));
             }
-        } else if lib.starts_with("-LIBPATH:") {
-            println!("cargo:rustc-link-search=native={}", &lib[9..]);
-        } else if lib.starts_with("-l") {
-            println!("cargo:rustc-link-lib={}", &lib[2..]);
-        } else if lib.starts_with("-L") {
-            println!("cargo:rustc-link-search=native={}", &lib[2..]);
+        } else if let Some(stripped) = lib.strip_prefix("-LIBPATH:") {
+            println!("cargo:rustc-link-search=native={}", stripped);
+        } else if let Some(stripped) = lib.strip_prefix("-l") {
+            println!("cargo:rustc-link-lib={}", stripped);
+        } else if let Some(stripped) = lib.strip_prefix("-L") {
+            println!("cargo:rustc-link-search=native={}", stripped);
         }
     }
 
@@ -262,10 +262,10 @@ fn main() {
     let llvm_linker_flags = tracked_env_var_os("LLVM_LINKER_FLAGS");
     if let Some(s) = llvm_linker_flags {
         for lib in s.into_string().unwrap().split_whitespace() {
-            if lib.starts_with("-l") {
-                println!("cargo:rustc-link-lib={}", &lib[2..]);
-            } else if lib.starts_with("-L") {
-                println!("cargo:rustc-link-search=native={}", &lib[2..]);
+            if let Some(stripped) = lib.strip_prefix("-l") {
+                println!("cargo:rustc-link-lib={}", stripped);
+            } else if let Some(stripped) = lib.strip_prefix("-L") {
+                println!("cargo:rustc-link-search=native={}", stripped);
             }
         }
     }

compiler/rustc_mir/src/interpret/machine.rs

@@ -9,6 +9,7 @@ use std::hash::Hash;
 use rustc_middle::mir;
 use rustc_middle::ty::{self, Ty};
 use rustc_span::def_id::DefId;
+use rustc_target::abi::Size;
 
 use super::{
     AllocId, Allocation, AllocationExtra, CheckInAllocMsg, Frame, ImmTy, InterpCx, InterpResult,
@@ -299,6 +300,15 @@ pub trait Machine<'mir, 'tcx>: Sized {
         Ok(())
     }
 
+    /// Called after initializing static memory using the interpreter.
+    fn after_static_mem_initialized(
+        _ecx: &mut InterpCx<'mir, 'tcx, Self>,
+        _ptr: Pointer<Self::PointerTag>,
+        _size: Size,
+    ) -> InterpResult<'tcx> {
+        Ok(())
+    }
+
     /// Executes a retagging operation
     #[inline]
     fn retag(

compiler/rustc_mir/src/interpret/traits.rs

@@ -56,11 +56,8 @@ impl<'mir, 'tcx: 'mir, M: Machine<'mir, 'tcx>> InterpCx<'mir, 'tcx, M> {
         // If you touch this code, be sure to also make the corresponding changes to
         // `get_vtable` in `rust_codegen_llvm/meth.rs`.
         // /////////////////////////////////////////////////////////////////////////////////////////
-        let vtable = self.memory.allocate(
-            ptr_size * u64::try_from(methods.len()).unwrap().checked_add(3).unwrap(),
-            ptr_align,
-            MemoryKind::Vtable,
-        );
+        let vtable_size = ptr_size * u64::try_from(methods.len()).unwrap().checked_add(3).unwrap();
+        let vtable = self.memory.allocate(vtable_size, ptr_align, MemoryKind::Vtable);
 
         let drop = Instance::resolve_drop_in_place(tcx, ty);
         let drop = self.memory.create_fn_alloc(FnVal::Instance(drop));
@@ -93,6 +90,8 @@ impl<'mir, 'tcx: 'mir, M: Machine<'mir, 'tcx>> InterpCx<'mir, 'tcx, M> {
             }
         }
 
+        M::after_static_mem_initialized(self, vtable, vtable_size)?;
+
         self.memory.mark_immutable(vtable.alloc_id)?;
         assert!(self.vtables.insert((ty, poly_trait_ref), vtable).is_none());
 

compiler/rustc_mir/src/transform/coverage/debug.rs

@@ -285,7 +285,7 @@ impl DebugCounters {
                 ),
             };
             counters
-                .insert(id.into(), DebugCounter::new(counter_kind.clone(), some_block_label))
+                .insert(id, DebugCounter::new(counter_kind.clone(), some_block_label))
                 .expect_none(
                     "attempt to add the same counter_kind to DebugCounters more than once",
                 );
@@ -340,7 +340,7 @@ impl DebugCounters {
         if self.some_counters.is_some() && (counter_format.block || !counter_format.id) {
             let counters = self.some_counters.as_ref().unwrap();
             if let Some(DebugCounter { some_block_label: Some(block_label), .. }) =
-                counters.get(&id.into())
+                counters.get(&id)
             {
                 return if counter_format.id {
                     format!("{}#{}", block_label, id.index())

compiler/rustc_mir/src/transform/early_otherwise_branch.rs

@@ -216,9 +216,10 @@ impl<'a, 'tcx> Helper<'a, 'tcx> {
         let discr = self.find_switch_discriminant_info(bb, switch)?;
 
         // go through each target, finding a discriminant read, and a switch
-        let results = discr.targets_with_values.iter().map(|(value, target)| {
-            self.find_discriminant_switch_pairing(&discr, target.clone(), value.clone())
-        });
+        let results = discr
+            .targets_with_values
+            .iter()
+            .map(|(value, target)| self.find_discriminant_switch_pairing(&discr, *target, *value));
 
         // if the optimization did not apply for one of the targets, then abort
         if results.clone().any(|x| x.is_none()) || results.len() == 0 {

compiler/rustc_mir_build/src/build/scope.rs

@@ -616,8 +616,9 @@ impl<'a, 'tcx> Builder<'a, 'tcx> {
                 debug!("stmt_expr Break val block_context.push(SubExpr)");
                 self.block_context.push(BlockFrame::SubExpr);
                 unpack!(block = self.into(destination, dest_scope, block, value));
-                dest_scope
-                    .map(|scope| self.unschedule_drop(scope, destination.as_local().unwrap()));
+                if let Some(scope) = dest_scope {
+                    self.unschedule_drop(scope, destination.as_local().unwrap())
+                };
                 self.block_context.pop();
             } else {
                 self.cfg.push_assign_unit(block, source_info, destination, self.hir.tcx())

compiler/rustc_session/src/session.rs

@@ -1109,10 +1109,7 @@ impl Session {
     }
 
     pub fn link_dead_code(&self) -> bool {
-        match self.opts.cg.link_dead_code {
-            Some(explicitly_set) => explicitly_set,
-            None => false,
-        }
+        self.opts.cg.link_dead_code.unwrap_or(false)
     }
 
     pub fn mark_attr_known(&self, attr: &Attribute) {

compiler/rustc_trait_selection/src/traits/error_reporting/suggestions.rs

@@ -1448,31 +1448,30 @@ impl<'a, 'tcx> InferCtxtExt<'tcx> for InferCtxt<'a, 'tcx> {
             });
         };
 
-        typeck_results
+        if let Some(cause) = typeck_results
             .generator_interior_types
             .iter()
             .find(|ty::GeneratorInteriorTypeCause { ty, .. }| ty_matches(ty))
-            .map(|cause| {
-                // Check to see if any awaited expressions have the target type.
-                let from_awaited_ty = visitor
-                    .awaits
-                    .into_iter()
-                    .map(|id| hir.expect_expr(id))
-                    .find(|await_expr| {
-                        let ty = typeck_results.expr_ty_adjusted(&await_expr);
-                        debug!(
-                            "maybe_note_obligation_cause_for_async_await: await_expr={:?}",
-                            await_expr
-                        );
-                        ty_matches(ty)
-                    })
-                    .map(|expr| expr.span);
-                let ty::GeneratorInteriorTypeCause { span, scope_span, yield_span, expr, .. } =
-                    cause;
+        {
+            // Check to see if any awaited expressions have the target type.
+            let from_awaited_ty = visitor
+                .awaits
+                .into_iter()
+                .map(|id| hir.expect_expr(id))
+                .find(|await_expr| {
+                    let ty = typeck_results.expr_ty_adjusted(&await_expr);
+                    debug!(
+                        "maybe_note_obligation_cause_for_async_await: await_expr={:?}",
+                        await_expr
+                    );
+                    ty_matches(ty)
+                })
+                .map(|expr| expr.span);
+            let ty::GeneratorInteriorTypeCause { span, scope_span, yield_span, expr, .. } = cause;
 
-                interior_or_upvar_span = Some(GeneratorInteriorOrUpvar::Interior(*span));
-                interior_extra_info = Some((*scope_span, *yield_span, *expr, from_awaited_ty));
-            });
+            interior_or_upvar_span = Some(GeneratorInteriorOrUpvar::Interior(*span));
+            interior_extra_info = Some((*scope_span, *yield_span, *expr, from_awaited_ty));
+        };
 
         debug!(
             "maybe_note_obligation_cause_for_async_await: interior_or_upvar={:?} \

compiler/rustc_trait_selection/src/traits/select/confirmation.rs

@@ -447,7 +447,7 @@ impl<'cx, 'tcx> SelectionContext<'cx, 'tcx> {
                 );
                 nested.push(Obligation::new(
                     obligation.cause.clone(),
-                    obligation.param_env.clone(),
+                    obligation.param_env,
                     normalized_super_trait,
                 ));
             }
@@ -485,7 +485,7 @@ impl<'cx, 'tcx> SelectionContext<'cx, 'tcx> {
                 );
                 nested.push(Obligation::new(
                     obligation.cause.clone(),
-                    obligation.param_env.clone(),
+                    obligation.param_env,
                     normalized_bound,
                 ));
             }

compiler/rustc_type_ir/src/lib.rs

@@ -119,7 +119,7 @@ rustc_index::newtype_index! {
     /// Bruijn index of 0, meaning "the innermost binder" (in this case, a
     /// fn). The region `'a` that appears in the second argument type (`&'a
     /// isize`) would then be assigned a De Bruijn index of 1, meaning "the
-    /// second-innermost binder". (These indices are written on the arrays
+    /// second-innermost binder". (These indices are written on the arrows
     /// in the diagram).
     ///
     /// What is interesting is that De Bruijn index attached to a particular

compiler/rustc_typeck/src/check/upvar.rs

@@ -294,17 +294,16 @@ impl<'a, 'tcx> FnCtxt<'a, 'tcx> {
 
                     closure_captures.insert(*var_hir_id, upvar_id);
 
-                    let new_capture_kind = if let Some(capture_kind) =
-                        upvar_capture_map.get(&upvar_id)
-                    {
-                        // upvar_capture_map only stores the UpvarCapture (CaptureKind),
-                        // so we create a fake capture info with no expression.
-                        let fake_capture_info =
-                            ty::CaptureInfo { expr_id: None, capture_kind: capture_kind.clone() };
-                        determine_capture_info(fake_capture_info, capture_info).capture_kind
-                    } else {
-                        capture_info.capture_kind
-                    };
+                    let new_capture_kind =
+                        if let Some(capture_kind) = upvar_capture_map.get(&upvar_id) {
+                            // upvar_capture_map only stores the UpvarCapture (CaptureKind),
+                            // so we create a fake capture info with no expression.
+                            let fake_capture_info =
+                                ty::CaptureInfo { expr_id: None, capture_kind: *capture_kind };
+                            determine_capture_info(fake_capture_info, capture_info).capture_kind
+                        } else {
+                            capture_info.capture_kind
+                        };
                     upvar_capture_map.insert(upvar_id, new_capture_kind);
                 }
             }

compiler/rustc_typeck/src/collect.rs

@@ -2141,13 +2141,8 @@ fn explicit_predicates_of(tcx: TyCtxt<'_>, def_id: DefId) -> ty::GenericPredicat
             // * It must be an associated type for this trait (*not* a
             //   supertrait).
             if let ty::Projection(projection) = ty.kind() {
-                if projection.substs == trait_identity_substs
+                projection.substs == trait_identity_substs
                     && tcx.associated_item(projection.item_def_id).container.id() == def_id
-                {
-                    true
-                } else {
-                    false
-                }
             } else {
                 false
             }

library/alloc/Cargo.toml

@@ -8,7 +8,7 @@ edition = "2018"
 
 [dependencies]
 core = { path = "../core" }
-compiler_builtins = { version = "0.1.10", features = ['rustc-dep-of-std'] }
+compiler_builtins = { version = "0.1.38", features = ['rustc-dep-of-std'] }
 
 [dev-dependencies]
 rand = "0.7"
@@ -31,5 +31,5 @@ harness = false
 [features]
 compiler-builtins-mem = ['compiler_builtins/mem']
 compiler-builtins-c = ["compiler_builtins/c"]
-compiler-builtins-asm = ["compiler_builtins/asm"]
+compiler-builtins-no-asm = ["compiler_builtins/no-asm"]
 compiler-builtins-mangled-names = ["compiler_builtins/mangled-names"]

library/core/src/iter/mod.rs

@@ -206,6 +206,51 @@
 //! 2. If you're creating a collection, implementing [`IntoIterator`] for it
 //!    will allow your collection to be used with the `for` loop.
 //!
+//! # Iterating by reference
+//!
+//! Since [`into_iter()`] takes `self` by value, using a `for` loop to iterate
+//! over a collection consumes that collection. Often, you may want to iterate
+//! over a collection without consuming it. Many collections offer methods that
+//! provide iterators over references, conventionally called `iter()` and
+//! `iter_mut()` respectively:
+//!
+//! ```
+//! let mut values = vec![41];
+//! for x in values.iter_mut() {
+//!     *x += 1;
+//! }
+//! for x in values.iter() {
+//!     assert_eq!(*x, 42);
+//! }
+//! assert_eq!(values.len(), 1); // `values` is still owned by this function.
+//! ```
+//!
+//! If a collection type `C` provides `iter()`, it usually also implements
+//! `IntoIterator` for `&C`, with an implementation that just calls `iter()`.
+//! Likewise, a collection `C` that provides `iter_mut()` generally implements
+//! `IntoIterator` for `&mut C` by delegating to `iter_mut()`. This enables a
+//! convenient shorthand:
+//!
+//! ```
+//! let mut values = vec![41];
+//! for x in &mut values { // same as `values.iter_mut()`
+//!     *x += 1;
+//! }
+//! for x in &values { // same as `values.iter()`
+//!     assert_eq!(*x, 42);
+//! }
+//! assert_eq!(values.len(), 1);
+//! ```
+//!
+//! While many collections offer `iter()`, not all offer `iter_mut()`. For
+//! example, mutating the keys of a [`HashSet<T>`] or [`HashMap<K, V>`] could
+//! put the collection into an inconsistent state if the key hashes change, so
+//! these collections only offer `iter()`.
+//!
+//! [`into_iter()`]: IntoIterator::into_iter
+//! [`HashSet<T>`]: ../../std/collections/struct.HashSet.html
+//! [`HashMap<K, V>`]: ../../std/collections/struct.HashMap.html
+//!
 //! # Adapters
 //!
 //! Functions which take an [`Iterator`] and return another [`Iterator`] are