From fb4095df94bf07dc745a0c0e07adc93b52f04673 Mon Sep 17 00:00:00 2001
From: Michael Hewson <michael@michaelhewson.ca>
Date: Sat, 26 Oct 2019 16:44:06 -0400
Subject: [PATCH 01/10] Update comments re type parameter hack in object safety

To check if a method's receiver type is object safe, we create a new receiver type by substituting in a bogus type parameter (let's call it `U`) for `Self`, and checking that the unmodified receiver type implements `DispatchFromDyn<receiver type with Self = U>`. It would be better to use `dyn Trait` directly, and the only reason we don't is because it triggers another check that `Trait` is object safe, resulting in a query cycle. Once the feature `object_safe_for_dispatch` (tracking issue https://github.com/rust-lang/rust/issues/43561) is stabilized, this will no longer be the case, and we'll be able to use `dyn Trait` as the unsized `Self` type. I've updated the comments in object_safety.rs accordingly.
---
 src/librustc/traits/object_safety.rs | 12 +++++++-----
 1 file changed, 7 insertions(+), 5 deletions(-)

diff --git a/src/librustc/traits/object_safety.rs b/src/librustc/traits/object_safety.rs
index e42c3a63541cc..8ded1417ee570 100644
--- a/src/librustc/traits/object_safety.rs
+++ b/src/librustc/traits/object_safety.rs
@@ -520,9 +520,11 @@ impl<'tcx> TyCtxt<'tcx> {
     /// a pointer.
     ///
     /// In practice, we cannot use `dyn Trait` explicitly in the obligation because it would result
-    /// in a new check that `Trait` is object safe, creating a cycle. So instead, we fudge a little
-    /// by introducing a new type parameter `U` such that `Self: Unsize<U>` and `U: Trait + ?Sized`,
-    /// and use `U` in place of `dyn Trait`. Written as a chalk-style query:
+    /// in a new check that `Trait` is object safe, creating a cycle (until object_safe_for_dispatch
+    /// is stabilized, see tracking issue https://github.com/rust-lang/rust/issues/43561).
+    /// Instead, we fudge a little by introducing a new type parameter `U` such that
+    /// `Self: Unsize<U>` and `U: Trait + ?Sized`, and use `U` in place of `dyn Trait`.
+    /// Written as a chalk-style query:
     ///
     ///     forall (U: Trait + ?Sized) {
     ///         if (Self: Unsize<U>) {
@@ -556,8 +558,8 @@ impl<'tcx> TyCtxt<'tcx> {
 
         // the type `U` in the query
         // use a bogus type parameter to mimick a forall(U) query using u32::MAX for now.
-        // FIXME(mikeyhew) this is a total hack, and we should replace it when real forall queries
-        // are implemented
+        // FIXME(mikeyhew) this is a total hack. Once object_safe_for_dispatch is stabilized, we can
+        // replace this with `dyn Trait`
         let unsized_self_ty: Ty<'tcx> = self.mk_ty_param(
             ::std::u32::MAX,
             Symbol::intern("RustaceansAreAwesome"),

From 58b67c88119970b7c96f678e3afaab00f086f612 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Esteban=20K=C3=BCber?= <esteban@kuber.com.ar>
Date: Mon, 28 Oct 2019 16:58:27 -0700
Subject: [PATCH 02/10] Use structured suggestion for unnecessary bounds in
 type aliases

---
 src/librustc_lint/builtin.rs                  | 17 ++++--
 .../associated-type-bounds/type-alias.stderr  | 60 +++++++++++++++----
 .../ui/privacy/private-in-public-warn.stderr  | 10 +++-
 .../trivial-bounds-inconsistent.stderr        |  5 +-
 src/test/ui/type/type-alias-bounds.stderr     | 45 +++++++++++---
 5 files changed, 109 insertions(+), 28 deletions(-)

diff --git a/src/librustc_lint/builtin.rs b/src/librustc_lint/builtin.rs
index 7c19449f96b86..e3c3966c2f5e0 100644
--- a/src/librustc_lint/builtin.rs
+++ b/src/librustc_lint/builtin.rs
@@ -1125,8 +1125,12 @@ impl<'a, 'tcx> LateLintPass<'a, 'tcx> for TypeAliasBounds {
                 .map(|pred| pred.span()).collect();
             let mut err = cx.struct_span_lint(TYPE_ALIAS_BOUNDS, spans,
                 "where clauses are not enforced in type aliases");
-            err.help("the clause will not be checked when the type alias is used, \
-                      and should be removed");
+            err.span_suggestion(
+                type_alias_generics.where_clause.span_for_predicates_or_empty_place(),
+                "the clause will not be checked when the type alias is used, and should be removed",
+                String::new(),
+                Applicability::MachineApplicable,
+            );
             if !suggested_changing_assoc_types {
                 TypeAliasBounds::suggest_changing_assoc_types(ty, &mut err);
                 suggested_changing_assoc_types = true;
@@ -1136,14 +1140,19 @@ impl<'a, 'tcx> LateLintPass<'a, 'tcx> for TypeAliasBounds {
         // The parameters must not have bounds
         for param in type_alias_generics.params.iter() {
             let spans: Vec<_> = param.bounds.iter().map(|b| b.span()).collect();
+            let suggestion = spans.iter().map(|sp| {
+                let start = param.span.between(*sp); // Include the `:` in `T: Bound`.
+                (start.to(*sp), String::new())
+            }).collect();
             if !spans.is_empty() {
                 let mut err = cx.struct_span_lint(
                     TYPE_ALIAS_BOUNDS,
                     spans,
                     "bounds on generic parameters are not enforced in type aliases",
                 );
-                err.help("the bound will not be checked when the type alias is used, \
-                          and should be removed");
+                let msg = "the bound will not be checked when the type alias is used, \
+                           and should be removed";
+                err.multipart_suggestion(&msg, suggestion, Applicability::MachineApplicable);
                 if !suggested_changing_assoc_types {
                     TypeAliasBounds::suggest_changing_assoc_types(ty, &mut err);
                     suggested_changing_assoc_types = true;
diff --git a/src/test/ui/associated-type-bounds/type-alias.stderr b/src/test/ui/associated-type-bounds/type-alias.stderr
index a3fa97f54e385..7f58f7f73e38c 100644
--- a/src/test/ui/associated-type-bounds/type-alias.stderr
+++ b/src/test/ui/associated-type-bounds/type-alias.stderr
@@ -5,7 +5,10 @@ LL | type _TaWhere1<T> where T: Iterator<Item: Copy> = T;
    |                         ^^^^^^^^^^^^^^^^^^^^^^^
    |
    = note: `#[warn(type_alias_bounds)]` on by default
-   = help: the clause will not be checked when the type alias is used, and should be removed
+help: the clause will not be checked when the type alias is used, and should be removed
+   |
+LL | type _TaWhere1<T>  = T;
+   |                  --
 
 warning: where clauses are not enforced in type aliases
   --> $DIR/type-alias.rs:6:25
@@ -13,7 +16,10 @@ warning: where clauses are not enforced in type aliases
 LL | type _TaWhere2<T> where T: Iterator<Item: 'static> = T;
    |                         ^^^^^^^^^^^^^^^^^^^^^^^^^^
    |
-   = help: the clause will not be checked when the type alias is used, and should be removed
+help: the clause will not be checked when the type alias is used, and should be removed
+   |
+LL | type _TaWhere2<T>  = T;
+   |                  --
 
 warning: where clauses are not enforced in type aliases
   --> $DIR/type-alias.rs:7:25
@@ -21,7 +27,10 @@ warning: where clauses are not enforced in type aliases
 LL | type _TaWhere3<T> where T: Iterator<Item: 'static> = T;
    |                         ^^^^^^^^^^^^^^^^^^^^^^^^^^
    |
-   = help: the clause will not be checked when the type alias is used, and should be removed
+help: the clause will not be checked when the type alias is used, and should be removed
+   |
+LL | type _TaWhere3<T>  = T;
+   |                  --
 
 warning: where clauses are not enforced in type aliases
   --> $DIR/type-alias.rs:8:25
@@ -29,7 +38,10 @@ warning: where clauses are not enforced in type aliases
 LL | type _TaWhere4<T> where T: Iterator<Item: 'static + Copy + Send> = T;
    |                         ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
    |
-   = help: the clause will not be checked when the type alias is used, and should be removed
+help: the clause will not be checked when the type alias is used, and should be removed
+   |
+LL | type _TaWhere4<T>  = T;
+   |                  --
 
 warning: where clauses are not enforced in type aliases
   --> $DIR/type-alias.rs:9:25
@@ -37,7 +49,10 @@ warning: where clauses are not enforced in type aliases
 LL | type _TaWhere5<T> where T: Iterator<Item: for<'a> Into<&'a u8>> = T;
    |                         ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
    |
-   = help: the clause will not be checked when the type alias is used, and should be removed
+help: the clause will not be checked when the type alias is used, and should be removed
+   |
+LL | type _TaWhere5<T>  = T;
+   |                  --
 
 warning: where clauses are not enforced in type aliases
   --> $DIR/type-alias.rs:10:25
@@ -45,7 +60,10 @@ warning: where clauses are not enforced in type aliases
 LL | type _TaWhere6<T> where T: Iterator<Item: Iterator<Item: Copy>> = T;
    |                         ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
    |
-   = help: the clause will not be checked when the type alias is used, and should be removed
+help: the clause will not be checked when the type alias is used, and should be removed
+   |
+LL | type _TaWhere6<T>  = T;
+   |                  --
 
 warning: bounds on generic parameters are not enforced in type aliases
   --> $DIR/type-alias.rs:12:20
@@ -53,7 +71,10 @@ warning: bounds on generic parameters are not enforced in type aliases
 LL | type _TaInline1<T: Iterator<Item: Copy>> = T;
    |                    ^^^^^^^^^^^^^^^^^^^^
    |
-   = help: the bound will not be checked when the type alias is used, and should be removed
+help: the bound will not be checked when the type alias is used, and should be removed
+   |
+LL | type _TaInline1<T> = T;
+   |                 --
 
 warning: bounds on generic parameters are not enforced in type aliases
   --> $DIR/type-alias.rs:13:20
@@ -61,7 +82,10 @@ warning: bounds on generic parameters are not enforced in type aliases
 LL | type _TaInline2<T: Iterator<Item: 'static>> = T;
    |                    ^^^^^^^^^^^^^^^^^^^^^^^
    |
-   = help: the bound will not be checked when the type alias is used, and should be removed
+help: the bound will not be checked when the type alias is used, and should be removed
+   |
+LL | type _TaInline2<T> = T;
+   |                 --
 
 warning: bounds on generic parameters are not enforced in type aliases
   --> $DIR/type-alias.rs:14:20
@@ -69,7 +93,10 @@ warning: bounds on generic parameters are not enforced in type aliases
 LL | type _TaInline3<T: Iterator<Item: 'static>> = T;
    |                    ^^^^^^^^^^^^^^^^^^^^^^^
    |
-   = help: the bound will not be checked when the type alias is used, and should be removed
+help: the bound will not be checked when the type alias is used, and should be removed
+   |
+LL | type _TaInline3<T> = T;
+   |                 --
 
 warning: bounds on generic parameters are not enforced in type aliases
   --> $DIR/type-alias.rs:15:20
@@ -77,7 +104,10 @@ warning: bounds on generic parameters are not enforced in type aliases
 LL | type _TaInline4<T: Iterator<Item: 'static + Copy + Send>> = T;
    |                    ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
    |
-   = help: the bound will not be checked when the type alias is used, and should be removed
+help: the bound will not be checked when the type alias is used, and should be removed
+   |
+LL | type _TaInline4<T> = T;
+   |                 --
 
 warning: bounds on generic parameters are not enforced in type aliases
   --> $DIR/type-alias.rs:16:20
@@ -85,7 +115,10 @@ warning: bounds on generic parameters are not enforced in type aliases
 LL | type _TaInline5<T: Iterator<Item: for<'a> Into<&'a u8>>> = T;
    |                    ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
    |
-   = help: the bound will not be checked when the type alias is used, and should be removed
+help: the bound will not be checked when the type alias is used, and should be removed
+   |
+LL | type _TaInline5<T> = T;
+   |                 --
 
 warning: bounds on generic parameters are not enforced in type aliases
   --> $DIR/type-alias.rs:17:20
@@ -93,5 +126,8 @@ warning: bounds on generic parameters are not enforced in type aliases
 LL | type _TaInline6<T: Iterator<Item: Iterator<Item: Copy>>> = T;
    |                    ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
    |
-   = help: the bound will not be checked when the type alias is used, and should be removed
+help: the bound will not be checked when the type alias is used, and should be removed
+   |
+LL | type _TaInline6<T> = T;
+   |                 --
 
diff --git a/src/test/ui/privacy/private-in-public-warn.stderr b/src/test/ui/privacy/private-in-public-warn.stderr
index 9741f3b6d0d41..40aa47a7246c4 100644
--- a/src/test/ui/privacy/private-in-public-warn.stderr
+++ b/src/test/ui/privacy/private-in-public-warn.stderr
@@ -340,7 +340,10 @@ LL |     pub type Alias<T: PrivTr> = T;
    |                       ^^^^^^
    |
    = note: `#[warn(type_alias_bounds)]` on by default
-   = help: the bound will not be checked when the type alias is used, and should be removed
+help: the bound will not be checked when the type alias is used, and should be removed
+   |
+LL |     pub type Alias<T> = T;
+   |                    --
 
 warning: where clauses are not enforced in type aliases
   --> $DIR/private-in-public-warn.rs:75:29
@@ -348,7 +351,10 @@ warning: where clauses are not enforced in type aliases
 LL |     pub type Alias<T> where T: PrivTr = T;
    |                             ^^^^^^^^^
    |
-   = help: the clause will not be checked when the type alias is used, and should be removed
+help: the clause will not be checked when the type alias is used, and should be removed
+   |
+LL |     pub type Alias<T>  = T;
+   |                      --
 
 error: aborting due to 36 previous errors
 
diff --git a/src/test/ui/trivial-bounds/trivial-bounds-inconsistent.stderr b/src/test/ui/trivial-bounds/trivial-bounds-inconsistent.stderr
index 0eb0769c57071..cb8bad6d9e74d 100644
--- a/src/test/ui/trivial-bounds/trivial-bounds-inconsistent.stderr
+++ b/src/test/ui/trivial-bounds/trivial-bounds-inconsistent.stderr
@@ -31,7 +31,10 @@ LL | type Y where i32: Foo = ();
    |              ^^^^^^^^
    |
    = note: `#[warn(type_alias_bounds)]` on by default
-   = help: the clause will not be checked when the type alias is used, and should be removed
+help: the clause will not be checked when the type alias is used, and should be removed
+   |
+LL | type Y  = ();
+   |       --
 
 warning: Trait bound i32: Foo does not depend on any type or lifetime parameters
   --> $DIR/trivial-bounds-inconsistent.rs:22:19
diff --git a/src/test/ui/type/type-alias-bounds.stderr b/src/test/ui/type/type-alias-bounds.stderr
index dbb7b92563ab8..c381d30c64f14 100644
--- a/src/test/ui/type/type-alias-bounds.stderr
+++ b/src/test/ui/type/type-alias-bounds.stderr
@@ -5,7 +5,10 @@ LL | type SVec<T: Send + Send> = Vec<T>;
    |              ^^^^   ^^^^
    |
    = note: `#[warn(type_alias_bounds)]` on by default
-   = help: the bound will not be checked when the type alias is used, and should be removed
+help: the bound will not be checked when the type alias is used, and should be removed
+   |
+LL | type SVec<T> = Vec<T>;
+   |     --    --
 
 warning: where clauses are not enforced in type aliases
   --> $DIR/type-alias-bounds.rs:10:21
@@ -13,7 +16,10 @@ warning: where clauses are not enforced in type aliases
 LL | type S2Vec<T> where T: Send = Vec<T>;
    |                     ^^^^^^^
    |
-   = help: the clause will not be checked when the type alias is used, and should be removed
+help: the clause will not be checked when the type alias is used, and should be removed
+   |
+LL | type S2Vec<T>  = Vec<T>;
+   |              --
 
 warning: bounds on generic parameters are not enforced in type aliases
   --> $DIR/type-alias-bounds.rs:12:19
@@ -21,7 +27,10 @@ warning: bounds on generic parameters are not enforced in type aliases
 LL | type VVec<'b, 'a: 'b + 'b> = (&'b u32, Vec<&'a i32>);
    |                   ^^   ^^
    |
-   = help: the bound will not be checked when the type alias is used, and should be removed
+help: the bound will not be checked when the type alias is used, and should be removed
+   |
+LL | type VVec<'b, 'a> = (&'b u32, Vec<&'a i32>);
+   |            --  --
 
 warning: bounds on generic parameters are not enforced in type aliases
   --> $DIR/type-alias-bounds.rs:14:18
@@ -29,7 +38,10 @@ warning: bounds on generic parameters are not enforced in type aliases
 LL | type WVec<'b, T: 'b + 'b> = (&'b u32, Vec<T>);
    |                  ^^   ^^
    |
-   = help: the bound will not be checked when the type alias is used, and should be removed
+help: the bound will not be checked when the type alias is used, and should be removed
+   |
+LL | type WVec<'b, T> = (&'b u32, Vec<T>);
+   |           --  --
 
 warning: where clauses are not enforced in type aliases
   --> $DIR/type-alias-bounds.rs:16:25
@@ -37,7 +49,10 @@ warning: where clauses are not enforced in type aliases
 LL | type W2Vec<'b, T> where T: 'b, T: 'b = (&'b u32, Vec<T>);
    |                         ^^^^^  ^^^^^
    |
-   = help: the clause will not be checked when the type alias is used, and should be removed
+help: the clause will not be checked when the type alias is used, and should be removed
+   |
+LL | type W2Vec<'b, T>  = (&'b u32, Vec<T>);
+   |                  --
 
 warning: bounds on generic parameters are not enforced in type aliases
   --> $DIR/type-alias-bounds.rs:47:12
@@ -45,12 +60,15 @@ warning: bounds on generic parameters are not enforced in type aliases
 LL | type T1<U: Bound> = U::Assoc;
    |            ^^^^^
    |
-   = help: the bound will not be checked when the type alias is used, and should be removed
 help: use fully disambiguated paths (i.e., `<T as Trait>::Assoc`) to refer to associated types in type aliases
   --> $DIR/type-alias-bounds.rs:47:21
    |
 LL | type T1<U: Bound> = U::Assoc;
    |                     ^^^^^^^^
+help: the bound will not be checked when the type alias is used, and should be removed
+   |
+LL | type T1<U> = U::Assoc;
+   |         --
 
 warning: where clauses are not enforced in type aliases
   --> $DIR/type-alias-bounds.rs:48:18
@@ -58,12 +76,15 @@ warning: where clauses are not enforced in type aliases
 LL | type T2<U> where U: Bound = U::Assoc;
    |                  ^^^^^^^^
    |
-   = help: the clause will not be checked when the type alias is used, and should be removed
 help: use fully disambiguated paths (i.e., `<T as Trait>::Assoc`) to refer to associated types in type aliases
   --> $DIR/type-alias-bounds.rs:48:29
    |
 LL | type T2<U> where U: Bound = U::Assoc;
    |                             ^^^^^^^^
+help: the clause will not be checked when the type alias is used, and should be removed
+   |
+LL | type T2<U>  = U::Assoc;
+   |           --
 
 warning: bounds on generic parameters are not enforced in type aliases
   --> $DIR/type-alias-bounds.rs:56:12
@@ -71,7 +92,10 @@ warning: bounds on generic parameters are not enforced in type aliases
 LL | type T5<U: Bound> = <U as Bound>::Assoc;
    |            ^^^^^
    |
-   = help: the bound will not be checked when the type alias is used, and should be removed
+help: the bound will not be checked when the type alias is used, and should be removed
+   |
+LL | type T5<U> = <U as Bound>::Assoc;
+   |         --
 
 warning: bounds on generic parameters are not enforced in type aliases
   --> $DIR/type-alias-bounds.rs:57:12
@@ -79,5 +103,8 @@ warning: bounds on generic parameters are not enforced in type aliases
 LL | type T6<U: Bound> = ::std::vec::Vec<U>;
    |            ^^^^^
    |
-   = help: the bound will not be checked when the type alias is used, and should be removed
+help: the bound will not be checked when the type alias is used, and should be removed
+   |
+LL | type T6<U> = ::std::vec::Vec<U>;
+   |         --
 

From 08ca2360c4e817acab717dfb7e5a93d5af35cc06 Mon Sep 17 00:00:00 2001
From: jack-t <jackmaverick1@gmail.com>
Date: Fri, 4 Oct 2019 01:56:57 -0400
Subject: [PATCH 03/10] Add lint for unnecessary parens around types

---
 .../nice_region_error/find_anon_type.rs       |  2 +-
 .../owning_ref/mod.rs                         |  8 ++---
 src/librustc_lint/unused.rs                   | 19 ++++++++++++
 src/librustc_mir/borrow_check/prefixes.rs     |  2 +-
 src/libstd/collections/hash/map.rs            |  6 ++--
 src/test/ui/alignment-gep-tup-like-1.rs       |  2 +-
 src/test/ui/as-precedence.rs                  |  1 +
 src/test/ui/close-over-big-then-small-data.rs |  2 +-
 .../closure-to-fn-coercion.rs                 |  2 +-
 src/test/ui/lint/lint-unnecessary-parens.rs   | 12 ++++++++
 .../ui/lint/lint-unnecessary-parens.stderr    | 30 +++++++++++--------
 .../single-use-lifetime/zero-uses-in-fn.fixed |  2 +-
 .../ui/single-use-lifetime/zero-uses-in-fn.rs |  2 +-
 .../zero-uses-in-fn.stderr                    |  2 +-
 14 files changed, 65 insertions(+), 27 deletions(-)

diff --git a/src/librustc/infer/error_reporting/nice_region_error/find_anon_type.rs b/src/librustc/infer/error_reporting/nice_region_error/find_anon_type.rs
index 9c362a5e20791..f4751e591bf3c 100644
--- a/src/librustc/infer/error_reporting/nice_region_error/find_anon_type.rs
+++ b/src/librustc/infer/error_reporting/nice_region_error/find_anon_type.rs
@@ -62,7 +62,7 @@ impl<'a, 'tcx> NiceRegionError<'a, 'tcx> {
         &self,
         arg: &'tcx hir::Ty,
         br: &ty::BoundRegion,
-    ) -> Option<(&'tcx hir::Ty)> {
+    ) -> Option<&'tcx hir::Ty> {
         let mut nested_visitor = FindNestedTypeVisitor {
             tcx: self.tcx(),
             bound_region: *br,
diff --git a/src/librustc_data_structures/owning_ref/mod.rs b/src/librustc_data_structures/owning_ref/mod.rs
index b835b1706b85f..0213eb4f2a2a4 100644
--- a/src/librustc_data_structures/owning_ref/mod.rs
+++ b/src/librustc_data_structures/owning_ref/mod.rs
@@ -1046,14 +1046,14 @@ unsafe impl<O, T: ?Sized> CloneStableAddress for OwningRef<O, T>
     where O: CloneStableAddress {}
 
 unsafe impl<O, T: ?Sized> Send for OwningRef<O, T>
-    where O: Send, for<'a> (&'a T): Send {}
+    where O: Send, for<'a> &'a T: Send {}
 unsafe impl<O, T: ?Sized> Sync for OwningRef<O, T>
-    where O: Sync, for<'a> (&'a T): Sync {}
+    where O: Sync, for<'a> &'a T: Sync {}
 
 unsafe impl<O, T: ?Sized> Send for OwningRefMut<O, T>
-    where O: Send, for<'a> (&'a mut T): Send {}
+    where O: Send, for<'a> &'a mut T: Send {}
 unsafe impl<O, T: ?Sized> Sync for OwningRefMut<O, T>
-    where O: Sync, for<'a> (&'a mut T): Sync {}
+    where O: Sync, for<'a> &'a mut T: Sync {}
 
 impl Debug for dyn Erased {
     fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
diff --git a/src/librustc_lint/unused.rs b/src/librustc_lint/unused.rs
index 3b3995832cb4c..7a168baacaf81 100644
--- a/src/librustc_lint/unused.rs
+++ b/src/librustc_lint/unused.rs
@@ -603,6 +603,25 @@ impl EarlyLintPass for UnusedParens {
     fn check_arm(&mut self, cx: &EarlyContext<'_>, arm: &ast::Arm) {
         self.check_unused_parens_pat(cx, &arm.pat, false, false);
     }
+
+    fn check_ty(&mut self, cx: &EarlyContext<'_>, ty: &ast::Ty) {
+        if let &ast::TyKind::Paren(ref r) = &ty.kind {
+            match &r.kind {
+                &ast::TyKind::TraitObject(..) => {}
+                &ast::TyKind::ImplTrait(_, ref bounds) if bounds.len() > 1 => {}
+                _ => {
+                    let pattern_text = if let Ok(snippet) = cx.sess().source_map()
+                        .span_to_snippet(ty.span) {
+                            snippet
+                        } else {
+                            pprust::ty_to_string(ty)
+                        };
+
+                    Self::remove_outer_parens(cx, ty.span, &pattern_text, "type", (false, false));
+                }
+            }
+        }
+    }
 }
 
 declare_lint! {
diff --git a/src/librustc_mir/borrow_check/prefixes.rs b/src/librustc_mir/borrow_check/prefixes.rs
index a46a1cc5647a9..1be1fcef61b6e 100644
--- a/src/librustc_mir/borrow_check/prefixes.rs
+++ b/src/librustc_mir/borrow_check/prefixes.rs
@@ -29,7 +29,7 @@ pub(super) struct Prefixes<'cx, 'tcx> {
     body: &'cx Body<'tcx>,
     tcx: TyCtxt<'tcx>,
     kind: PrefixSet,
-    next: Option<(PlaceRef<'cx, 'tcx>)>,
+    next: Option<PlaceRef<'cx, 'tcx>>,
 }
 
 #[derive(Copy, Clone, PartialEq, Eq, Debug)]
diff --git a/src/libstd/collections/hash/map.rs b/src/libstd/collections/hash/map.rs
index ff50051ef5040..941c81eaff264 100644
--- a/src/libstd/collections/hash/map.rs
+++ b/src/libstd/collections/hash/map.rs
@@ -1818,7 +1818,7 @@ impl<'a, K, V> Iterator for Keys<'a, K, V> {
     type Item = &'a K;
 
     #[inline]
-    fn next(&mut self) -> Option<(&'a K)> {
+    fn next(&mut self) -> Option<&'a K> {
         self.inner.next().map(|(k, _)| k)
     }
     #[inline]
@@ -1841,7 +1841,7 @@ impl<'a, K, V> Iterator for Values<'a, K, V> {
     type Item = &'a V;
 
     #[inline]
-    fn next(&mut self) -> Option<(&'a V)> {
+    fn next(&mut self) -> Option<&'a V> {
         self.inner.next().map(|(_, v)| v)
     }
     #[inline]
@@ -1864,7 +1864,7 @@ impl<'a, K, V> Iterator for ValuesMut<'a, K, V> {
     type Item = &'a mut V;
 
     #[inline]
-    fn next(&mut self) -> Option<(&'a mut V)> {
+    fn next(&mut self) -> Option<&'a mut V> {
         self.inner.next().map(|(_, v)| v)
     }
     #[inline]
diff --git a/src/test/ui/alignment-gep-tup-like-1.rs b/src/test/ui/alignment-gep-tup-like-1.rs
index c51c56b089926..adbd05ed8c175 100644
--- a/src/test/ui/alignment-gep-tup-like-1.rs
+++ b/src/test/ui/alignment-gep-tup-like-1.rs
@@ -28,7 +28,7 @@ fn f<A:Clone + 'static>(a: A, b: u16) -> Box<dyn Invokable<A>+'static> {
     box Invoker {
         a: a,
         b: b,
-    } as (Box<dyn Invokable<A>+'static>)
+    } as Box<dyn Invokable<A>+'static>
 }
 
 pub fn main() {
diff --git a/src/test/ui/as-precedence.rs b/src/test/ui/as-precedence.rs
index a9f6fceb08ff0..feb0cb30ccacc 100644
--- a/src/test/ui/as-precedence.rs
+++ b/src/test/ui/as-precedence.rs
@@ -1,5 +1,6 @@
 // run-pass
 
+#[allow(unused_parens)]
 fn main() {
     assert_eq!(3 as usize * 3, 9);
     assert_eq!(3 as (usize) * 3, 9);
diff --git a/src/test/ui/close-over-big-then-small-data.rs b/src/test/ui/close-over-big-then-small-data.rs
index 40e5f500df4a8..4d6edf4ecb0f3 100644
--- a/src/test/ui/close-over-big-then-small-data.rs
+++ b/src/test/ui/close-over-big-then-small-data.rs
@@ -30,7 +30,7 @@ fn f<A:Clone + 'static>(a: A, b: u16) -> Box<dyn Invokable<A>+'static> {
     box Invoker {
         a: a,
         b: b,
-    } as (Box<dyn Invokable<A>+'static>)
+    } as Box<dyn Invokable<A>+'static>
 }
 
 pub fn main() {
diff --git a/src/test/ui/functions-closures/closure-to-fn-coercion.rs b/src/test/ui/functions-closures/closure-to-fn-coercion.rs
index 4f43c2bb53847..87ba488b5aef2 100644
--- a/src/test/ui/functions-closures/closure-to-fn-coercion.rs
+++ b/src/test/ui/functions-closures/closure-to-fn-coercion.rs
@@ -10,7 +10,7 @@ const BAR: [fn(&mut u32); 5] = [
     |v: &mut u32| *v += 3,
     |v: &mut u32| *v += 4,
 ];
-fn func_specific() -> (fn() -> u32) {
+fn func_specific() -> fn() -> u32 {
     || return 42
 }
 
diff --git a/src/test/ui/lint/lint-unnecessary-parens.rs b/src/test/ui/lint/lint-unnecessary-parens.rs
index 811bc87eb0e2e..9f42b855a870d 100644
--- a/src/test/ui/lint/lint-unnecessary-parens.rs
+++ b/src/test/ui/lint/lint-unnecessary-parens.rs
@@ -13,6 +13,18 @@ fn bar(y: bool) -> X {
     return (X { y }); //~ ERROR unnecessary parentheses around `return` value
 }
 
+fn unused_parens_around_return_type() -> (u32) { //~ ERROR unnecessary parentheses around type
+    panic!()
+}
+
+trait Trait {
+    fn test(&self);
+}
+
+fn passes_unused_parens_lint() -> &'static (dyn Trait) {
+    panic!()
+}
+
 fn main() {
     foo();
     bar((true)); //~ ERROR unnecessary parentheses around function argument
diff --git a/src/test/ui/lint/lint-unnecessary-parens.stderr b/src/test/ui/lint/lint-unnecessary-parens.stderr
index 83b247a4a6053..adc1069b64d62 100644
--- a/src/test/ui/lint/lint-unnecessary-parens.stderr
+++ b/src/test/ui/lint/lint-unnecessary-parens.stderr
@@ -16,26 +16,32 @@ error: unnecessary parentheses around `return` value
 LL |     return (X { y });
    |            ^^^^^^^^^ help: remove these parentheses
 
+error: unnecessary parentheses around type
+  --> $DIR/lint-unnecessary-parens.rs:16:42
+   |
+LL | fn unused_parens_around_return_type() -> (u32) {
+   |                                          ^^^^^ help: remove these parentheses
+
 error: unnecessary parentheses around function argument
-  --> $DIR/lint-unnecessary-parens.rs:18:9
+  --> $DIR/lint-unnecessary-parens.rs:30:9
    |
 LL |     bar((true));
    |         ^^^^^^ help: remove these parentheses
 
 error: unnecessary parentheses around `if` condition
-  --> $DIR/lint-unnecessary-parens.rs:20:8
+  --> $DIR/lint-unnecessary-parens.rs:32:8
    |
 LL |     if (true) {}
    |        ^^^^^^ help: remove these parentheses
 
 error: unnecessary parentheses around `while` condition
-  --> $DIR/lint-unnecessary-parens.rs:21:11
+  --> $DIR/lint-unnecessary-parens.rs:33:11
    |
 LL |     while (true) {}
    |           ^^^^^^ help: remove these parentheses
 
 warning: denote infinite loops with `loop { ... }`
-  --> $DIR/lint-unnecessary-parens.rs:21:5
+  --> $DIR/lint-unnecessary-parens.rs:33:5
    |
 LL |     while (true) {}
    |     ^^^^^^^^^^^^ help: use `loop`
@@ -43,46 +49,46 @@ LL |     while (true) {}
    = note: `#[warn(while_true)]` on by default
 
 error: unnecessary parentheses around `match` head expression
-  --> $DIR/lint-unnecessary-parens.rs:23:11
+  --> $DIR/lint-unnecessary-parens.rs:35:11
    |
 LL |     match (true) {
    |           ^^^^^^ help: remove these parentheses
 
 error: unnecessary parentheses around `let` head expression
-  --> $DIR/lint-unnecessary-parens.rs:26:16
+  --> $DIR/lint-unnecessary-parens.rs:38:16
    |
 LL |     if let 1 = (1) {}
    |                ^^^ help: remove these parentheses
 
 error: unnecessary parentheses around `let` head expression
-  --> $DIR/lint-unnecessary-parens.rs:27:19
+  --> $DIR/lint-unnecessary-parens.rs:39:19
    |
 LL |     while let 1 = (2) {}
    |                   ^^^ help: remove these parentheses
 
 error: unnecessary parentheses around method argument
-  --> $DIR/lint-unnecessary-parens.rs:41:24
+  --> $DIR/lint-unnecessary-parens.rs:53:24
    |
 LL |     X { y: false }.foo((true));
    |                        ^^^^^^ help: remove these parentheses
 
 error: unnecessary parentheses around assigned value
-  --> $DIR/lint-unnecessary-parens.rs:43:18
+  --> $DIR/lint-unnecessary-parens.rs:55:18
    |
 LL |     let mut _a = (0);
    |                  ^^^ help: remove these parentheses
 
 error: unnecessary parentheses around assigned value
-  --> $DIR/lint-unnecessary-parens.rs:44:10
+  --> $DIR/lint-unnecessary-parens.rs:56:10
    |
 LL |     _a = (0);
    |          ^^^ help: remove these parentheses
 
 error: unnecessary parentheses around assigned value
-  --> $DIR/lint-unnecessary-parens.rs:45:11
+  --> $DIR/lint-unnecessary-parens.rs:57:11
    |
 LL |     _a += (1);
    |           ^^^ help: remove these parentheses
 
-error: aborting due to 12 previous errors
+error: aborting due to 13 previous errors
 
diff --git a/src/test/ui/single-use-lifetime/zero-uses-in-fn.fixed b/src/test/ui/single-use-lifetime/zero-uses-in-fn.fixed
index 89607af260a52..0f26a975a370f 100644
--- a/src/test/ui/single-use-lifetime/zero-uses-in-fn.fixed
+++ b/src/test/ui/single-use-lifetime/zero-uses-in-fn.fixed
@@ -15,7 +15,7 @@ fn october<'b, T>(s: &'b T) -> &'b T {
     s
 }
 
-fn november<'a>(s: &'a str) -> (&'a str) {
+fn november<'a>(s: &'a str) -> &'a str {
     //~^ ERROR lifetime parameter `'b` never used
     //~| HELP elide the unused lifetime
     s
diff --git a/src/test/ui/single-use-lifetime/zero-uses-in-fn.rs b/src/test/ui/single-use-lifetime/zero-uses-in-fn.rs
index be0bdb9b62851..7f9504fe5a90a 100644
--- a/src/test/ui/single-use-lifetime/zero-uses-in-fn.rs
+++ b/src/test/ui/single-use-lifetime/zero-uses-in-fn.rs
@@ -15,7 +15,7 @@ fn october<'a, 'b, T>(s: &'b T) -> &'b T {
     s
 }
 
-fn november<'a, 'b>(s: &'a str) -> (&'a str) {
+fn november<'a, 'b>(s: &'a str) -> &'a str {
     //~^ ERROR lifetime parameter `'b` never used
     //~| HELP elide the unused lifetime
     s
diff --git a/src/test/ui/single-use-lifetime/zero-uses-in-fn.stderr b/src/test/ui/single-use-lifetime/zero-uses-in-fn.stderr
index 2ccba796d4229..b9c3bd89748ff 100644
--- a/src/test/ui/single-use-lifetime/zero-uses-in-fn.stderr
+++ b/src/test/ui/single-use-lifetime/zero-uses-in-fn.stderr
@@ -21,7 +21,7 @@ LL | fn october<'a, 'b, T>(s: &'b T) -> &'b T {
 error: lifetime parameter `'b` never used
   --> $DIR/zero-uses-in-fn.rs:18:17
    |
-LL | fn november<'a, 'b>(s: &'a str) -> (&'a str) {
+LL | fn november<'a, 'b>(s: &'a str) -> &'a str {
    |               --^^
    |               |
    |               help: elide the unused lifetime

From 1a8677ae1aa9202a3529078d87073fe052eb3ec6 Mon Sep 17 00:00:00 2001
From: Edd Barrett <vext01@gmail.com>
Date: Wed, 30 Oct 2019 10:03:41 +0000
Subject: [PATCH 04/10] Fix an incorrect docstring for Immediate in
 librustc_mir/interpret.

---
 src/librustc_mir/interpret/operand.rs | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/src/librustc_mir/interpret/operand.rs b/src/librustc_mir/interpret/operand.rs
index 4fd5e6a543551..ae23971849eea 100644
--- a/src/librustc_mir/interpret/operand.rs
+++ b/src/librustc_mir/interpret/operand.rs
@@ -19,7 +19,7 @@ use super::{
 };
 pub use rustc::mir::interpret::ScalarMaybeUndef;
 
-/// A `Value` represents a single immediate self-contained Rust value.
+/// An `Immediate` represents a single immediate self-contained Rust value.
 ///
 /// For optimization of a few very common cases, there is also a representation for a pair of
 /// primitive values (`ScalarPair`). It allows Miri to avoid making allocations for checked binary

From 39c5b0774ccaf05f10128e1c9e482bbc2cf0eec7 Mon Sep 17 00:00:00 2001
From: Mazdak Farrokhzad <twingoow@gmail.com>
Date: Sun, 27 Oct 2019 23:14:35 +0100
Subject: [PATCH 05/10] parser: don't hardcode ABIs into grammar

---
 src/librustc/error_codes.rs                   |   1 +
 src/librustc/hir/lowering.rs                  |   2 +-
 src/librustc/hir/lowering/item.rs             |  25 +-
 src/librustc_save_analysis/sig.rs             |  26 +-
 src/libsyntax/ast.rs                          |  24 +-
 src/libsyntax/error_codes.rs                  |   1 -
 src/libsyntax/feature_gate/check.rs           |  63 ++--
 src/libsyntax/parse/parser.rs                 |  38 +--
 src/libsyntax/parse/parser/item.rs            |  21 +-
 src/libsyntax/print/pprust.rs                 |  13 +-
 src/libsyntax/print/pprust/tests.rs           |   7 +-
 src/libsyntax_ext/deriving/generic/mod.rs     |  31 +-
 src/libsyntax_pos/symbol.rs                   |   1 +
 .../feature-gated-feature-in-macro-arg.stderr |   8 +-
 .../feature-gate-abi-msp430-interrupt.stderr  |   4 +-
 .../ui/feature-gates/feature-gate-abi.stderr  | 272 +++++++++---------
 .../feature-gate-abi_unadjusted.stderr        |   8 +-
 .../feature-gate-intrinsics.stderr            |  12 +-
 ...-gate-unboxed-closures-manual-impls.stderr |  16 +-
 .../feature-gate-unboxed-closures.stderr      |   8 +-
 20 files changed, 296 insertions(+), 285 deletions(-)

diff --git a/src/librustc/error_codes.rs b/src/librustc/error_codes.rs
index 3e35add9616bd..cb630780735a0 100644
--- a/src/librustc/error_codes.rs
+++ b/src/librustc/error_codes.rs
@@ -2336,6 +2336,7 @@ the future, [RFC 2091] prohibits their implementation without a follow-up RFC.
     E0657, // `impl Trait` can only capture lifetimes bound at the fn level
     E0687, // in-band lifetimes cannot be used in `fn`/`Fn` syntax
     E0688, // in-band lifetimes cannot be mixed with explicit lifetime binders
+    E0703, // invalid ABI
 //  E0707, // multiple elided lifetimes used in arguments of `async fn`
     E0708, // `async` non-`move` closures with parameters are not currently
            // supported
diff --git a/src/librustc/hir/lowering.rs b/src/librustc/hir/lowering.rs
index 12ab44515c38d..f8be1fe0d31bc 100644
--- a/src/librustc/hir/lowering.rs
+++ b/src/librustc/hir/lowering.rs
@@ -1210,7 +1210,7 @@ impl<'a> LoweringContext<'a> {
                                     ImplTraitContext::disallowed(),
                                 ),
                                 unsafety: this.lower_unsafety(f.unsafety),
-                                abi: f.abi,
+                                abi: this.lower_abi(f.abi),
                                 decl: this.lower_fn_decl(&f.decl, None, false, None),
                                 param_names: this.lower_fn_params_to_names(&f.decl),
                             }))
diff --git a/src/librustc/hir/lowering/item.rs b/src/librustc/hir/lowering/item.rs
index 9da87090c79bb..a8928eb506364 100644
--- a/src/librustc/hir/lowering/item.rs
+++ b/src/librustc/hir/lowering/item.rs
@@ -12,6 +12,7 @@ use crate::hir::def::{Res, DefKind};
 use crate::util::nodemap::NodeMap;
 
 use rustc_data_structures::thin_vec::ThinVec;
+use rustc_target::spec::abi;
 
 use std::collections::BTreeSet;
 use smallvec::SmallVec;
@@ -742,7 +743,7 @@ impl LoweringContext<'_> {
 
     fn lower_foreign_mod(&mut self, fm: &ForeignMod) -> hir::ForeignMod {
         hir::ForeignMod {
-            abi: fm.abi,
+            abi: self.lower_abi(fm.abi),
             items: fm.items
                 .iter()
                 .map(|x| self.lower_foreign_item(x))
@@ -1298,10 +1299,30 @@ impl LoweringContext<'_> {
             unsafety: self.lower_unsafety(h.unsafety),
             asyncness: self.lower_asyncness(h.asyncness.node),
             constness: self.lower_constness(h.constness),
-            abi: h.abi,
+            abi: self.lower_abi(h.abi),
         }
     }
 
+    pub(super) fn lower_abi(&mut self, abi: Abi) -> abi::Abi {
+        abi::lookup(&abi.symbol.as_str()).unwrap_or_else(|| {
+            self.error_on_invalid_abi(abi);
+            abi::Abi::Rust
+        })
+    }
+
+    fn error_on_invalid_abi(&self, abi: Abi) {
+        struct_span_err!(
+            self.sess,
+            abi.span,
+            E0703,
+            "invalid ABI: found `{}`",
+            abi.symbol
+        )
+        .span_label(abi.span, "invalid ABI")
+        .help(&format!("valid ABIs: {}", abi::all_names().join(", ")))
+        .emit();
+    }
+
     pub(super) fn lower_unsafety(&mut self, u: Unsafety) -> hir::Unsafety {
         match u {
             Unsafety::Unsafe => hir::Unsafety::Unsafe,
diff --git a/src/librustc_save_analysis/sig.rs b/src/librustc_save_analysis/sig.rs
index 203bd4d4167e2..019e92717b5d6 100644
--- a/src/librustc_save_analysis/sig.rs
+++ b/src/librustc_save_analysis/sig.rs
@@ -32,7 +32,7 @@ use rls_data::{SigElement, Signature};
 use rustc::hir::def::{Res, DefKind};
 use syntax::ast::{self, NodeId};
 use syntax::print::pprust;
-
+use syntax_pos::sym;
 
 pub fn item_signature(item: &ast::Item, scx: &SaveContext<'_, '_>) -> Option<Signature> {
     if !scx.config.signatures {
@@ -157,6 +157,12 @@ fn text_sig(text: String) -> Signature {
     }
 }
 
+fn push_abi(text: &mut String, abi: ast::Abi) {
+    if abi.symbol != sym::Rust {
+        text.push_str(&format!("extern \"{}\" ", abi.symbol));
+    }
+}
+
 impl Sig for ast::Ty {
     fn make(&self, offset: usize, _parent_id: Option<NodeId>, scx: &SaveContext<'_, '_>) -> Result {
         let id = Some(self.id);
@@ -231,11 +237,7 @@ impl Sig for ast::Ty {
                 if f.unsafety == ast::Unsafety::Unsafe {
                     text.push_str("unsafe ");
                 }
-                if f.abi != rustc_target::spec::abi::Abi::Rust {
-                    text.push_str("extern");
-                    text.push_str(&f.abi.to_string());
-                    text.push(' ');
-                }
+                push_abi(&mut text, f.abi);
                 text.push_str("fn(");
 
                 let mut defs = vec![];
@@ -385,11 +387,7 @@ impl Sig for ast::Item {
                 if header.unsafety == ast::Unsafety::Unsafe {
                     text.push_str("unsafe ");
                 }
-                if header.abi != rustc_target::spec::abi::Abi::Rust {
-                    text.push_str("extern");
-                    text.push_str(&header.abi.to_string());
-                    text.push(' ');
-                }
+                push_abi(&mut text, header.abi);
                 text.push_str("fn ");
 
                 let mut sig = name_and_generics(text, offset, generics, self.id, self.ident, scx)?;
@@ -948,11 +946,7 @@ fn make_method_signature(
     if m.header.unsafety == ast::Unsafety::Unsafe {
         text.push_str("unsafe ");
     }
-    if m.header.abi != rustc_target::spec::abi::Abi::Rust {
-        text.push_str("extern");
-        text.push_str(&m.header.abi.to_string());
-        text.push(' ');
-    }
+    push_abi(&mut text, m.header.abi);
     text.push_str("fn ");
 
     let mut sig = name_and_generics(text, 0, generics, id, ident, scx)?;
diff --git a/src/libsyntax/ast.rs b/src/libsyntax/ast.rs
index 8b96704884851..8ad1d859f3d04 100644
--- a/src/libsyntax/ast.rs
+++ b/src/libsyntax/ast.rs
@@ -38,7 +38,6 @@ use rustc_data_structures::sync::Lrc;
 use rustc_data_structures::thin_vec::ThinVec;
 use rustc_index::vec::Idx;
 use rustc_serialize::{self, Decoder, Encoder};
-use rustc_target::spec::abi::Abi;
 
 #[cfg(target_arch = "x86_64")]
 use rustc_data_structures::static_assert_size;
@@ -2351,6 +2350,27 @@ impl Item {
     }
 }
 
+/// A reference to an ABI.
+///
+/// In AST our notion of an ABI is still syntactic unlike in `rustc_target::spec::abi::Abi`.
+#[derive(Clone, Copy, RustcEncodable, RustcDecodable, Debug, PartialEq)]
+pub struct Abi {
+    pub symbol: Symbol,
+    pub span: Span,
+}
+
+impl Abi {
+    pub fn new(symbol: Symbol, span: Span) -> Self {
+        Self { symbol, span }
+    }
+}
+
+impl Default for Abi {
+    fn default() -> Self {
+        Self::new(sym::Rust, DUMMY_SP)
+    }
+}
+
 /// A function header.
 ///
 /// All the information between the visibility and the name of the function is
@@ -2369,7 +2389,7 @@ impl Default for FnHeader {
             unsafety: Unsafety::Normal,
             asyncness: dummy_spanned(IsAsync::NotAsync),
             constness: dummy_spanned(Constness::NotConst),
-            abi: Abi::Rust,
+            abi: Abi::default(),
         }
     }
 }
diff --git a/src/libsyntax/error_codes.rs b/src/libsyntax/error_codes.rs
index 17ea476752064..e697441cd1ce6 100644
--- a/src/libsyntax/error_codes.rs
+++ b/src/libsyntax/error_codes.rs
@@ -527,6 +527,5 @@ features in the `-Z allow_features` flag.
     E0630,
     E0693, // incorrect `repr(align)` attribute format
 //  E0694, // an unknown tool name found in scoped attributes
-    E0703, // invalid ABI
     E0717, // rustc_promotable without stability attribute
 }
diff --git a/src/libsyntax/feature_gate/check.rs b/src/libsyntax/feature_gate/check.rs
index 97b99b9392f3f..cae5b065234c3 100644
--- a/src/libsyntax/feature_gate/check.rs
+++ b/src/libsyntax/feature_gate/check.rs
@@ -14,7 +14,6 @@ use crate::tokenstream::TokenTree;
 
 use errors::{Applicability, DiagnosticBuilder, Handler};
 use rustc_data_structures::fx::FxHashMap;
-use rustc_target::spec::abi::Abi;
 use syntax_pos::{Span, DUMMY_SP, MultiSpan};
 use log::debug;
 
@@ -185,62 +184,70 @@ macro_rules! gate_feature_post {
 }
 
 impl<'a> PostExpansionVisitor<'a> {
-    fn check_abi(&self, abi: Abi, span: Span) {
-        match abi {
-            Abi::RustIntrinsic => {
+    fn check_abi(&self, abi: ast::Abi) {
+        let ast::Abi { symbol, span } = abi;
+
+        match &*symbol.as_str() {
+            // Stable
+            "Rust" |
+            "C" |
+            "cdecl" |
+            "stdcall" |
+            "fastcall" |
+            "aapcs" |
+            "win64" |
+            "sysv64" |
+            "system" => {}
+            "rust-intrinsic" => {
                 gate_feature_post!(&self, intrinsics, span,
                                    "intrinsics are subject to change");
             },
-            Abi::PlatformIntrinsic => {
+            "platform-intrinsic" => {
                 gate_feature_post!(&self, platform_intrinsics, span,
                                    "platform intrinsics are experimental and possibly buggy");
             },
-            Abi::Vectorcall => {
+            "vectorcall" => {
                 gate_feature_post!(&self, abi_vectorcall, span,
                                    "vectorcall is experimental and subject to change");
             },
-            Abi::Thiscall => {
+            "thiscall" => {
                 gate_feature_post!(&self, abi_thiscall, span,
                                    "thiscall is experimental and subject to change");
             },
-            Abi::RustCall => {
+            "rust-call" => {
                 gate_feature_post!(&self, unboxed_closures, span,
                                    "rust-call ABI is subject to change");
             },
-            Abi::PtxKernel => {
+            "ptx-kernel" => {
                 gate_feature_post!(&self, abi_ptx, span,
                                    "PTX ABIs are experimental and subject to change");
             },
-            Abi::Unadjusted => {
+            "unadjusted" => {
                 gate_feature_post!(&self, abi_unadjusted, span,
                                    "unadjusted ABI is an implementation detail and perma-unstable");
             },
-            Abi::Msp430Interrupt => {
+            "msp430-interrupt" => {
                 gate_feature_post!(&self, abi_msp430_interrupt, span,
                                    "msp430-interrupt ABI is experimental and subject to change");
             },
-            Abi::X86Interrupt => {
+            "x86-interrupt" => {
                 gate_feature_post!(&self, abi_x86_interrupt, span,
                                    "x86-interrupt ABI is experimental and subject to change");
             },
-            Abi::AmdGpuKernel => {
+            "amdgpu-kernel" => {
                 gate_feature_post!(&self, abi_amdgpu_kernel, span,
                                    "amdgpu-kernel ABI is experimental and subject to change");
             },
-            Abi::EfiApi => {
+            "efiapi" => {
                 gate_feature_post!(&self, abi_efiapi, span,
                                    "efiapi ABI is experimental and subject to change");
             },
-            // Stable
-            Abi::Cdecl |
-            Abi::Stdcall |
-            Abi::Fastcall |
-            Abi::Aapcs |
-            Abi::Win64 |
-            Abi::SysV64 |
-            Abi::Rust |
-            Abi::C |
-            Abi::System => {}
+            abi => {
+                self.parse_sess.span_diagnostic.delay_span_bug(
+                    span,
+                    &format!("unrecognized ABI not caught in lowering: {}", abi),
+                )
+            }
         }
     }
 
@@ -365,7 +372,7 @@ impl<'a> Visitor<'a> for PostExpansionVisitor<'a> {
     fn visit_item(&mut self, i: &'a ast::Item) {
         match i.kind {
             ast::ItemKind::ForeignMod(ref foreign_module) => {
-                self.check_abi(foreign_module.abi, i.span);
+                self.check_abi(foreign_module.abi);
             }
 
             ast::ItemKind::Fn(..) => {
@@ -481,7 +488,7 @@ impl<'a> Visitor<'a> for PostExpansionVisitor<'a> {
     fn visit_ty(&mut self, ty: &'a ast::Ty) {
         match ty.kind {
             ast::TyKind::BareFn(ref bare_fn_ty) => {
-                self.check_abi(bare_fn_ty.abi, ty.span);
+                self.check_abi(bare_fn_ty.abi);
             }
             ast::TyKind::Never => {
                 gate_feature_post!(&self, never_type, ty.span,
@@ -531,7 +538,7 @@ impl<'a> Visitor<'a> for PostExpansionVisitor<'a> {
             // Stability of const fn methods are covered in
             // `visit_trait_item` and `visit_impl_item` below; this is
             // because default methods don't pass through this point.
-            self.check_abi(header.abi, span);
+            self.check_abi(header.abi);
         }
 
         if fn_decl.c_variadic() {
@@ -545,7 +552,7 @@ impl<'a> Visitor<'a> for PostExpansionVisitor<'a> {
         match ti.kind {
             ast::TraitItemKind::Method(ref sig, ref block) => {
                 if block.is_none() {
-                    self.check_abi(sig.header.abi, ti.span);
+                    self.check_abi(sig.header.abi);
                 }
                 if sig.decl.c_variadic() {
                     gate_feature_post!(&self, c_variadic, ti.span,
diff --git a/src/libsyntax/parse/parser.rs b/src/libsyntax/parse/parser.rs
index 6ead1ce811d49..cf58cf9f13a52 100644
--- a/src/libsyntax/parse/parser.rs
+++ b/src/libsyntax/parse/parser.rs
@@ -12,7 +12,7 @@ mod diagnostics;
 use diagnostics::Error;
 
 use crate::ast::{
-    self, DUMMY_NODE_ID, AttrStyle, Attribute, CrateSugar, Ident,
+    self, Abi, DUMMY_NODE_ID, AttrStyle, Attribute, CrateSugar, Ident,
     IsAsync, MacDelimiter, Mutability, StrStyle, Visibility, VisibilityKind, Unsafety,
 };
 use crate::parse::{PResult, Directory, DirectoryOwnership};
@@ -28,7 +28,6 @@ use crate::tokenstream::{self, DelimSpan, TokenTree, TokenStream, TreeAndJoint};
 use crate::ThinVec;
 
 use errors::{Applicability, DiagnosticId, FatalError};
-use rustc_target::spec::abi::{self, Abi};
 use syntax_pos::{Span, BytePos, DUMMY_SP, FileName};
 use log::debug;
 
@@ -1209,48 +1208,27 @@ impl<'a> Parser<'a> {
 
     /// Parses `extern` followed by an optional ABI string, or nothing.
     fn parse_extern_abi(&mut self) -> PResult<'a, Abi> {
-        if self.eat_keyword(kw::Extern) {
-            Ok(self.parse_opt_abi()?.unwrap_or(Abi::C))
+        Ok(if self.eat_keyword(kw::Extern) {
+            let ext_sp = self.prev_span;
+            self.parse_opt_abi()?.unwrap_or_else(|| Abi::new(sym::C, ext_sp))
         } else {
-            Ok(Abi::Rust)
-        }
+            Abi::default()
+        })
     }
 
-    /// Parses a string as an ABI spec on an extern type or module. Consumes
-    /// the `extern` keyword, if one is found.
+    /// Parses a string as an ABI spec on an extern type or module.
     fn parse_opt_abi(&mut self) -> PResult<'a, Option<Abi>> {
         match self.token.kind {
             token::Literal(token::Lit { kind: token::Str, symbol, suffix }) |
             token::Literal(token::Lit { kind: token::StrRaw(..), symbol, suffix }) => {
                 self.expect_no_suffix(self.token.span, "an ABI spec", suffix);
                 self.bump();
-                match abi::lookup(&symbol.as_str()) {
-                    Some(abi) => Ok(Some(abi)),
-                    None => {
-                        self.error_on_invalid_abi(symbol);
-                        Ok(None)
-                    }
-                }
+                Ok(Some(Abi::new(symbol, self.prev_span)))
             }
             _ => Ok(None),
         }
     }
 
-    /// Emit an error where `symbol` is an invalid ABI.
-    fn error_on_invalid_abi(&self, symbol: Symbol) {
-        let prev_span = self.prev_span;
-        struct_span_err!(
-            self.sess.span_diagnostic,
-            prev_span,
-            E0703,
-            "invalid ABI: found `{}`",
-            symbol
-        )
-        .span_label(prev_span, "invalid ABI")
-        .help(&format!("valid ABIs: {}", abi::all_names().join(", ")))
-        .emit();
-    }
-
     /// We are parsing `async fn`. If we are on Rust 2015, emit an error.
     fn ban_async_in_2015(&self, async_span: Span) {
         if async_span.rust_2015() {
diff --git a/src/libsyntax/parse/parser/item.rs b/src/libsyntax/parse/parser/item.rs
index fe12533619033..46b93ab236a7d 100644
--- a/src/libsyntax/parse/parser/item.rs
+++ b/src/libsyntax/parse/parser/item.rs
@@ -3,7 +3,7 @@ use super::diagnostics::{Error, dummy_arg};
 
 use crate::maybe_whole;
 use crate::ptr::P;
-use crate::ast::{self, DUMMY_NODE_ID, Ident, Attribute, AttrStyle, AnonConst, Item, ItemKind};
+use crate::ast::{self, Abi, DUMMY_NODE_ID, Ident, Attribute, AttrStyle, AnonConst, Item, ItemKind};
 use crate::ast::{ImplItem, ImplItemKind, TraitItem, TraitItemKind, UseTree, UseTreeKind};
 use crate::ast::{PathSegment, IsAuto, Constness, IsAsync, Unsafety, Defaultness};
 use crate::ast::{Visibility, VisibilityKind, Mutability, FnHeader, ForeignItem, ForeignItemKind};
@@ -17,7 +17,6 @@ use crate::ThinVec;
 
 use log::debug;
 use std::mem;
-use rustc_target::spec::abi::Abi;
 use errors::{Applicability, DiagnosticBuilder, DiagnosticId, StashKey};
 use syntax_pos::BytePos;
 
@@ -111,7 +110,7 @@ impl<'a> Parser<'a> {
                 return Ok(Some(self.parse_item_extern_crate(lo, vis, attrs)?));
             }
 
-            let opt_abi = self.parse_opt_abi()?;
+            let abi = self.parse_opt_abi()?.unwrap_or_else(|| Abi::new(sym::C, extern_sp));
 
             if self.eat_keyword(kw::Fn) {
                 // EXTERN FUNCTION ITEM
@@ -120,12 +119,12 @@ impl<'a> Parser<'a> {
                     unsafety: Unsafety::Normal,
                     asyncness: respan(fn_span, IsAsync::NotAsync),
                     constness: respan(fn_span, Constness::NotConst),
-                    abi: opt_abi.unwrap_or(Abi::C),
+                    abi,
                 };
                 return self.parse_item_fn(lo, vis, attrs, header);
             } else if self.check(&token::OpenDelim(token::Brace)) {
                 return Ok(Some(
-                    self.parse_item_foreign_mod(lo, opt_abi, vis, attrs, extern_sp)?,
+                    self.parse_item_foreign_mod(lo, abi, vis, attrs, extern_sp)?,
                 ));
             }
 
@@ -201,7 +200,7 @@ impl<'a> Parser<'a> {
                     unsafety,
                     asyncness,
                     constness: respan(fn_span, Constness::NotConst),
-                    abi: Abi::Rust,
+                    abi: Abi::new(sym::Rust, fn_span),
                 };
                 return self.parse_item_fn(lo, vis, attrs, header);
             }
@@ -238,7 +237,7 @@ impl<'a> Parser<'a> {
                 unsafety: Unsafety::Normal,
                 asyncness: respan(fn_span, IsAsync::NotAsync),
                 constness: respan(fn_span, Constness::NotConst),
-                abi: Abi::Rust,
+                abi: Abi::new(sym::Rust, fn_span),
             };
             return self.parse_item_fn(lo, vis, attrs, header);
         }
@@ -1111,15 +1110,13 @@ impl<'a> Parser<'a> {
     fn parse_item_foreign_mod(
         &mut self,
         lo: Span,
-        opt_abi: Option<Abi>,
+        abi: Abi,
         visibility: Visibility,
         mut attrs: Vec<Attribute>,
         extern_sp: Span,
     ) -> PResult<'a, P<Item>> {
         self.expect(&token::OpenDelim(token::Brace))?;
 
-        let abi = opt_abi.unwrap_or(Abi::C);
-
         attrs.extend(self.parse_inner_attributes()?);
 
         let mut foreign_items = vec![];
@@ -1796,7 +1793,7 @@ impl<'a> Parser<'a> {
     ) -> PResult<'a, Option<P<Item>>> {
         let (ident, decl, generics) = self.parse_fn_sig(ParamCfg {
             is_self_allowed: false,
-            allow_c_variadic: header.abi == Abi::C && header.unsafety == Unsafety::Unsafe,
+            allow_c_variadic: header.abi.symbol == sym::C && header.unsafety == Unsafety::Unsafe,
             is_name_required: |_| true,
         })?;
         let (inner_attrs, body) = self.parse_inner_attrs_and_block()?;
@@ -1925,7 +1922,7 @@ impl<'a> Parser<'a> {
         let asyncness = respan(self.prev_span, asyncness);
         let unsafety = self.parse_unsafety();
         let (constness, unsafety, abi) = if is_const_fn {
-            (respan(const_span, Constness::Const), unsafety, Abi::Rust)
+            (respan(const_span, Constness::Const), unsafety, Abi::default())
         } else {
             let abi = self.parse_extern_abi()?;
             (respan(self.prev_span, Constness::NotConst), unsafety, abi)
diff --git a/src/libsyntax/print/pprust.rs b/src/libsyntax/print/pprust.rs
index 136fc355f89d4..10fb391b85d38 100644
--- a/src/libsyntax/print/pprust.rs
+++ b/src/libsyntax/print/pprust.rs
@@ -14,7 +14,6 @@ use crate::sess::ParseSess;
 use crate::symbol::{kw, sym};
 use crate::tokenstream::{self, TokenStream, TokenTree};
 
-use rustc_target::spec::abi::{self, Abi};
 use syntax_pos::{self, BytePos};
 use syntax_pos::{FileName, Span};
 
@@ -1227,7 +1226,7 @@ impl<'a> State<'a> {
             }
             ast::ItemKind::ForeignMod(ref nmod) => {
                 self.head("extern");
-                self.word_nbsp(nmod.abi.to_string());
+                self.print_abi(nmod.abi);
                 self.bopen();
                 self.print_foreign_mod(nmod, &item.attrs);
                 self.bclose(item.span);
@@ -2820,7 +2819,7 @@ impl<'a> State<'a> {
     }
 
     crate fn print_ty_fn(&mut self,
-                       abi: abi::Abi,
+                       abi: ast::Abi,
                        unsafety: ast::Unsafety,
                        decl: &ast::FnDecl,
                        name: Option<ast::Ident>,
@@ -2881,14 +2880,18 @@ impl<'a> State<'a> {
         self.print_asyncness(header.asyncness.node);
         self.print_unsafety(header.unsafety);
 
-        if header.abi != Abi::Rust {
+        if header.abi.symbol != sym::Rust {
             self.word_nbsp("extern");
-            self.word_nbsp(header.abi.to_string());
+            self.print_abi(header.abi);
         }
 
         self.s.word("fn")
     }
 
+    fn print_abi(&mut self, abi: ast::Abi) {
+        self.word_nbsp(format!("\"{}\"", abi.symbol));
+    }
+
     crate fn print_unsafety(&mut self, s: ast::Unsafety) {
         match s {
             ast::Unsafety::Normal => {},
diff --git a/src/libsyntax/print/pprust/tests.rs b/src/libsyntax/print/pprust/tests.rs
index faa70edbfa29b..2c6dd0fb1c6dc 100644
--- a/src/libsyntax/print/pprust/tests.rs
+++ b/src/libsyntax/print/pprust/tests.rs
@@ -34,12 +34,7 @@ fn test_fun_to_string() {
         assert_eq!(
             fun_to_string(
                 &decl,
-                ast::FnHeader {
-                    unsafety: ast::Unsafety::Normal,
-                    constness: source_map::dummy_spanned(ast::Constness::NotConst),
-                    asyncness: source_map::dummy_spanned(ast::IsAsync::NotAsync),
-                    abi: Abi::Rust,
-                },
+                ast::FnHeader::default(),
                 abba_ident,
                 &generics
             ),
diff --git a/src/libsyntax_ext/deriving/generic/mod.rs b/src/libsyntax_ext/deriving/generic/mod.rs
index c04b65245e1f7..073de25819e86 100644
--- a/src/libsyntax_ext/deriving/generic/mod.rs
+++ b/src/libsyntax_ext/deriving/generic/mod.rs
@@ -182,8 +182,7 @@ use std::iter;
 use std::vec;
 
 use rustc_data_structures::thin_vec::ThinVec;
-use rustc_target::spec::abi::Abi;
-use syntax::ast::{self, BinOpKind, EnumDef, Expr, Generics, Ident, PatKind};
+use syntax::ast::{self, Abi, BinOpKind, EnumDef, Expr, Generics, Ident, PatKind};
 use syntax::ast::{VariantData, GenericParamKind, GenericArg};
 use syntax::attr;
 use syntax::expand::SpecialDerives;
@@ -741,7 +740,7 @@ impl<'a> TraitDef<'a> {
                                          self,
                                          type_ident,
                                          generics,
-                                         Abi::Rust,
+                                         sym::Rust,
                                          explicit_self,
                                          tys,
                                          body)
@@ -796,7 +795,7 @@ impl<'a> TraitDef<'a> {
                                          self,
                                          type_ident,
                                          generics,
-                                         Abi::Rust,
+                                         sym::Rust,
                                          explicit_self,
                                          tys,
                                          body)
@@ -922,7 +921,7 @@ impl<'a> MethodDef<'a> {
                      trait_: &TraitDef<'_>,
                      type_ident: Ident,
                      generics: &Generics,
-                     abi: Abi,
+                     abi: Symbol,
                      explicit_self: Option<ast::ExplicitSelf>,
                      arg_types: Vec<(Ident, P<ast::Ty>)>,
                      body: P<Expr>)
@@ -952,23 +951,27 @@ impl<'a> MethodDef<'a> {
             ast::Unsafety::Normal
         };
 
+        let trait_lo_sp = trait_.span.shrink_to_lo();
+
+        let sig = ast::MethodSig {
+            header: ast::FnHeader {
+                unsafety,
+                abi: Abi::new(abi, trait_lo_sp),
+                ..ast::FnHeader::default()
+            },
+            decl: fn_decl,
+        };
+
         // Create the method.
         ast::ImplItem {
             id: ast::DUMMY_NODE_ID,
             attrs: self.attributes.clone(),
             generics: fn_generics,
             span: trait_.span,
-            vis: respan(trait_.span.shrink_to_lo(), ast::VisibilityKind::Inherited),
+            vis: respan(trait_lo_sp, ast::VisibilityKind::Inherited),
             defaultness: ast::Defaultness::Final,
             ident: method_ident,
-            kind: ast::ImplItemKind::Method(ast::MethodSig {
-                                                header: ast::FnHeader {
-                                                    unsafety, abi,
-                                                    ..ast::FnHeader::default()
-                                                },
-                                                decl: fn_decl,
-                                            },
-                                            body_block),
+            kind: ast::ImplItemKind::Method(sig, body_block),
             tokens: None,
         }
     }
diff --git a/src/libsyntax_pos/symbol.rs b/src/libsyntax_pos/symbol.rs
index 8ba161f55c1ff..3ef4efa397cce 100644
--- a/src/libsyntax_pos/symbol.rs
+++ b/src/libsyntax_pos/symbol.rs
@@ -562,6 +562,7 @@ symbols! {
         rust_2018_preview,
         rust_begin_unwind,
         rustc,
+        Rust,
         RustcDecodable,
         RustcEncodable,
         rustc_allocator,
diff --git a/src/test/ui/feature-gated-feature-in-macro-arg.stderr b/src/test/ui/feature-gated-feature-in-macro-arg.stderr
index 5ee05154c3a2a..218e0292776d0 100644
--- a/src/test/ui/feature-gated-feature-in-macro-arg.stderr
+++ b/src/test/ui/feature-gated-feature-in-macro-arg.stderr
@@ -1,10 +1,8 @@
 error[E0658]: intrinsics are subject to change
-  --> $DIR/feature-gated-feature-in-macro-arg.rs:8:9
+  --> $DIR/feature-gated-feature-in-macro-arg.rs:8:16
    |
-LL | /         extern "rust-intrinsic" {
-LL | |             fn atomic_fence();
-LL | |         }
-   | |_________^
+LL |         extern "rust-intrinsic" {
+   |                ^^^^^^^^^^^^^^^^
    |
    = help: add `#![feature(intrinsics)]` to the crate attributes to enable
 
diff --git a/src/test/ui/feature-gates/feature-gate-abi-msp430-interrupt.stderr b/src/test/ui/feature-gates/feature-gate-abi-msp430-interrupt.stderr
index 0d2e355535dee..d58a2d91b2b7f 100644
--- a/src/test/ui/feature-gates/feature-gate-abi-msp430-interrupt.stderr
+++ b/src/test/ui/feature-gates/feature-gate-abi-msp430-interrupt.stderr
@@ -1,8 +1,8 @@
 error[E0658]: msp430-interrupt ABI is experimental and subject to change
-  --> $DIR/feature-gate-abi-msp430-interrupt.rs:4:1
+  --> $DIR/feature-gate-abi-msp430-interrupt.rs:4:8
    |
 LL | extern "msp430-interrupt" fn foo() {}
-   | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
+   |        ^^^^^^^^^^^^^^^^^^
    |
    = note: for more information, see https://github.com/rust-lang/rust/issues/38487
    = help: add `#![feature(abi_msp430_interrupt)]` to the crate attributes to enable
diff --git a/src/test/ui/feature-gates/feature-gate-abi.stderr b/src/test/ui/feature-gates/feature-gate-abi.stderr
index 0f2622f106595..6db6cb49cef14 100644
--- a/src/test/ui/feature-gates/feature-gate-abi.stderr
+++ b/src/test/ui/feature-gates/feature-gate-abi.stderr
@@ -1,591 +1,591 @@
 error[E0658]: intrinsics are subject to change
-  --> $DIR/feature-gate-abi.rs:13:1
+  --> $DIR/feature-gate-abi.rs:13:8
    |
 LL | extern "rust-intrinsic" fn f1() {}
-   | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
+   |        ^^^^^^^^^^^^^^^^
    |
    = help: add `#![feature(intrinsics)]` to the crate attributes to enable
 
 error[E0658]: platform intrinsics are experimental and possibly buggy
-  --> $DIR/feature-gate-abi.rs:15:1
+  --> $DIR/feature-gate-abi.rs:15:8
    |
 LL | extern "platform-intrinsic" fn f2() {}
-   | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
+   |        ^^^^^^^^^^^^^^^^^^^^
    |
    = note: for more information, see https://github.com/rust-lang/rust/issues/27731
    = help: add `#![feature(platform_intrinsics)]` to the crate attributes to enable
 
 error[E0658]: vectorcall is experimental and subject to change
-  --> $DIR/feature-gate-abi.rs:17:1
+  --> $DIR/feature-gate-abi.rs:17:8
    |
 LL | extern "vectorcall" fn f3() {}
-   | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
+   |        ^^^^^^^^^^^^
    |
    = help: add `#![feature(abi_vectorcall)]` to the crate attributes to enable
 
 error[E0658]: rust-call ABI is subject to change
-  --> $DIR/feature-gate-abi.rs:18:1
+  --> $DIR/feature-gate-abi.rs:18:8
    |
 LL | extern "rust-call" fn f4() {}
-   | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
+   |        ^^^^^^^^^^^
    |
    = note: for more information, see https://github.com/rust-lang/rust/issues/29625
    = help: add `#![feature(unboxed_closures)]` to the crate attributes to enable
 
 error[E0658]: msp430-interrupt ABI is experimental and subject to change
-  --> $DIR/feature-gate-abi.rs:19:1
+  --> $DIR/feature-gate-abi.rs:19:8
    |
 LL | extern "msp430-interrupt" fn f5() {}
-   | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
+   |        ^^^^^^^^^^^^^^^^^^
    |
    = note: for more information, see https://github.com/rust-lang/rust/issues/38487
    = help: add `#![feature(abi_msp430_interrupt)]` to the crate attributes to enable
 
 error[E0658]: PTX ABIs are experimental and subject to change
-  --> $DIR/feature-gate-abi.rs:20:1
+  --> $DIR/feature-gate-abi.rs:20:8
    |
 LL | extern "ptx-kernel" fn f6() {}
-   | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
+   |        ^^^^^^^^^^^^
    |
    = note: for more information, see https://github.com/rust-lang/rust/issues/38788
    = help: add `#![feature(abi_ptx)]` to the crate attributes to enable
 
 error[E0658]: x86-interrupt ABI is experimental and subject to change
-  --> $DIR/feature-gate-abi.rs:21:1
+  --> $DIR/feature-gate-abi.rs:21:8
    |
 LL | extern "x86-interrupt" fn f7() {}
-   | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
+   |        ^^^^^^^^^^^^^^^
    |
    = note: for more information, see https://github.com/rust-lang/rust/issues/40180
    = help: add `#![feature(abi_x86_interrupt)]` to the crate attributes to enable
 
 error[E0658]: thiscall is experimental and subject to change
-  --> $DIR/feature-gate-abi.rs:22:1
+  --> $DIR/feature-gate-abi.rs:22:8
    |
 LL | extern "thiscall" fn f8() {}
-   | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^
+   |        ^^^^^^^^^^
    |
    = help: add `#![feature(abi_thiscall)]` to the crate attributes to enable
 
 error[E0658]: amdgpu-kernel ABI is experimental and subject to change
-  --> $DIR/feature-gate-abi.rs:23:1
+  --> $DIR/feature-gate-abi.rs:23:8
    |
 LL | extern "amdgpu-kernel" fn f9() {}
-   | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
+   |        ^^^^^^^^^^^^^^^
    |
    = note: for more information, see https://github.com/rust-lang/rust/issues/51575
    = help: add `#![feature(abi_amdgpu_kernel)]` to the crate attributes to enable
 
 error[E0658]: efiapi ABI is experimental and subject to change
-  --> $DIR/feature-gate-abi.rs:24:1
+  --> $DIR/feature-gate-abi.rs:24:8
    |
 LL | extern "efiapi" fn f10() {}
-   | ^^^^^^^^^^^^^^^^^^^^^^^^^^^
+   |        ^^^^^^^^
    |
    = note: for more information, see https://github.com/rust-lang/rust/issues/65815
    = help: add `#![feature(abi_efiapi)]` to the crate attributes to enable
 
 error[E0658]: intrinsics are subject to change
-  --> $DIR/feature-gate-abi.rs:28:5
+  --> $DIR/feature-gate-abi.rs:28:12
    |
 LL |     extern "rust-intrinsic" fn m1();
-   |     ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
+   |            ^^^^^^^^^^^^^^^^
    |
    = help: add `#![feature(intrinsics)]` to the crate attributes to enable
 
 error[E0658]: platform intrinsics are experimental and possibly buggy
-  --> $DIR/feature-gate-abi.rs:30:5
+  --> $DIR/feature-gate-abi.rs:30:12
    |
 LL |     extern "platform-intrinsic" fn m2();
-   |     ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
+   |            ^^^^^^^^^^^^^^^^^^^^
    |
    = note: for more information, see https://github.com/rust-lang/rust/issues/27731
    = help: add `#![feature(platform_intrinsics)]` to the crate attributes to enable
 
 error[E0658]: vectorcall is experimental and subject to change
-  --> $DIR/feature-gate-abi.rs:32:5
+  --> $DIR/feature-gate-abi.rs:32:12
    |
 LL |     extern "vectorcall" fn m3();
-   |     ^^^^^^^^^^^^^^^^^^^^^^^^^^^^
+   |            ^^^^^^^^^^^^
    |
    = help: add `#![feature(abi_vectorcall)]` to the crate attributes to enable
 
 error[E0658]: rust-call ABI is subject to change
-  --> $DIR/feature-gate-abi.rs:33:5
+  --> $DIR/feature-gate-abi.rs:33:12
    |
 LL |     extern "rust-call" fn m4();
-   |     ^^^^^^^^^^^^^^^^^^^^^^^^^^^
+   |            ^^^^^^^^^^^
    |
    = note: for more information, see https://github.com/rust-lang/rust/issues/29625
    = help: add `#![feature(unboxed_closures)]` to the crate attributes to enable
 
 error[E0658]: msp430-interrupt ABI is experimental and subject to change
-  --> $DIR/feature-gate-abi.rs:34:5
+  --> $DIR/feature-gate-abi.rs:34:12
    |
 LL |     extern "msp430-interrupt" fn m5();
-   |     ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
+   |            ^^^^^^^^^^^^^^^^^^
    |
    = note: for more information, see https://github.com/rust-lang/rust/issues/38487
    = help: add `#![feature(abi_msp430_interrupt)]` to the crate attributes to enable
 
 error[E0658]: PTX ABIs are experimental and subject to change
-  --> $DIR/feature-gate-abi.rs:35:5
+  --> $DIR/feature-gate-abi.rs:35:12
    |
 LL |     extern "ptx-kernel" fn m6();
-   |     ^^^^^^^^^^^^^^^^^^^^^^^^^^^^
+   |            ^^^^^^^^^^^^
    |
    = note: for more information, see https://github.com/rust-lang/rust/issues/38788
    = help: add `#![feature(abi_ptx)]` to the crate attributes to enable
 
 error[E0658]: x86-interrupt ABI is experimental and subject to change
-  --> $DIR/feature-gate-abi.rs:36:5
+  --> $DIR/feature-gate-abi.rs:36:12
    |
 LL |     extern "x86-interrupt" fn m7();
-   |     ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
+   |            ^^^^^^^^^^^^^^^
    |
    = note: for more information, see https://github.com/rust-lang/rust/issues/40180
    = help: add `#![feature(abi_x86_interrupt)]` to the crate attributes to enable
 
 error[E0658]: thiscall is experimental and subject to change
-  --> $DIR/feature-gate-abi.rs:37:5
+  --> $DIR/feature-gate-abi.rs:37:12
    |
 LL |     extern "thiscall" fn m8();
-   |     ^^^^^^^^^^^^^^^^^^^^^^^^^^
+   |            ^^^^^^^^^^
    |
    = help: add `#![feature(abi_thiscall)]` to the crate attributes to enable
 
 error[E0658]: amdgpu-kernel ABI is experimental and subject to change
-  --> $DIR/feature-gate-abi.rs:38:5
+  --> $DIR/feature-gate-abi.rs:38:12
    |
 LL |     extern "amdgpu-kernel" fn m9();
-   |     ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
+   |            ^^^^^^^^^^^^^^^
    |
    = note: for more information, see https://github.com/rust-lang/rust/issues/51575
    = help: add `#![feature(abi_amdgpu_kernel)]` to the crate attributes to enable
 
 error[E0658]: efiapi ABI is experimental and subject to change
-  --> $DIR/feature-gate-abi.rs:39:5
+  --> $DIR/feature-gate-abi.rs:39:12
    |
 LL |     extern "efiapi" fn m10();
-   |     ^^^^^^^^^^^^^^^^^^^^^^^^^
+   |            ^^^^^^^^
    |
    = note: for more information, see https://github.com/rust-lang/rust/issues/65815
    = help: add `#![feature(abi_efiapi)]` to the crate attributes to enable
 
 error[E0658]: vectorcall is experimental and subject to change
-  --> $DIR/feature-gate-abi.rs:41:5
+  --> $DIR/feature-gate-abi.rs:41:12
    |
 LL |     extern "vectorcall" fn dm3() {}
-   |     ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
+   |            ^^^^^^^^^^^^
    |
    = help: add `#![feature(abi_vectorcall)]` to the crate attributes to enable
 
 error[E0658]: rust-call ABI is subject to change
-  --> $DIR/feature-gate-abi.rs:42:5
+  --> $DIR/feature-gate-abi.rs:42:12
    |
 LL |     extern "rust-call" fn dm4() {}
-   |     ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
+   |            ^^^^^^^^^^^
    |
    = note: for more information, see https://github.com/rust-lang/rust/issues/29625
    = help: add `#![feature(unboxed_closures)]` to the crate attributes to enable
 
 error[E0658]: msp430-interrupt ABI is experimental and subject to change
-  --> $DIR/feature-gate-abi.rs:43:5
+  --> $DIR/feature-gate-abi.rs:43:12
    |
 LL |     extern "msp430-interrupt" fn dm5() {}
-   |     ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
+   |            ^^^^^^^^^^^^^^^^^^
    |
    = note: for more information, see https://github.com/rust-lang/rust/issues/38487
    = help: add `#![feature(abi_msp430_interrupt)]` to the crate attributes to enable
 
 error[E0658]: PTX ABIs are experimental and subject to change
-  --> $DIR/feature-gate-abi.rs:44:5
+  --> $DIR/feature-gate-abi.rs:44:12
    |
 LL |     extern "ptx-kernel" fn dm6() {}
-   |     ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
+   |            ^^^^^^^^^^^^
    |
    = note: for more information, see https://github.com/rust-lang/rust/issues/38788
    = help: add `#![feature(abi_ptx)]` to the crate attributes to enable
 
 error[E0658]: x86-interrupt ABI is experimental and subject to change
-  --> $DIR/feature-gate-abi.rs:45:5
+  --> $DIR/feature-gate-abi.rs:45:12
    |
 LL |     extern "x86-interrupt" fn dm7() {}
-   |     ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
+   |            ^^^^^^^^^^^^^^^
    |
    = note: for more information, see https://github.com/rust-lang/rust/issues/40180
    = help: add `#![feature(abi_x86_interrupt)]` to the crate attributes to enable
 
 error[E0658]: thiscall is experimental and subject to change
-  --> $DIR/feature-gate-abi.rs:46:5
+  --> $DIR/feature-gate-abi.rs:46:12
    |
 LL |     extern "thiscall" fn dm8() {}
-   |     ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
+   |            ^^^^^^^^^^
    |
    = help: add `#![feature(abi_thiscall)]` to the crate attributes to enable
 
 error[E0658]: amdgpu-kernel ABI is experimental and subject to change
-  --> $DIR/feature-gate-abi.rs:47:5
+  --> $DIR/feature-gate-abi.rs:47:12
    |
 LL |     extern "amdgpu-kernel" fn dm9() {}
-   |     ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
+   |            ^^^^^^^^^^^^^^^
    |
    = note: for more information, see https://github.com/rust-lang/rust/issues/51575
    = help: add `#![feature(abi_amdgpu_kernel)]` to the crate attributes to enable
 
 error[E0658]: efiapi ABI is experimental and subject to change
-  --> $DIR/feature-gate-abi.rs:48:5
+  --> $DIR/feature-gate-abi.rs:48:12
    |
 LL |     extern "efiapi" fn dm10() {}
-   |     ^^^^^^^^^^^^^^^^^^^^^^^^^^^^
+   |            ^^^^^^^^
    |
    = note: for more information, see https://github.com/rust-lang/rust/issues/65815
    = help: add `#![feature(abi_efiapi)]` to the crate attributes to enable
 
 error[E0658]: intrinsics are subject to change
-  --> $DIR/feature-gate-abi.rs:55:5
+  --> $DIR/feature-gate-abi.rs:55:12
    |
 LL |     extern "rust-intrinsic" fn m1() {}
-   |     ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
+   |            ^^^^^^^^^^^^^^^^
    |
    = help: add `#![feature(intrinsics)]` to the crate attributes to enable
 
 error[E0658]: platform intrinsics are experimental and possibly buggy
-  --> $DIR/feature-gate-abi.rs:57:5
+  --> $DIR/feature-gate-abi.rs:57:12
    |
 LL |     extern "platform-intrinsic" fn m2() {}
-   |     ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
+   |            ^^^^^^^^^^^^^^^^^^^^
    |
    = note: for more information, see https://github.com/rust-lang/rust/issues/27731
    = help: add `#![feature(platform_intrinsics)]` to the crate attributes to enable
 
 error[E0658]: vectorcall is experimental and subject to change
-  --> $DIR/feature-gate-abi.rs:59:5
+  --> $DIR/feature-gate-abi.rs:59:12
    |
 LL |     extern "vectorcall" fn m3() {}
-   |     ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
+   |            ^^^^^^^^^^^^
    |
    = help: add `#![feature(abi_vectorcall)]` to the crate attributes to enable
 
 error[E0658]: rust-call ABI is subject to change
-  --> $DIR/feature-gate-abi.rs:60:5
+  --> $DIR/feature-gate-abi.rs:60:12
    |
 LL |     extern "rust-call" fn m4() {}
-   |     ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
+   |            ^^^^^^^^^^^
    |
    = note: for more information, see https://github.com/rust-lang/rust/issues/29625
    = help: add `#![feature(unboxed_closures)]` to the crate attributes to enable
 
 error[E0658]: msp430-interrupt ABI is experimental and subject to change
-  --> $DIR/feature-gate-abi.rs:61:5
+  --> $DIR/feature-gate-abi.rs:61:12
    |
 LL |     extern "msp430-interrupt" fn m5() {}
-   |     ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
+   |            ^^^^^^^^^^^^^^^^^^
    |
    = note: for more information, see https://github.com/rust-lang/rust/issues/38487
    = help: add `#![feature(abi_msp430_interrupt)]` to the crate attributes to enable
 
 error[E0658]: PTX ABIs are experimental and subject to change
-  --> $DIR/feature-gate-abi.rs:62:5
+  --> $DIR/feature-gate-abi.rs:62:12
    |
 LL |     extern "ptx-kernel" fn m6() {}
-   |     ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
+   |            ^^^^^^^^^^^^
    |
    = note: for more information, see https://github.com/rust-lang/rust/issues/38788
    = help: add `#![feature(abi_ptx)]` to the crate attributes to enable
 
 error[E0658]: x86-interrupt ABI is experimental and subject to change
-  --> $DIR/feature-gate-abi.rs:63:5
+  --> $DIR/feature-gate-abi.rs:63:12
    |
 LL |     extern "x86-interrupt" fn m7() {}
-   |     ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
+   |            ^^^^^^^^^^^^^^^
    |
    = note: for more information, see https://github.com/rust-lang/rust/issues/40180
    = help: add `#![feature(abi_x86_interrupt)]` to the crate attributes to enable
 
 error[E0658]: thiscall is experimental and subject to change
-  --> $DIR/feature-gate-abi.rs:64:5
+  --> $DIR/feature-gate-abi.rs:64:12
    |
 LL |     extern "thiscall" fn m8() {}
-   |     ^^^^^^^^^^^^^^^^^^^^^^^^^^^^
+   |            ^^^^^^^^^^
    |
    = help: add `#![feature(abi_thiscall)]` to the crate attributes to enable
 
 error[E0658]: amdgpu-kernel ABI is experimental and subject to change
-  --> $DIR/feature-gate-abi.rs:65:5
+  --> $DIR/feature-gate-abi.rs:65:12
    |
 LL |     extern "amdgpu-kernel" fn m9() {}
-   |     ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
+   |            ^^^^^^^^^^^^^^^
    |
    = note: for more information, see https://github.com/rust-lang/rust/issues/51575
    = help: add `#![feature(abi_amdgpu_kernel)]` to the crate attributes to enable
 
 error[E0658]: efiapi ABI is experimental and subject to change
-  --> $DIR/feature-gate-abi.rs:66:5
+  --> $DIR/feature-gate-abi.rs:66:12
    |
 LL |     extern "efiapi" fn m10() {}
-   |     ^^^^^^^^^^^^^^^^^^^^^^^^^^^
+   |            ^^^^^^^^
    |
    = note: for more information, see https://github.com/rust-lang/rust/issues/65815
    = help: add `#![feature(abi_efiapi)]` to the crate attributes to enable
 
 error[E0658]: intrinsics are subject to change
-  --> $DIR/feature-gate-abi.rs:71:5
+  --> $DIR/feature-gate-abi.rs:71:12
    |
 LL |     extern "rust-intrinsic" fn im1() {}
-   |     ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
+   |            ^^^^^^^^^^^^^^^^
    |
    = help: add `#![feature(intrinsics)]` to the crate attributes to enable
 
 error[E0658]: platform intrinsics are experimental and possibly buggy
-  --> $DIR/feature-gate-abi.rs:73:5
+  --> $DIR/feature-gate-abi.rs:73:12
    |
 LL |     extern "platform-intrinsic" fn im2() {}
-   |     ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
+   |            ^^^^^^^^^^^^^^^^^^^^
    |
    = note: for more information, see https://github.com/rust-lang/rust/issues/27731
    = help: add `#![feature(platform_intrinsics)]` to the crate attributes to enable
 
 error[E0658]: vectorcall is experimental and subject to change
-  --> $DIR/feature-gate-abi.rs:75:5
+  --> $DIR/feature-gate-abi.rs:75:12
    |
 LL |     extern "vectorcall" fn im3() {}
-   |     ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
+   |            ^^^^^^^^^^^^
    |
    = help: add `#![feature(abi_vectorcall)]` to the crate attributes to enable
 
 error[E0658]: rust-call ABI is subject to change
-  --> $DIR/feature-gate-abi.rs:76:5
+  --> $DIR/feature-gate-abi.rs:76:12
    |
 LL |     extern "rust-call" fn im4() {}
-   |     ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
+   |            ^^^^^^^^^^^
    |
    = note: for more information, see https://github.com/rust-lang/rust/issues/29625
    = help: add `#![feature(unboxed_closures)]` to the crate attributes to enable
 
 error[E0658]: msp430-interrupt ABI is experimental and subject to change
-  --> $DIR/feature-gate-abi.rs:77:5
+  --> $DIR/feature-gate-abi.rs:77:12
    |
 LL |     extern "msp430-interrupt" fn im5() {}
-   |     ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
+   |            ^^^^^^^^^^^^^^^^^^
    |
    = note: for more information, see https://github.com/rust-lang/rust/issues/38487
    = help: add `#![feature(abi_msp430_interrupt)]` to the crate attributes to enable
 
 error[E0658]: PTX ABIs are experimental and subject to change
-  --> $DIR/feature-gate-abi.rs:78:5
+  --> $DIR/feature-gate-abi.rs:78:12
    |
 LL |     extern "ptx-kernel" fn im6() {}
-   |     ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
+   |            ^^^^^^^^^^^^
    |
    = note: for more information, see https://github.com/rust-lang/rust/issues/38788
    = help: add `#![feature(abi_ptx)]` to the crate attributes to enable
 
 error[E0658]: x86-interrupt ABI is experimental and subject to change
-  --> $DIR/feature-gate-abi.rs:79:5
+  --> $DIR/feature-gate-abi.rs:79:12
    |
 LL |     extern "x86-interrupt" fn im7() {}
-   |     ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
+   |            ^^^^^^^^^^^^^^^
    |
    = note: for more information, see https://github.com/rust-lang/rust/issues/40180
    = help: add `#![feature(abi_x86_interrupt)]` to the crate attributes to enable
 
 error[E0658]: thiscall is experimental and subject to change
-  --> $DIR/feature-gate-abi.rs:80:5
+  --> $DIR/feature-gate-abi.rs:80:12
    |
 LL |     extern "thiscall" fn im8() {}
-   |     ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
+   |            ^^^^^^^^^^
    |
    = help: add `#![feature(abi_thiscall)]` to the crate attributes to enable
 
 error[E0658]: amdgpu-kernel ABI is experimental and subject to change
-  --> $DIR/feature-gate-abi.rs:81:5
+  --> $DIR/feature-gate-abi.rs:81:12
    |
 LL |     extern "amdgpu-kernel" fn im9() {}
-   |     ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
+   |            ^^^^^^^^^^^^^^^
    |
    = note: for more information, see https://github.com/rust-lang/rust/issues/51575
    = help: add `#![feature(abi_amdgpu_kernel)]` to the crate attributes to enable
 
 error[E0658]: efiapi ABI is experimental and subject to change
-  --> $DIR/feature-gate-abi.rs:82:5
+  --> $DIR/feature-gate-abi.rs:82:12
    |
 LL |     extern "efiapi" fn im10() {}
-   |     ^^^^^^^^^^^^^^^^^^^^^^^^^^^^
+   |            ^^^^^^^^
    |
    = note: for more information, see https://github.com/rust-lang/rust/issues/65815
    = help: add `#![feature(abi_efiapi)]` to the crate attributes to enable
 
 error[E0658]: intrinsics are subject to change
-  --> $DIR/feature-gate-abi.rs:86:11
+  --> $DIR/feature-gate-abi.rs:86:18
    |
 LL | type A1 = extern "rust-intrinsic" fn();
-   |           ^^^^^^^^^^^^^^^^^^^^^^^^^^^^
+   |                  ^^^^^^^^^^^^^^^^
    |
    = help: add `#![feature(intrinsics)]` to the crate attributes to enable
 
 error[E0658]: platform intrinsics are experimental and possibly buggy
-  --> $DIR/feature-gate-abi.rs:87:11
+  --> $DIR/feature-gate-abi.rs:87:18
    |
 LL | type A2 = extern "platform-intrinsic" fn();
-   |           ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
+   |                  ^^^^^^^^^^^^^^^^^^^^
    |
    = note: for more information, see https://github.com/rust-lang/rust/issues/27731
    = help: add `#![feature(platform_intrinsics)]` to the crate attributes to enable
 
 error[E0658]: vectorcall is experimental and subject to change
-  --> $DIR/feature-gate-abi.rs:88:11
+  --> $DIR/feature-gate-abi.rs:88:18
    |
 LL | type A3 = extern "vectorcall" fn();
-   |           ^^^^^^^^^^^^^^^^^^^^^^^^
+   |                  ^^^^^^^^^^^^
    |
    = help: add `#![feature(abi_vectorcall)]` to the crate attributes to enable
 
 error[E0658]: rust-call ABI is subject to change
-  --> $DIR/feature-gate-abi.rs:89:11
+  --> $DIR/feature-gate-abi.rs:89:18
    |
 LL | type A4 = extern "rust-call" fn();
-   |           ^^^^^^^^^^^^^^^^^^^^^^^
+   |                  ^^^^^^^^^^^
    |
    = note: for more information, see https://github.com/rust-lang/rust/issues/29625
    = help: add `#![feature(unboxed_closures)]` to the crate attributes to enable
 
 error[E0658]: msp430-interrupt ABI is experimental and subject to change
-  --> $DIR/feature-gate-abi.rs:90:11
+  --> $DIR/feature-gate-abi.rs:90:18
    |
 LL | type A5 = extern "msp430-interrupt" fn();
-   |           ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
+   |                  ^^^^^^^^^^^^^^^^^^
    |
    = note: for more information, see https://github.com/rust-lang/rust/issues/38487
    = help: add `#![feature(abi_msp430_interrupt)]` to the crate attributes to enable
 
 error[E0658]: PTX ABIs are experimental and subject to change
-  --> $DIR/feature-gate-abi.rs:91:11
+  --> $DIR/feature-gate-abi.rs:91:18
    |
 LL | type A6 = extern "ptx-kernel" fn ();
-   |           ^^^^^^^^^^^^^^^^^^^^^^^^^
+   |                  ^^^^^^^^^^^^
    |
    = note: for more information, see https://github.com/rust-lang/rust/issues/38788
    = help: add `#![feature(abi_ptx)]` to the crate attributes to enable
 
 error[E0658]: x86-interrupt ABI is experimental and subject to change
-  --> $DIR/feature-gate-abi.rs:92:11
+  --> $DIR/feature-gate-abi.rs:92:18
    |
 LL | type A7 = extern "x86-interrupt" fn();
-   |           ^^^^^^^^^^^^^^^^^^^^^^^^^^^
+   |                  ^^^^^^^^^^^^^^^
    |
    = note: for more information, see https://github.com/rust-lang/rust/issues/40180
    = help: add `#![feature(abi_x86_interrupt)]` to the crate attributes to enable
 
 error[E0658]: thiscall is experimental and subject to change
-  --> $DIR/feature-gate-abi.rs:93:11
+  --> $DIR/feature-gate-abi.rs:93:18
    |
 LL | type A8 = extern "thiscall" fn();
-   |           ^^^^^^^^^^^^^^^^^^^^^^
+   |                  ^^^^^^^^^^
    |
    = help: add `#![feature(abi_thiscall)]` to the crate attributes to enable
 
 error[E0658]: amdgpu-kernel ABI is experimental and subject to change
-  --> $DIR/feature-gate-abi.rs:94:11
+  --> $DIR/feature-gate-abi.rs:94:18
    |
 LL | type A9 = extern "amdgpu-kernel" fn();
-   |           ^^^^^^^^^^^^^^^^^^^^^^^^^^^
+   |                  ^^^^^^^^^^^^^^^
    |
    = note: for more information, see https://github.com/rust-lang/rust/issues/51575
    = help: add `#![feature(abi_amdgpu_kernel)]` to the crate attributes to enable
 
 error[E0658]: efiapi ABI is experimental and subject to change
-  --> $DIR/feature-gate-abi.rs:95:12
+  --> $DIR/feature-gate-abi.rs:95:19
    |
 LL | type A10 = extern "efiapi" fn();
-   |            ^^^^^^^^^^^^^^^^^^^^
+   |                   ^^^^^^^^
    |
    = note: for more information, see https://github.com/rust-lang/rust/issues/65815
    = help: add `#![feature(abi_efiapi)]` to the crate attributes to enable
 
 error[E0658]: intrinsics are subject to change
-  --> $DIR/feature-gate-abi.rs:98:1
+  --> $DIR/feature-gate-abi.rs:98:8
    |
 LL | extern "rust-intrinsic" {}
-   | ^^^^^^^^^^^^^^^^^^^^^^^^^^
+   |        ^^^^^^^^^^^^^^^^
    |
    = help: add `#![feature(intrinsics)]` to the crate attributes to enable
 
 error[E0658]: platform intrinsics are experimental and possibly buggy
-  --> $DIR/feature-gate-abi.rs:99:1
+  --> $DIR/feature-gate-abi.rs:99:8
    |
 LL | extern "platform-intrinsic" {}
-   | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
+   |        ^^^^^^^^^^^^^^^^^^^^
    |
    = note: for more information, see https://github.com/rust-lang/rust/issues/27731
    = help: add `#![feature(platform_intrinsics)]` to the crate attributes to enable
 
 error[E0658]: vectorcall is experimental and subject to change
-  --> $DIR/feature-gate-abi.rs:100:1
+  --> $DIR/feature-gate-abi.rs:100:8
    |
 LL | extern "vectorcall" {}
-   | ^^^^^^^^^^^^^^^^^^^^^^
+   |        ^^^^^^^^^^^^
    |
    = help: add `#![feature(abi_vectorcall)]` to the crate attributes to enable
 
 error[E0658]: rust-call ABI is subject to change
-  --> $DIR/feature-gate-abi.rs:101:1
+  --> $DIR/feature-gate-abi.rs:101:8
    |
 LL | extern "rust-call" {}
-   | ^^^^^^^^^^^^^^^^^^^^^
+   |        ^^^^^^^^^^^
    |
    = note: for more information, see https://github.com/rust-lang/rust/issues/29625
    = help: add `#![feature(unboxed_closures)]` to the crate attributes to enable
 
 error[E0658]: msp430-interrupt ABI is experimental and subject to change
-  --> $DIR/feature-gate-abi.rs:102:1
+  --> $DIR/feature-gate-abi.rs:102:8
    |
 LL | extern "msp430-interrupt" {}
-   | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^
+   |        ^^^^^^^^^^^^^^^^^^
    |
    = note: for more information, see https://github.com/rust-lang/rust/issues/38487
    = help: add `#![feature(abi_msp430_interrupt)]` to the crate attributes to enable
 
 error[E0658]: PTX ABIs are experimental and subject to change
-  --> $DIR/feature-gate-abi.rs:103:1
+  --> $DIR/feature-gate-abi.rs:103:8
    |
 LL | extern "ptx-kernel" {}
-   | ^^^^^^^^^^^^^^^^^^^^^^
+   |        ^^^^^^^^^^^^
    |
    = note: for more information, see https://github.com/rust-lang/rust/issues/38788
    = help: add `#![feature(abi_ptx)]` to the crate attributes to enable
 
 error[E0658]: x86-interrupt ABI is experimental and subject to change
-  --> $DIR/feature-gate-abi.rs:104:1
+  --> $DIR/feature-gate-abi.rs:104:8
    |
 LL | extern "x86-interrupt" {}
-   | ^^^^^^^^^^^^^^^^^^^^^^^^^
+   |        ^^^^^^^^^^^^^^^
    |
    = note: for more information, see https://github.com/rust-lang/rust/issues/40180
    = help: add `#![feature(abi_x86_interrupt)]` to the crate attributes to enable
 
 error[E0658]: thiscall is experimental and subject to change
-  --> $DIR/feature-gate-abi.rs:105:1
+  --> $DIR/feature-gate-abi.rs:105:8
    |
 LL | extern "thiscall" {}
-   | ^^^^^^^^^^^^^^^^^^^^
+   |        ^^^^^^^^^^
    |
    = help: add `#![feature(abi_thiscall)]` to the crate attributes to enable
 
 error[E0658]: amdgpu-kernel ABI is experimental and subject to change
-  --> $DIR/feature-gate-abi.rs:106:1
+  --> $DIR/feature-gate-abi.rs:106:8
    |
 LL | extern "amdgpu-kernel" {}
-   | ^^^^^^^^^^^^^^^^^^^^^^^^^
+   |        ^^^^^^^^^^^^^^^
    |
    = note: for more information, see https://github.com/rust-lang/rust/issues/51575
    = help: add `#![feature(abi_amdgpu_kernel)]` to the crate attributes to enable
 
 error[E0658]: efiapi ABI is experimental and subject to change
-  --> $DIR/feature-gate-abi.rs:107:1
+  --> $DIR/feature-gate-abi.rs:107:8
    |
 LL | extern "efiapi" {}
-   | ^^^^^^^^^^^^^^^^^^
+   |        ^^^^^^^^
    |
    = note: for more information, see https://github.com/rust-lang/rust/issues/65815
    = help: add `#![feature(abi_efiapi)]` to the crate attributes to enable
diff --git a/src/test/ui/feature-gates/feature-gate-abi_unadjusted.stderr b/src/test/ui/feature-gates/feature-gate-abi_unadjusted.stderr
index 4954a7d1f71f6..1757befec35c0 100644
--- a/src/test/ui/feature-gates/feature-gate-abi_unadjusted.stderr
+++ b/src/test/ui/feature-gates/feature-gate-abi_unadjusted.stderr
@@ -1,10 +1,8 @@
 error[E0658]: unadjusted ABI is an implementation detail and perma-unstable
-  --> $DIR/feature-gate-abi_unadjusted.rs:1:1
+  --> $DIR/feature-gate-abi_unadjusted.rs:1:8
    |
-LL | / extern "unadjusted" fn foo() {
-LL | |
-LL | | }
-   | |_^
+LL | extern "unadjusted" fn foo() {
+   |        ^^^^^^^^^^^^
    |
    = help: add `#![feature(abi_unadjusted)]` to the crate attributes to enable
 
diff --git a/src/test/ui/feature-gates/feature-gate-intrinsics.stderr b/src/test/ui/feature-gates/feature-gate-intrinsics.stderr
index 101a10e8df71f..8f943d357ce02 100644
--- a/src/test/ui/feature-gates/feature-gate-intrinsics.stderr
+++ b/src/test/ui/feature-gates/feature-gate-intrinsics.stderr
@@ -1,18 +1,16 @@
 error[E0658]: intrinsics are subject to change
-  --> $DIR/feature-gate-intrinsics.rs:1:1
+  --> $DIR/feature-gate-intrinsics.rs:1:8
    |
-LL | / extern "rust-intrinsic" {
-LL | |     fn bar();
-LL | | }
-   | |_^
+LL | extern "rust-intrinsic" {
+   |        ^^^^^^^^^^^^^^^^
    |
    = help: add `#![feature(intrinsics)]` to the crate attributes to enable
 
 error[E0658]: intrinsics are subject to change
-  --> $DIR/feature-gate-intrinsics.rs:5:1
+  --> $DIR/feature-gate-intrinsics.rs:5:8
    |
 LL | extern "rust-intrinsic" fn baz() {}
-   | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
+   |        ^^^^^^^^^^^^^^^^
    |
    = help: add `#![feature(intrinsics)]` to the crate attributes to enable
 
diff --git a/src/test/ui/feature-gates/feature-gate-unboxed-closures-manual-impls.stderr b/src/test/ui/feature-gates/feature-gate-unboxed-closures-manual-impls.stderr
index c05379c71eeaf..657bf13c8739e 100644
--- a/src/test/ui/feature-gates/feature-gate-unboxed-closures-manual-impls.stderr
+++ b/src/test/ui/feature-gates/feature-gate-unboxed-closures-manual-impls.stderr
@@ -1,35 +1,35 @@
 error[E0658]: rust-call ABI is subject to change
-  --> $DIR/feature-gate-unboxed-closures-manual-impls.rs:11:5
+  --> $DIR/feature-gate-unboxed-closures-manual-impls.rs:11:12
    |
 LL |     extern "rust-call" fn call(self, args: ()) -> () {}
-   |     ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
+   |            ^^^^^^^^^^^
    |
    = note: for more information, see https://github.com/rust-lang/rust/issues/29625
    = help: add `#![feature(unboxed_closures)]` to the crate attributes to enable
 
 error[E0658]: rust-call ABI is subject to change
-  --> $DIR/feature-gate-unboxed-closures-manual-impls.rs:17:5
+  --> $DIR/feature-gate-unboxed-closures-manual-impls.rs:17:12
    |
 LL |     extern "rust-call" fn call_once(self, args: ()) -> () {}
-   |     ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
+   |            ^^^^^^^^^^^
    |
    = note: for more information, see https://github.com/rust-lang/rust/issues/29625
    = help: add `#![feature(unboxed_closures)]` to the crate attributes to enable
 
 error[E0658]: rust-call ABI is subject to change
-  --> $DIR/feature-gate-unboxed-closures-manual-impls.rs:23:5
+  --> $DIR/feature-gate-unboxed-closures-manual-impls.rs:23:12
    |
 LL |     extern "rust-call" fn call_mut(&self, args: ()) -> () {}
-   |     ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
+   |            ^^^^^^^^^^^
    |
    = note: for more information, see https://github.com/rust-lang/rust/issues/29625
    = help: add `#![feature(unboxed_closures)]` to the crate attributes to enable
 
 error[E0658]: rust-call ABI is subject to change
-  --> $DIR/feature-gate-unboxed-closures-manual-impls.rs:29:5
+  --> $DIR/feature-gate-unboxed-closures-manual-impls.rs:29:12
    |
 LL |     extern "rust-call" fn call_once(&self, args: ()) -> () {}
-   |     ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
+   |            ^^^^^^^^^^^
    |
    = note: for more information, see https://github.com/rust-lang/rust/issues/29625
    = help: add `#![feature(unboxed_closures)]` to the crate attributes to enable
diff --git a/src/test/ui/feature-gates/feature-gate-unboxed-closures.stderr b/src/test/ui/feature-gates/feature-gate-unboxed-closures.stderr
index 723c6619887aa..f343a42eb8fa9 100644
--- a/src/test/ui/feature-gates/feature-gate-unboxed-closures.stderr
+++ b/src/test/ui/feature-gates/feature-gate-unboxed-closures.stderr
@@ -1,10 +1,8 @@
 error[E0658]: rust-call ABI is subject to change
-  --> $DIR/feature-gate-unboxed-closures.rs:9:5
+  --> $DIR/feature-gate-unboxed-closures.rs:9:12
    |
-LL | /     extern "rust-call" fn call_once(self, (a, b): (u32, u32)) -> u32 {
-LL | |         a + b
-LL | |     }
-   | |_____^
+LL |     extern "rust-call" fn call_once(self, (a, b): (u32, u32)) -> u32 {
+   |            ^^^^^^^^^^^
    |
    = note: for more information, see https://github.com/rust-lang/rust/issues/29625
    = help: add `#![feature(unboxed_closures)]` to the crate attributes to enable

From 9ffdc3b4fffcabaf6a2e3dbaf21cc72da885685e Mon Sep 17 00:00:00 2001
From: Mazdak Farrokhzad <twingoow@gmail.com>
Date: Sun, 27 Oct 2019 23:22:59 +0100
Subject: [PATCH 06/10] cleanup can_begin_const_arg

---
 src/libsyntax/parse/token.rs | 4 +---
 1 file changed, 1 insertion(+), 3 deletions(-)

diff --git a/src/libsyntax/parse/token.rs b/src/libsyntax/parse/token.rs
index 03e77b199cc3b..ea82aad0eaec4 100644
--- a/src/libsyntax/parse/token.rs
+++ b/src/libsyntax/parse/token.rs
@@ -381,9 +381,7 @@ impl Token {
         match self.kind {
             OpenDelim(Brace) => true,
             Interpolated(ref nt) => match **nt {
-                NtExpr(..) => true,
-                NtBlock(..) => true,
-                NtLiteral(..) => true,
+                NtExpr(..) | NtBlock(..) | NtLiteral(..) => true,
                 _ => false,
             }
             _ => self.can_begin_literal_or_bool(),

From cf75e6e5da6da351f9eb3da92814380457afdf4f Mon Sep 17 00:00:00 2001
From: Mazdak Farrokhzad <twingoow@gmail.com>
Date: Mon, 28 Oct 2019 00:29:23 +0100
Subject: [PATCH 07/10] parser: allow ABIs from literal macro fragments

---
 src/libsyntax/parse/parser.rs                 | 40 +++++++++++++------
 src/libsyntax/parse/parser/expr.rs            |  6 ++-
 src/libsyntax/parse/parser/item.rs            |  2 +-
 src/libsyntax/parse/token.rs                  |  7 ----
 src/test/ui/parser/bad-lit-suffixes.rs        |  4 +-
 src/test/ui/parser/bad-lit-suffixes.stderr    |  4 +-
 .../extern-abi-from-mac-literal-frag.rs       | 26 ++++++++++++
 7 files changed, 63 insertions(+), 26 deletions(-)
 create mode 100644 src/test/ui/parser/extern-abi-from-mac-literal-frag.rs

diff --git a/src/libsyntax/parse/parser.rs b/src/libsyntax/parse/parser.rs
index cf58cf9f13a52..bbb6e0229edfa 100644
--- a/src/libsyntax/parse/parser.rs
+++ b/src/libsyntax/parse/parser.rs
@@ -1206,27 +1206,41 @@ impl<'a> Parser<'a> {
         Ok(())
     }
 
-    /// Parses `extern` followed by an optional ABI string, or nothing.
+    /// Parses `extern string_literal?`.
+    /// If `extern` is not found, the Rust ABI is used.
+    /// If `extern` is found and a `string_literal` does not follow, the C ABI is used.
     fn parse_extern_abi(&mut self) -> PResult<'a, Abi> {
         Ok(if self.eat_keyword(kw::Extern) {
-            let ext_sp = self.prev_span;
-            self.parse_opt_abi()?.unwrap_or_else(|| Abi::new(sym::C, ext_sp))
+            self.parse_opt_abi()?
         } else {
             Abi::default()
         })
     }
 
-    /// Parses a string as an ABI spec on an extern type or module.
-    fn parse_opt_abi(&mut self) -> PResult<'a, Option<Abi>> {
-        match self.token.kind {
-            token::Literal(token::Lit { kind: token::Str, symbol, suffix }) |
-            token::Literal(token::Lit { kind: token::StrRaw(..), symbol, suffix }) => {
-                self.expect_no_suffix(self.token.span, "an ABI spec", suffix);
-                self.bump();
-                Ok(Some(Abi::new(symbol, self.prev_span)))
+    /// Parses a string literal as an ABI spec.
+    /// If one is not found, the "C" ABI is used.
+    fn parse_opt_abi(&mut self) -> PResult<'a, Abi> {
+        let span = if self.token.can_begin_literal_or_bool() {
+            let ast::Lit { span, kind, .. } = self.parse_lit()?;
+            match kind {
+                ast::LitKind::Str(symbol, _) => return Ok(Abi::new(symbol, span)),
+                ast::LitKind::Err(_) => {}
+                _ => {
+                    self.struct_span_err(span, "non-string ABI literal")
+                        .span_suggestion(
+                            span,
+                            "specify the ABI with a string literal",
+                            "\"C\"".to_string(),
+                            Applicability::MaybeIncorrect,
+                        )
+                        .emit();
+                }
             }
-            _ => Ok(None),
-        }
+            span
+        } else {
+            self.prev_span
+        };
+        Ok(Abi::new(sym::C, span))
     }
 
     /// We are parsing `async fn`. If we are on Rust 2015, emit an error.
diff --git a/src/libsyntax/parse/parser/expr.rs b/src/libsyntax/parse/parser/expr.rs
index 97b1092452aaf..80ea8f380fbad 100644
--- a/src/libsyntax/parse/parser/expr.rs
+++ b/src/libsyntax/parse/parser/expr.rs
@@ -1116,7 +1116,11 @@ impl<'a> Parser<'a> {
                 Err(self.span_fatal(token.span, &msg))
             }
             Err(err) => {
-                let (lit, span) = (token.expect_lit(), token.span);
+                let span = token.span;
+                let lit = match token.kind {
+                    token::Literal(lit) => lit,
+                    _ => unreachable!(),
+                };
                 self.bump();
                 self.error_literal_from_token(err, lit, span);
                 // Pack possible quotes and prefixes from the original literal into
diff --git a/src/libsyntax/parse/parser/item.rs b/src/libsyntax/parse/parser/item.rs
index 46b93ab236a7d..54f08e69070f3 100644
--- a/src/libsyntax/parse/parser/item.rs
+++ b/src/libsyntax/parse/parser/item.rs
@@ -110,7 +110,7 @@ impl<'a> Parser<'a> {
                 return Ok(Some(self.parse_item_extern_crate(lo, vis, attrs)?));
             }
 
-            let abi = self.parse_opt_abi()?.unwrap_or_else(|| Abi::new(sym::C, extern_sp));
+            let abi = self.parse_opt_abi()?;
 
             if self.eat_keyword(kw::Fn) {
                 // EXTERN FUNCTION ITEM
diff --git a/src/libsyntax/parse/token.rs b/src/libsyntax/parse/token.rs
index ea82aad0eaec4..6f3da344ccf88 100644
--- a/src/libsyntax/parse/token.rs
+++ b/src/libsyntax/parse/token.rs
@@ -402,13 +402,6 @@ impl Token {
         }
     }
 
-    crate fn expect_lit(&self) -> Lit {
-        match self.kind {
-            Literal(lit) => lit,
-            _ => panic!("`expect_lit` called on non-literal"),
-        }
-    }
-
     /// Returns `true` if the token is any literal, a minus (which can prefix a literal,
     /// for example a '-42', or one of the boolean idents).
     pub fn can_begin_literal_or_bool(&self) -> bool {
diff --git a/src/test/ui/parser/bad-lit-suffixes.rs b/src/test/ui/parser/bad-lit-suffixes.rs
index 9f301db09956e..7db83674efc60 100644
--- a/src/test/ui/parser/bad-lit-suffixes.rs
+++ b/src/test/ui/parser/bad-lit-suffixes.rs
@@ -1,9 +1,9 @@
 extern
-    "C"suffix //~ ERROR suffixes on an ABI spec are invalid
+    "C"suffix //~ ERROR suffixes on a string literal are invalid
     fn foo() {}
 
 extern
-    "C"suffix //~ ERROR suffixes on an ABI spec are invalid
+    "C"suffix //~ ERROR suffixes on a string literal are invalid
 {}
 
 fn main() {
diff --git a/src/test/ui/parser/bad-lit-suffixes.stderr b/src/test/ui/parser/bad-lit-suffixes.stderr
index 208fcf43d9177..6b0049298ffd2 100644
--- a/src/test/ui/parser/bad-lit-suffixes.stderr
+++ b/src/test/ui/parser/bad-lit-suffixes.stderr
@@ -1,10 +1,10 @@
-error: suffixes on an ABI spec are invalid
+error: suffixes on a string literal are invalid
   --> $DIR/bad-lit-suffixes.rs:2:5
    |
 LL |     "C"suffix
    |     ^^^^^^^^^ invalid suffix `suffix`
 
-error: suffixes on an ABI spec are invalid
+error: suffixes on a string literal are invalid
   --> $DIR/bad-lit-suffixes.rs:6:5
    |
 LL |     "C"suffix
diff --git a/src/test/ui/parser/extern-abi-from-mac-literal-frag.rs b/src/test/ui/parser/extern-abi-from-mac-literal-frag.rs
new file mode 100644
index 0000000000000..cb23f2c808c34
--- /dev/null
+++ b/src/test/ui/parser/extern-abi-from-mac-literal-frag.rs
@@ -0,0 +1,26 @@
+// check-pass
+
+// In this test we check that the parser accepts an ABI string when it
+// comes from a macro `literal` fragment as opposed to a hardcoded string.
+
+fn main() {}
+
+macro_rules! abi_from_lit_frag {
+    ($abi:literal) => {
+        extern $abi {
+            fn _import();
+        }
+
+        extern $abi fn _export() {}
+
+        type _PTR = extern $abi fn();
+    }
+}
+
+mod rust {
+    abi_from_lit_frag!("Rust");
+}
+
+mod c {
+    abi_from_lit_frag!("C");
+}

From 4c8544ba59a42527cb8c5d6d792f89b64c1a017b Mon Sep 17 00:00:00 2001
From: Mazdak Farrokhzad <twingoow@gmail.com>
Date: Mon, 28 Oct 2019 04:13:38 +0100
Subject: [PATCH 08/10] test that parser is oblivious to set of ABIs

---
 src/test/ui/parser/extern-abi-syntactic.rs | 17 +++++++++++++++++
 1 file changed, 17 insertions(+)
 create mode 100644 src/test/ui/parser/extern-abi-syntactic.rs

diff --git a/src/test/ui/parser/extern-abi-syntactic.rs b/src/test/ui/parser/extern-abi-syntactic.rs
new file mode 100644
index 0000000000000..7d2bbfe8a0163
--- /dev/null
+++ b/src/test/ui/parser/extern-abi-syntactic.rs
@@ -0,0 +1,17 @@
+// check-pass
+
+// Check that from the grammar's point of view,
+// the specific set of ABIs is not part of it.
+
+fn main() {}
+
+#[cfg(FALSE)]
+extern "some_abi_that_we_are_sure_does_not_exist_semantically" fn foo() {}
+
+#[cfg(FALSE)]
+extern "some_abi_that_we_are_sure_does_not_exist_semantically" {
+    fn foo();
+}
+
+#[cfg(FALSE)]
+type T = extern "some_abi_that_we_are_sure_does_not_exist_semantically" fn();

From d6c93911a41933264d899df18a0bc01e4bd02505 Mon Sep 17 00:00:00 2001
From: Mazdak Farrokhzad <twingoow@gmail.com>
Date: Wed, 30 Oct 2019 13:53:53 +0100
Subject: [PATCH 09/10] test that extern lits accept raw strings annd escapes

---
 src/test/ui/parser/extern-abi-raw-strings.rs     | 13 +++++++++++++
 src/test/ui/parser/extern-abi-string-escaping.rs | 13 +++++++++++++
 2 files changed, 26 insertions(+)
 create mode 100644 src/test/ui/parser/extern-abi-raw-strings.rs
 create mode 100644 src/test/ui/parser/extern-abi-string-escaping.rs

diff --git a/src/test/ui/parser/extern-abi-raw-strings.rs b/src/test/ui/parser/extern-abi-raw-strings.rs
new file mode 100644
index 0000000000000..fad855a21f6b1
--- /dev/null
+++ b/src/test/ui/parser/extern-abi-raw-strings.rs
@@ -0,0 +1,13 @@
+// check-pass
+
+// Check that the string literal in `extern lit` will accept raw strings.
+
+fn main() {}
+
+extern r#"C"# fn foo() {}
+
+extern r#"C"# {
+    fn bar();
+}
+
+type T = extern r#"C"# fn();
diff --git a/src/test/ui/parser/extern-abi-string-escaping.rs b/src/test/ui/parser/extern-abi-string-escaping.rs
new file mode 100644
index 0000000000000..87bd31aabb67d
--- /dev/null
+++ b/src/test/ui/parser/extern-abi-string-escaping.rs
@@ -0,0 +1,13 @@
+// check-pass
+
+// Check that the string literal in `extern lit` will escapes.
+
+fn main() {}
+
+extern "\x43" fn foo() {}
+
+extern "\x43" {
+    fn bar();
+}
+
+type T = extern "\x43" fn();

From 0d15968052afe4ba3f533f2f3f4e2b9fe18c3a65 Mon Sep 17 00:00:00 2001
From: Mazdak Farrokhzad <twingoow@gmail.com>
Date: Mon, 28 Oct 2019 03:46:22 +0100
Subject: [PATCH 10/10] syntax: use distinct FloatTy from rustc_target.

We also sever syntax's dependency on rustc_target as a result.
This should slightly improve pipe-lining.

Moreover, some cleanup is done in related code.
---
 Cargo.lock                                    |  3 -
 src/librustc/ich/impls_syntax.rs              | 10 +-
 src/librustc/ty/layout.rs                     |  5 +-
 src/librustc/ty/print/obsolete.rs             | 18 +---
 src/librustc/ty/print/pretty.rs               | 18 ++--
 .../debuginfo/metadata.rs                     |  6 +-
 src/librustc_codegen_llvm/intrinsic.rs        |  5 +-
 .../debuginfo/type_names.rs                   |  6 +-
 src/librustc_interface/Cargo.toml             |  4 +-
 src/librustc_lint/types.rs                    | 36 ++++----
 src/librustc_mir/hair/constant.rs             |  5 +-
 src/librustc_save_analysis/Cargo.toml         |  1 -
 src/librustc_target/abi/mod.rs                | 40 +-------
 src/librustc_typeck/check/mod.rs              |  4 +-
 src/libsyntax/Cargo.toml                      |  1 -
 src/libsyntax/ast.rs                          | 91 +++++++++++--------
 src/libsyntax/parse/literal.rs                | 23 ++---
 src/libsyntax_expand/Cargo.toml               |  1 -
 src/libsyntax_ext/concat.rs                   |  3 +-
 19 files changed, 123 insertions(+), 157 deletions(-)

diff --git a/Cargo.lock b/Cargo.lock
index 2c161e4d27a9d..63310b40e2329 100644
--- a/Cargo.lock
+++ b/Cargo.lock
@@ -3766,7 +3766,6 @@ dependencies = [
  "rustc",
  "rustc_codegen_utils",
  "rustc_data_structures",
- "rustc_target",
  "serde_json",
  "syntax",
  "syntax_pos",
@@ -4360,7 +4359,6 @@ dependencies = [
  "rustc_errors",
  "rustc_index",
  "rustc_lexer",
- "rustc_target",
  "scoped-tls",
  "serialize",
  "smallvec",
@@ -4378,7 +4376,6 @@ dependencies = [
  "rustc_errors",
  "rustc_index",
  "rustc_lexer",
- "rustc_target",
  "scoped-tls",
  "serialize",
  "smallvec",
diff --git a/src/librustc/ich/impls_syntax.rs b/src/librustc/ich/impls_syntax.rs
index 4fd4e25f64110..b9015410e77ec 100644
--- a/src/librustc/ich/impls_syntax.rs
+++ b/src/librustc/ich/impls_syntax.rs
@@ -124,7 +124,6 @@ for ::syntax::attr::StabilityLevel {
 
 impl_stable_hash_for!(struct ::syntax::attr::RustcDeprecation { since, reason, suggestion });
 
-
 impl_stable_hash_for!(enum ::syntax::attr::IntType {
     SignedInt(int_ty),
     UnsignedInt(uint_ty)
@@ -136,6 +135,11 @@ impl_stable_hash_for!(enum ::syntax::ast::LitIntType {
     Unsuffixed
 });
 
+impl_stable_hash_for!(enum ::syntax::ast::LitFloatType {
+    Suffixed(float_ty),
+    Unsuffixed
+});
+
 impl_stable_hash_for!(struct ::syntax::ast::Lit {
     kind,
     token,
@@ -148,8 +152,7 @@ impl_stable_hash_for!(enum ::syntax::ast::LitKind {
     Byte(value),
     Char(value),
     Int(value, lit_int_type),
-    Float(value, float_ty),
-    FloatUnsuffixed(value),
+    Float(value, lit_float_type),
     Bool(value),
     Err(value)
 });
@@ -159,6 +162,7 @@ impl_stable_hash_for_spanned!(::syntax::ast::LitKind);
 impl_stable_hash_for!(enum ::syntax::ast::IntTy { Isize, I8, I16, I32, I64, I128 });
 impl_stable_hash_for!(enum ::syntax::ast::UintTy { Usize, U8, U16, U32, U64, U128 });
 impl_stable_hash_for!(enum ::syntax::ast::FloatTy { F32, F64 });
+impl_stable_hash_for!(enum ::rustc_target::abi::FloatTy { F32, F64 });
 impl_stable_hash_for!(enum ::syntax::ast::Unsafety { Unsafe, Normal });
 impl_stable_hash_for!(enum ::syntax::ast::Constness { Const, NotConst });
 impl_stable_hash_for!(enum ::syntax::ast::Defaultness { Default, Final });
diff --git a/src/librustc/ty/layout.rs b/src/librustc/ty/layout.rs
index e82232ac10f7b..5a2416f7aef4f 100644
--- a/src/librustc/ty/layout.rs
+++ b/src/librustc/ty/layout.rs
@@ -538,7 +538,10 @@ impl<'tcx> LayoutCx<'tcx, TyCtxt<'tcx>> {
             ty::Uint(ity) => {
                 scalar(Int(Integer::from_attr(dl, attr::UnsignedInt(ity)), false))
             }
-            ty::Float(fty) => scalar(Float(fty)),
+            ty::Float(fty) => scalar(Float(match fty {
+                ast::FloatTy::F32 => FloatTy::F32,
+                ast::FloatTy::F64 => FloatTy::F64,
+            })),
             ty::FnPtr(_) => {
                 let mut ptr = scalar_unit(Pointer);
                 ptr.valid_range = 1..=*ptr.valid_range.end();
diff --git a/src/librustc/ty/print/obsolete.rs b/src/librustc/ty/print/obsolete.rs
index e72916de6a9c7..d25f302cf889e 100644
--- a/src/librustc/ty/print/obsolete.rs
+++ b/src/librustc/ty/print/obsolete.rs
@@ -12,7 +12,6 @@ use rustc::ty::{self, Const, Instance, Ty, TyCtxt};
 use rustc::{bug, hir};
 use std::fmt::Write;
 use std::iter;
-use syntax::ast;
 
 /// Same as `unique_type_name()` but with the result pushed onto the given
 /// `output` parameter.
@@ -39,20 +38,9 @@ impl DefPathBasedNames<'tcx> {
             ty::Char => output.push_str("char"),
             ty::Str => output.push_str("str"),
             ty::Never => output.push_str("!"),
-            ty::Int(ast::IntTy::Isize) => output.push_str("isize"),
-            ty::Int(ast::IntTy::I8) => output.push_str("i8"),
-            ty::Int(ast::IntTy::I16) => output.push_str("i16"),
-            ty::Int(ast::IntTy::I32) => output.push_str("i32"),
-            ty::Int(ast::IntTy::I64) => output.push_str("i64"),
-            ty::Int(ast::IntTy::I128) => output.push_str("i128"),
-            ty::Uint(ast::UintTy::Usize) => output.push_str("usize"),
-            ty::Uint(ast::UintTy::U8) => output.push_str("u8"),
-            ty::Uint(ast::UintTy::U16) => output.push_str("u16"),
-            ty::Uint(ast::UintTy::U32) => output.push_str("u32"),
-            ty::Uint(ast::UintTy::U64) => output.push_str("u64"),
-            ty::Uint(ast::UintTy::U128) => output.push_str("u128"),
-            ty::Float(ast::FloatTy::F32) => output.push_str("f32"),
-            ty::Float(ast::FloatTy::F64) => output.push_str("f64"),
+            ty::Int(ty) => output.push_str(ty.name_str()),
+            ty::Uint(ty) => output.push_str(ty.name_str()),
+            ty::Float(ty) => output.push_str(ty.name_str()),
             ty::Adt(adt_def, substs) => {
                 self.push_def_path(adt_def.did, output);
                 self.push_generic_params(substs, iter::empty(), output, debug);
diff --git a/src/librustc/ty/print/pretty.rs b/src/librustc/ty/print/pretty.rs
index 8a98a5d83615f..4d1fece2cb9c9 100644
--- a/src/librustc/ty/print/pretty.rs
+++ b/src/librustc/ty/print/pretty.rs
@@ -466,9 +466,9 @@ pub trait PrettyPrinter<'tcx>:
         match ty.kind {
             ty::Bool => p!(write("bool")),
             ty::Char => p!(write("char")),
-            ty::Int(t) => p!(write("{}", t.ty_to_string())),
-            ty::Uint(t) => p!(write("{}", t.ty_to_string())),
-            ty::Float(t) => p!(write("{}", t.ty_to_string())),
+            ty::Int(t) => p!(write("{}", t.name_str())),
+            ty::Uint(t) => p!(write("{}", t.name_str())),
+            ty::Float(t) => p!(write("{}", t.name_str())),
             ty::RawPtr(ref tm) => {
                 p!(write("*{} ", match tm.mutbl {
                     hir::MutMutable => "mut",
@@ -895,10 +895,11 @@ pub trait PrettyPrinter<'tcx>:
                 let bit_size = Integer::from_attr(&self.tcx(), UnsignedInt(*ui)).size();
                 let max = truncate(u128::max_value(), bit_size);
 
+                let ui_str = ui.name_str();
                 if data == max {
-                    p!(write("std::{}::MAX", ui))
+                    p!(write("std::{}::MAX", ui_str))
                 } else {
-                    p!(write("{}{}", data, ui))
+                    p!(write("{}{}", data, ui_str))
                 };
             },
             (ConstValue::Scalar(Scalar::Raw { data, .. }), ty::Int(i)) => {
@@ -911,10 +912,11 @@ pub trait PrettyPrinter<'tcx>:
                 let size = self.tcx().layout_of(ty::ParamEnv::empty().and(ty))
                     .unwrap()
                     .size;
+                let i_str = i.name_str();
                 match data {
-                    d if d == min => p!(write("std::{}::MIN", i)),
-                    d if d == max => p!(write("std::{}::MAX", i)),
-                    _ => p!(write("{}{}", sign_extend(data, size) as i128, i))
+                    d if d == min => p!(write("std::{}::MIN", i_str)),
+                    d if d == max => p!(write("std::{}::MAX", i_str)),
+                    _ => p!(write("{}{}", sign_extend(data, size) as i128, i_str))
                 }
             },
             (ConstValue::Scalar(Scalar::Raw { data, .. }), ty::Char) =>
diff --git a/src/librustc_codegen_llvm/debuginfo/metadata.rs b/src/librustc_codegen_llvm/debuginfo/metadata.rs
index f0148a21ae670..5f18bb1700c14 100644
--- a/src/librustc_codegen_llvm/debuginfo/metadata.rs
+++ b/src/librustc_codegen_llvm/debuginfo/metadata.rs
@@ -843,13 +843,13 @@ fn basic_type_metadata(cx: &CodegenCx<'ll, 'tcx>, t: Ty<'tcx>) -> &'ll DIType {
         ty::Bool => ("bool", DW_ATE_boolean),
         ty::Char => ("char", DW_ATE_unsigned_char),
         ty::Int(int_ty) => {
-            (int_ty.ty_to_string(), DW_ATE_signed)
+            (int_ty.name_str(), DW_ATE_signed)
         },
         ty::Uint(uint_ty) => {
-            (uint_ty.ty_to_string(), DW_ATE_unsigned)
+            (uint_ty.name_str(), DW_ATE_unsigned)
         },
         ty::Float(float_ty) => {
-            (float_ty.ty_to_string(), DW_ATE_float)
+            (float_ty.name_str(), DW_ATE_float)
         },
         _ => bug!("debuginfo::basic_type_metadata - t is invalid type")
     };
diff --git a/src/librustc_codegen_llvm/intrinsic.rs b/src/librustc_codegen_llvm/intrinsic.rs
index 3df8d4c26903b..75c8a356ef5e0 100644
--- a/src/librustc_codegen_llvm/intrinsic.rs
+++ b/src/librustc_codegen_llvm/intrinsic.rs
@@ -18,7 +18,8 @@ use rustc::ty::layout::{self, LayoutOf, HasTyCtxt, Primitive};
 use rustc::mir::interpret::GlobalId;
 use rustc_codegen_ssa::common::{IntPredicate, TypeKind};
 use rustc::hir;
-use syntax::ast::{self, FloatTy};
+use rustc_target::abi::FloatTy;
+use syntax::ast;
 
 use rustc_codegen_ssa::common::span_invalid_monomorphization_error;
 use rustc_codegen_ssa::traits::*;
@@ -1314,7 +1315,7 @@ fn generic_simd_intrinsic(
             },
             ty::Float(f) => {
                 return_error!("unsupported element type `{}` of floating-point vector `{}`",
-                              f, in_ty);
+                              f.name_str(), in_ty);
             },
             _ => {
                 return_error!("`{}` is not a floating-point type", in_ty);
diff --git a/src/librustc_codegen_ssa/debuginfo/type_names.rs b/src/librustc_codegen_ssa/debuginfo/type_names.rs
index 166a74fe48795..372aefacb95f2 100644
--- a/src/librustc_codegen_ssa/debuginfo/type_names.rs
+++ b/src/librustc_codegen_ssa/debuginfo/type_names.rs
@@ -37,9 +37,9 @@ pub fn push_debuginfo_type_name<'tcx>(
         ty::Char => output.push_str("char"),
         ty::Str => output.push_str("str"),
         ty::Never => output.push_str("!"),
-        ty::Int(int_ty) => output.push_str(int_ty.ty_to_string()),
-        ty::Uint(uint_ty) => output.push_str(uint_ty.ty_to_string()),
-        ty::Float(float_ty) => output.push_str(float_ty.ty_to_string()),
+        ty::Int(int_ty) => output.push_str(int_ty.name_str()),
+        ty::Uint(uint_ty) => output.push_str(uint_ty.name_str()),
+        ty::Float(float_ty) => output.push_str(float_ty.name_str()),
         ty::Foreign(def_id) => push_item_name(tcx, def_id, qualified, output),
         ty::Adt(def, substs) => {
             push_item_name(tcx, def.did, qualified, output);
diff --git a/src/librustc_interface/Cargo.toml b/src/librustc_interface/Cargo.toml
index 0d8d765a572c2..1e15e15253a2e 100644
--- a/src/librustc_interface/Cargo.toml
+++ b/src/librustc_interface/Cargo.toml
@@ -27,7 +27,6 @@ rustc_codegen_utils = { path = "../librustc_codegen_utils" }
 rustc_metadata = { path = "../librustc_metadata" }
 rustc_mir = { path = "../librustc_mir" }
 rustc_passes = { path = "../librustc_passes" }
-rustc_target = { path = "../librustc_target" }
 rustc_typeck = { path = "../librustc_typeck" }
 rustc_lint = { path = "../librustc_lint" }
 rustc_errors = { path = "../librustc_errors" }
@@ -36,3 +35,6 @@ rustc_privacy = { path = "../librustc_privacy" }
 rustc_resolve = { path = "../librustc_resolve" }
 tempfile = "3.0.5"
 once_cell = "1"
+
+[dev-dependencies]
+rustc_target = { path = "../librustc_target" }
diff --git a/src/librustc_lint/types.rs b/src/librustc_lint/types.rs
index aa6dfa50dddf3..9a4e981081fcf 100644
--- a/src/librustc_lint/types.rs
+++ b/src/librustc_lint/types.rs
@@ -68,7 +68,7 @@ fn lint_overflowing_range_endpoint<'a, 'tcx>(
     max: u128,
     expr: &'tcx hir::Expr,
     parent_expr: &'tcx hir::Expr,
-    ty: impl std::fmt::Debug,
+    ty: &str,
 ) -> bool {
     // We only want to handle exclusive (`..`) ranges,
     // which are represented as `ExprKind::Struct`.
@@ -83,15 +83,15 @@ fn lint_overflowing_range_endpoint<'a, 'tcx>(
             let mut err = cx.struct_span_lint(
                 OVERFLOWING_LITERALS,
                 parent_expr.span,
-                &format!("range endpoint is out of range for `{:?}`", ty),
+                &format!("range endpoint is out of range for `{}`", ty),
             );
             if let Ok(start) = cx.sess().source_map().span_to_snippet(eps[0].span) {
                 use ast::{LitKind, LitIntType};
                 // We need to preserve the literal's suffix,
                 // as it may determine typing information.
                 let suffix = match lit.node {
-                    LitKind::Int(_, LitIntType::Signed(s)) => format!("{}", s),
-                    LitKind::Int(_, LitIntType::Unsigned(s)) => format!("{}", s),
+                    LitKind::Int(_, LitIntType::Signed(s)) => format!("{}", s.name_str()),
+                    LitKind::Int(_, LitIntType::Unsigned(s)) => format!("{}", s.name_str()),
                     LitKind::Int(_, LitIntType::Unsuffixed) => "".to_owned(),
                     _ => bug!(),
                 };
@@ -161,11 +161,11 @@ fn report_bin_hex_error(
     let (t, actually) = match ty {
         attr::IntType::SignedInt(t) => {
             let actually = sign_extend(val, size) as i128;
-            (format!("{:?}", t), actually.to_string())
+            (t.name_str(), actually.to_string())
         }
         attr::IntType::UnsignedInt(t) => {
             let actually = truncate(val, size);
-            (format!("{:?}", t), actually.to_string())
+            (t.name_str(), actually.to_string())
         }
     };
     let mut err = cx.struct_span_lint(
@@ -204,7 +204,7 @@ fn report_bin_hex_error(
 //  - `uX` => `uY`
 //
 // No suggestion for: `isize`, `usize`.
-fn get_type_suggestion(t: Ty<'_>, val: u128, negative: bool) -> Option<String> {
+fn get_type_suggestion(t: Ty<'_>, val: u128, negative: bool) -> Option<&'static str> {
     use syntax::ast::IntTy::*;
     use syntax::ast::UintTy::*;
     macro_rules! find_fit {
@@ -215,10 +215,10 @@ fn get_type_suggestion(t: Ty<'_>, val: u128, negative: bool) -> Option<String> {
                 match $ty {
                     $($type => {
                         $(if !negative && val <= uint_ty_range($utypes).1 {
-                            return Some(format!("{:?}", $utypes))
+                            return Some($utypes.name_str())
                         })*
                         $(if val <= int_ty_range($itypes).1 as u128 + _neg {
-                            return Some(format!("{:?}", $itypes))
+                            return Some($itypes.name_str())
                         })*
                         None
                     },)+
@@ -281,7 +281,7 @@ fn lint_int_literal<'a, 'tcx>(
         if let Node::Expr(par_e) = cx.tcx.hir().get(par_id) {
             if let hir::ExprKind::Struct(..) = par_e.kind {
                 if is_range_literal(cx.sess(), par_e)
-                    && lint_overflowing_range_endpoint(cx, lit, v, max, e, par_e, t)
+                    && lint_overflowing_range_endpoint(cx, lit, v, max, e, par_e, t.name_str())
                 {
                     // The overflowing literal lint was overridden.
                     return;
@@ -292,7 +292,7 @@ fn lint_int_literal<'a, 'tcx>(
         cx.span_lint(
             OVERFLOWING_LITERALS,
             e.span,
-            &format!("literal out of range for `{:?}`", t),
+            &format!("literal out of range for `{}`", t.name_str()),
         );
     }
 }
@@ -338,6 +338,7 @@ fn lint_uint_literal<'a, 'tcx>(
                 }
                 hir::ExprKind::Struct(..)
                     if is_range_literal(cx.sess(), par_e) => {
+                        let t = t.name_str();
                         if lint_overflowing_range_endpoint(cx, lit, lit_val, max, e, par_e, t) {
                             // The overflowing literal lint was overridden.
                             return;
@@ -353,7 +354,7 @@ fn lint_uint_literal<'a, 'tcx>(
         cx.span_lint(
             OVERFLOWING_LITERALS,
             e.span,
-            &format!("literal out of range for `{:?}`", t),
+            &format!("literal out of range for `{}`", t.name_str()),
         );
     }
 }
@@ -379,8 +380,7 @@ fn lint_literal<'a, 'tcx>(
         }
         ty::Float(t) => {
             let is_infinite = match lit.node {
-                ast::LitKind::Float(v, _) |
-                ast::LitKind::FloatUnsuffixed(v) => {
+                ast::LitKind::Float(v, _) => {
                     match t {
                         ast::FloatTy::F32 => v.as_str().parse().map(f32::is_infinite),
                         ast::FloatTy::F64 => v.as_str().parse().map(f64::is_infinite),
@@ -389,9 +389,11 @@ fn lint_literal<'a, 'tcx>(
                 _ => bug!(),
             };
             if is_infinite == Ok(true) {
-                cx.span_lint(OVERFLOWING_LITERALS,
-                             e.span,
-                             &format!("literal out of range for `{:?}`", t));
+                cx.span_lint(
+                    OVERFLOWING_LITERALS,
+                    e.span,
+                    &format!("literal out of range for `{}`", t.name_str()),
+                );
             }
         }
         _ => {}
diff --git a/src/librustc_mir/hair/constant.rs b/src/librustc_mir/hair/constant.rs
index 956716f8ceaf7..b9e75a576cad8 100644
--- a/src/librustc_mir/hair/constant.rs
+++ b/src/librustc_mir/hair/constant.rs
@@ -45,10 +45,7 @@ crate fn lit_to_const<'tcx>(
             trunc(n as u128)?
         },
         LitKind::Int(n, _) => trunc(n)?,
-        LitKind::Float(n, fty) => {
-            parse_float(n, fty, neg).map_err(|_| LitToConstError::UnparseableFloat)?
-        }
-        LitKind::FloatUnsuffixed(n) => {
+        LitKind::Float(n, _) => {
             let fty = match ty.kind {
                 ty::Float(fty) => fty,
                 _ => bug!()
diff --git a/src/librustc_save_analysis/Cargo.toml b/src/librustc_save_analysis/Cargo.toml
index b89c83d630b7d..2d93585e50ee4 100644
--- a/src/librustc_save_analysis/Cargo.toml
+++ b/src/librustc_save_analysis/Cargo.toml
@@ -13,7 +13,6 @@ log = "0.4"
 rustc = { path = "../librustc" }
 rustc_data_structures = { path = "../librustc_data_structures" }
 rustc_codegen_utils = { path = "../librustc_codegen_utils" }
-rustc_target = { path = "../librustc_target" }
 serde_json = "1"
 syntax = { path = "../libsyntax" }
 syntax_pos = { path = "../libsyntax_pos" }
diff --git a/src/librustc_target/abi/mod.rs b/src/librustc_target/abi/mod.rs
index fde5c5bed4d91..e58caed0c99dd 100644
--- a/src/librustc_target/abi/mod.rs
+++ b/src/librustc_target/abi/mod.rs
@@ -3,11 +3,9 @@ pub use Primitive::*;
 
 use crate::spec::Target;
 
-use std::fmt;
 use std::ops::{Add, Deref, Sub, Mul, AddAssign, Range, RangeInclusive};
 
 use rustc_index::vec::{Idx, IndexVec};
-use syntax_pos::symbol::{sym, Symbol};
 use syntax_pos::Span;
 
 pub mod call;
@@ -534,49 +532,13 @@ impl Integer {
     }
 }
 
-
 #[derive(Clone, PartialEq, Eq, RustcEncodable, RustcDecodable, Hash, Copy,
-         PartialOrd, Ord)]
+         PartialOrd, Ord, Debug)]
 pub enum FloatTy {
     F32,
     F64,
 }
 
-impl fmt::Debug for FloatTy {
-    fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
-        fmt::Display::fmt(self, f)
-    }
-}
-
-impl fmt::Display for FloatTy {
-    fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
-        write!(f, "{}", self.ty_to_string())
-    }
-}
-
-impl FloatTy {
-    pub fn ty_to_string(self) -> &'static str {
-        match self {
-            FloatTy::F32 => "f32",
-            FloatTy::F64 => "f64",
-        }
-    }
-
-    pub fn to_symbol(self) -> Symbol {
-        match self {
-            FloatTy::F32 => sym::f32,
-            FloatTy::F64 => sym::f64,
-        }
-    }
-
-    pub fn bit_width(self) -> usize {
-        match self {
-            FloatTy::F32 => 32,
-            FloatTy::F64 => 64,
-        }
-    }
-}
-
 /// Fundamental unit of memory access and layout.
 #[derive(Copy, Clone, PartialEq, Eq, Hash, Debug)]
 pub enum Primitive {
diff --git a/src/librustc_typeck/check/mod.rs b/src/librustc_typeck/check/mod.rs
index f7132cd868aac..2dadda52bed2d 100644
--- a/src/librustc_typeck/check/mod.rs
+++ b/src/librustc_typeck/check/mod.rs
@@ -3661,8 +3661,8 @@ impl<'a, 'tcx> FnCtxt<'a, 'tcx> {
                 });
                 opt_ty.unwrap_or_else(|| self.next_int_var())
             }
-            ast::LitKind::Float(_, t) => tcx.mk_mach_float(t),
-            ast::LitKind::FloatUnsuffixed(_) => {
+            ast::LitKind::Float(_, ast::LitFloatType::Suffixed(t)) => tcx.mk_mach_float(t),
+            ast::LitKind::Float(_, ast::LitFloatType::Unsuffixed) => {
                 let opt_ty = expected.to_option(self).and_then(|ty| {
                     match ty.kind {
                         ty::Float(_) => Some(ty),
diff --git a/src/libsyntax/Cargo.toml b/src/libsyntax/Cargo.toml
index 3ce47e6a7b8cd..7d094e8d71356 100644
--- a/src/libsyntax/Cargo.toml
+++ b/src/libsyntax/Cargo.toml
@@ -20,5 +20,4 @@ errors = { path = "../librustc_errors", package = "rustc_errors" }
 rustc_data_structures = { path = "../librustc_data_structures" }
 rustc_index = { path = "../librustc_index" }
 rustc_lexer = { path = "../librustc_lexer" }
-rustc_target = { path = "../librustc_target" }
 smallvec = { version = "0.6.7", features = ["union", "may_dangle"] }
diff --git a/src/libsyntax/ast.rs b/src/libsyntax/ast.rs
index 8ad1d859f3d04..d508b7c7a44f7 100644
--- a/src/libsyntax/ast.rs
+++ b/src/libsyntax/ast.rs
@@ -22,7 +22,6 @@ pub use GenericArgs::*;
 pub use UnsafeSource::*;
 pub use crate::util::parser::ExprPrecedence;
 
-pub use rustc_target::abi::FloatTy;
 pub use syntax_pos::symbol::{Ident, Symbol as Name};
 
 use crate::parse::token::{self, DelimToken};
@@ -1400,7 +1399,7 @@ pub struct Lit {
 
 // Clippy uses Hash and PartialEq
 /// Type of the integer literal based on provided suffix.
-#[derive(Clone, RustcEncodable, RustcDecodable, Debug, Copy, Hash, PartialEq)]
+#[derive(Clone, Copy, RustcEncodable, RustcDecodable, Debug, Hash, PartialEq)]
 pub enum LitIntType {
     /// e.g. `42_i32`.
     Signed(IntTy),
@@ -1410,6 +1409,15 @@ pub enum LitIntType {
     Unsuffixed,
 }
 
+/// Type of the float literal based on provided suffix.
+#[derive(Clone, Copy, RustcEncodable, RustcDecodable, Debug, Hash, PartialEq)]
+pub enum LitFloatType {
+    /// A float literal with a suffix (`1f32` or `1E10f32`).
+    Suffixed(FloatTy),
+    /// A float literal without a suffix (`1.0 or 1.0E10`).
+    Unsuffixed,
+}
+
 /// Literal kind.
 ///
 /// E.g., `"foo"`, `42`, `12.34`, or `bool`.
@@ -1427,9 +1435,7 @@ pub enum LitKind {
     /// An integer literal (`1`).
     Int(u128, LitIntType),
     /// A float literal (`1f64` or `1E10f64`).
-    Float(Symbol, FloatTy),
-    /// A float literal without a suffix (`1.0 or 1.0E10`).
-    FloatUnsuffixed(Symbol),
+    Float(Symbol, LitFloatType),
     /// A boolean literal.
     Bool(bool),
     /// Placeholder for a literal that wasn't well-formed in some way.
@@ -1456,7 +1462,7 @@ impl LitKind {
     /// Returns `true` if this is a numeric literal.
     pub fn is_numeric(&self) -> bool {
         match *self {
-            LitKind::Int(..) | LitKind::Float(..) | LitKind::FloatUnsuffixed(..) => true,
+            LitKind::Int(..) | LitKind::Float(..) => true,
             _ => false,
         }
     }
@@ -1473,14 +1479,14 @@ impl LitKind {
             // suffixed variants
             LitKind::Int(_, LitIntType::Signed(..))
             | LitKind::Int(_, LitIntType::Unsigned(..))
-            | LitKind::Float(..) => true,
+            | LitKind::Float(_, LitFloatType::Suffixed(..)) => true,
             // unsuffixed variants
             LitKind::Str(..)
             | LitKind::ByteStr(..)
             | LitKind::Byte(..)
             | LitKind::Char(..)
             | LitKind::Int(_, LitIntType::Unsuffixed)
-            | LitKind::FloatUnsuffixed(..)
+            | LitKind::Float(_, LitFloatType::Unsuffixed)
             | LitKind::Bool(..)
             | LitKind::Err(..) => false,
         }
@@ -1552,7 +1558,36 @@ pub enum ImplItemKind {
     Macro(Mac),
 }
 
-#[derive(Clone, PartialEq, Eq, PartialOrd, Ord, Hash, RustcEncodable, RustcDecodable, Copy)]
+#[derive(Clone, Copy, PartialEq, Eq, PartialOrd, Ord, Hash, RustcEncodable, RustcDecodable, Debug)]
+pub enum FloatTy {
+    F32,
+    F64,
+}
+
+impl FloatTy {
+    pub fn name_str(self) -> &'static str {
+        match self {
+            FloatTy::F32 => "f32",
+            FloatTy::F64 => "f64",
+        }
+    }
+
+    pub fn name(self) -> Symbol {
+        match self {
+            FloatTy::F32 => sym::f32,
+            FloatTy::F64 => sym::f64,
+        }
+    }
+
+    pub fn bit_width(self) -> usize {
+        match self {
+            FloatTy::F32 => 32,
+            FloatTy::F64 => 64,
+        }
+    }
+}
+
+#[derive(Clone, Copy, PartialEq, Eq, PartialOrd, Ord, Hash, RustcEncodable, RustcDecodable, Debug)]
 pub enum IntTy {
     Isize,
     I8,
@@ -1562,20 +1597,8 @@ pub enum IntTy {
     I128,
 }
 
-impl fmt::Debug for IntTy {
-    fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
-        fmt::Display::fmt(self, f)
-    }
-}
-
-impl fmt::Display for IntTy {
-    fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
-        write!(f, "{}", self.ty_to_string())
-    }
-}
-
 impl IntTy {
-    pub fn ty_to_string(&self) -> &'static str {
+    pub fn name_str(&self) -> &'static str {
         match *self {
             IntTy::Isize => "isize",
             IntTy::I8 => "i8",
@@ -1586,7 +1609,7 @@ impl IntTy {
         }
     }
 
-    pub fn to_symbol(&self) -> Symbol {
+    pub fn name(&self) -> Symbol {
         match *self {
             IntTy::Isize => sym::isize,
             IntTy::I8 => sym::i8,
@@ -1601,7 +1624,7 @@ impl IntTy {
         // Cast to a `u128` so we can correctly print `INT128_MIN`. All integral types
         // are parsed as `u128`, so we wouldn't want to print an extra negative
         // sign.
-        format!("{}{}", val as u128, self.ty_to_string())
+        format!("{}{}", val as u128, self.name_str())
     }
 
     pub fn bit_width(&self) -> Option<usize> {
@@ -1616,7 +1639,7 @@ impl IntTy {
     }
 }
 
-#[derive(Clone, PartialEq, Eq, PartialOrd, Ord, Hash, RustcEncodable, RustcDecodable, Copy)]
+#[derive(Clone, PartialEq, Eq, PartialOrd, Ord, Hash, RustcEncodable, RustcDecodable, Copy, Debug)]
 pub enum UintTy {
     Usize,
     U8,
@@ -1627,7 +1650,7 @@ pub enum UintTy {
 }
 
 impl UintTy {
-    pub fn ty_to_string(&self) -> &'static str {
+    pub fn name_str(&self) -> &'static str {
         match *self {
             UintTy::Usize => "usize",
             UintTy::U8 => "u8",
@@ -1638,7 +1661,7 @@ impl UintTy {
         }
     }
 
-    pub fn to_symbol(&self) -> Symbol {
+    pub fn name(&self) -> Symbol {
         match *self {
             UintTy::Usize => sym::usize,
             UintTy::U8 => sym::u8,
@@ -1650,7 +1673,7 @@ impl UintTy {
     }
 
     pub fn val_to_string(&self, val: u128) -> String {
-        format!("{}{}", val, self.ty_to_string())
+        format!("{}{}", val, self.name_str())
     }
 
     pub fn bit_width(&self) -> Option<usize> {
@@ -1665,18 +1688,6 @@ impl UintTy {
     }
 }
 
-impl fmt::Debug for UintTy {
-    fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
-        fmt::Display::fmt(self, f)
-    }
-}
-
-impl fmt::Display for UintTy {
-    fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
-        write!(f, "{}", self.ty_to_string())
-    }
-}
-
 /// A constraint on an associated type (e.g., `A = Bar` in `Foo<A = Bar>` or
 /// `A: TraitA + TraitB` in `Foo<A: TraitA + TraitB>`).
 #[derive(Clone, RustcEncodable, RustcDecodable, Debug)]
diff --git a/src/libsyntax/parse/literal.rs b/src/libsyntax/parse/literal.rs
index 7952e293a532d..f6a53efd22478 100644
--- a/src/libsyntax/parse/literal.rs
+++ b/src/libsyntax/parse/literal.rs
@@ -157,17 +157,18 @@ impl LitKind {
             }
             LitKind::Int(n, ty) => {
                 let suffix = match ty {
-                    ast::LitIntType::Unsigned(ty) => Some(ty.to_symbol()),
-                    ast::LitIntType::Signed(ty) => Some(ty.to_symbol()),
+                    ast::LitIntType::Unsigned(ty) => Some(ty.name()),
+                    ast::LitIntType::Signed(ty) => Some(ty.name()),
                     ast::LitIntType::Unsuffixed => None,
                 };
                 (token::Integer, sym::integer(n), suffix)
             }
             LitKind::Float(symbol, ty) => {
-                (token::Float, symbol, Some(ty.to_symbol()))
-            }
-            LitKind::FloatUnsuffixed(symbol) => {
-                (token::Float, symbol, None)
+                let suffix = match ty {
+                    ast::LitFloatType::Suffixed(ty) => Some(ty.name()),
+                    ast::LitFloatType::Unsuffixed => None,
+                };
+                (token::Float, symbol, suffix)
             }
             LitKind::Bool(value) => {
                 let symbol = if value { kw::True } else { kw::False };
@@ -244,12 +245,12 @@ fn filtered_float_lit(symbol: Symbol, suffix: Option<Symbol>, base: u32)
         return Err(LitError::NonDecimalFloat(base));
     }
     Ok(match suffix {
-        Some(suf) => match suf {
-            sym::f32 => LitKind::Float(symbol, ast::FloatTy::F32),
-            sym::f64 => LitKind::Float(symbol, ast::FloatTy::F64),
+        Some(suf) => LitKind::Float(symbol, ast::LitFloatType::Suffixed(match suf {
+            sym::f32 => ast::FloatTy::F32,
+            sym::f64 => ast::FloatTy::F64,
             _ => return Err(LitError::InvalidFloatSuffix),
-        }
-        None => LitKind::FloatUnsuffixed(symbol)
+        })),
+        None => LitKind::Float(symbol, ast::LitFloatType::Unsuffixed)
     })
 }
 
diff --git a/src/libsyntax_expand/Cargo.toml b/src/libsyntax_expand/Cargo.toml
index f063753f59943..046a50d3c88ea 100644
--- a/src/libsyntax_expand/Cargo.toml
+++ b/src/libsyntax_expand/Cargo.toml
@@ -21,6 +21,5 @@ errors = { path = "../librustc_errors", package = "rustc_errors" }
 rustc_data_structures = { path = "../librustc_data_structures" }
 rustc_index = { path = "../librustc_index" }
 rustc_lexer = { path = "../librustc_lexer" }
-rustc_target = { path = "../librustc_target" }
 smallvec = { version = "0.6.7", features = ["union", "may_dangle"] }
 syntax = { path = "../libsyntax" }
diff --git a/src/libsyntax_ext/concat.rs b/src/libsyntax_ext/concat.rs
index 47bade698a80a..4bf13f3771102 100644
--- a/src/libsyntax_ext/concat.rs
+++ b/src/libsyntax_ext/concat.rs
@@ -21,8 +21,7 @@ pub fn expand_concat(
         match e.kind {
             ast::ExprKind::Lit(ref lit) => match lit.kind {
                 ast::LitKind::Str(ref s, _)
-                | ast::LitKind::Float(ref s, _)
-                | ast::LitKind::FloatUnsuffixed(ref s) => {
+                | ast::LitKind::Float(ref s, _) => {
                     accumulator.push_str(&s.as_str());
                 }
                 ast::LitKind::Char(c) => {