Merge from rustc

4 files changed, 27 insertions, 10 deletions

diff --git a/compiler/rustc_parse/src/parser/expr.rs b/compiler/rustc_parse/src/parser/expr.rs
index 9f748e2a3fe..e36a648e203 100644
--- a/compiler/rustc_parse/src/parser/expr.rs
+++ b/compiler/rustc_parse/src/parser/expr.rs
@@ -3288,7 +3288,7 @@ impl<'a> Parser<'a> {
                         } else {
                             Applicability::MaybeIncorrect
                         };
-                        err.span_suggestion_verbose(sugg_sp, msg, "=> ".to_string(), applicability);
+                        err.span_suggestion_verbose(sugg_sp, msg, "=> ", applicability);
                     }
                 }
                 err
diff --git a/compiler/rustc_parse/src/parser/generics.rs b/compiler/rustc_parse/src/parser/generics.rs
index 48cf04f7790..e059e707491 100644
--- a/compiler/rustc_parse/src/parser/generics.rs
+++ b/compiler/rustc_parse/src/parser/generics.rs
@@ -148,7 +148,7 @@ impl<'a> Parser<'a> {
             .with_span_suggestion_verbose(
                 mistyped_const_ident.span,
                 "use the `const` keyword",
-                kw::Const.as_str(),
+                kw::Const,
                 Applicability::MachineApplicable,
             )
             .emit();
diff --git a/compiler/rustc_parse/src/parser/item.rs b/compiler/rustc_parse/src/parser/item.rs
index 9a77643f951..8050b34956c 100644
--- a/compiler/rustc_parse/src/parser/item.rs
+++ b/compiler/rustc_parse/src/parser/item.rs
@@ -1453,7 +1453,7 @@ impl<'a> Parser<'a> {
                                 err.span_suggestion_verbose(
                                     prev_span,
                                     "perhaps you meant to use `struct` here",
-                                    "struct".to_string(),
+                                    "struct",
                                     Applicability::MaybeIncorrect,
                                 );
                             }
diff --git a/compiler/rustc_parse/src/parser/ty.rs b/compiler/rustc_parse/src/parser/ty.rs
index a4fb92c67ac..5fe54a536a7 100644
--- a/compiler/rustc_parse/src/parser/ty.rs
+++ b/compiler/rustc_parse/src/parser/ty.rs
@@ -3,19 +3,18 @@ use super::{Parser, PathStyle, TokenType};
 use crate::errors::{
     self, DynAfterMut, ExpectedFnPathFoundFnKeyword, ExpectedMutOrConstInRawPointerType,
     FnPointerCannotBeAsync, FnPointerCannotBeConst, FnPtrWithGenerics, FnPtrWithGenericsSugg,
-    InvalidDynKeyword, LifetimeAfterMut, NeedPlusAfterTraitObjectLifetime, NestedCVariadicType,
-    ReturnTypesUseThinArrow,
+    HelpUseLatestEdition, InvalidDynKeyword, LifetimeAfterMut, NeedPlusAfterTraitObjectLifetime,
+    NestedCVariadicType, ReturnTypesUseThinArrow,
 };
 use crate::{maybe_recover_from_interpolated_ty_qpath, maybe_whole};
 
-use ast::DUMMY_NODE_ID;
 use rustc_ast::ptr::P;
 use rustc_ast::token::{self, Delimiter, Token, TokenKind};
 use rustc_ast::util::case::Case;
 use rustc_ast::{
-    self as ast, BareFnTy, BoundConstness, BoundPolarity, FnRetTy, GenericBound, GenericBounds,
-    GenericParam, Generics, Lifetime, MacCall, MutTy, Mutability, PolyTraitRef,
-    TraitBoundModifiers, TraitObjectSyntax, Ty, TyKind,
+    self as ast, BareFnTy, BoundAsyncness, BoundConstness, BoundPolarity, FnRetTy, GenericBound,
+    GenericBounds, GenericParam, Generics, Lifetime, MacCall, MutTy, Mutability, PolyTraitRef,
+    TraitBoundModifiers, TraitObjectSyntax, Ty, TyKind, DUMMY_NODE_ID,
 };
 use rustc_errors::{Applicability, PResult};
 use rustc_span::symbol::{kw, sym, Ident};
@@ -880,6 +879,24 @@ impl<'a> Parser<'a> {
             BoundConstness::Never
         };
 
+        let asyncness = if self.token.span.at_least_rust_2018() && self.eat_keyword(kw::Async) {
+            self.sess.gated_spans.gate(sym::async_closure, self.prev_token.span);
+            BoundAsyncness::Async(self.prev_token.span)
+        } else if self.may_recover()
+            && self.token.span.is_rust_2015()
+            && self.is_kw_followed_by_ident(kw::Async)
+        {
+            self.bump(); // eat `async`
+            self.dcx().emit_err(errors::AsyncBoundModifierIn2015 {
+                span: self.prev_token.span,
+                help: HelpUseLatestEdition::new(),
+            });
+            self.sess.gated_spans.gate(sym::async_closure, self.prev_token.span);
+            BoundAsyncness::Async(self.prev_token.span)
+        } else {
+            BoundAsyncness::Normal
+        };
+
         let polarity = if self.eat(&token::Question) {
             BoundPolarity::Maybe(self.prev_token.span)
         } else if self.eat(&token::Not) {
@@ -889,7 +906,7 @@ impl<'a> Parser<'a> {
             BoundPolarity::Positive
         };
 
-        Ok(TraitBoundModifiers { constness, polarity })
+        Ok(TraitBoundModifiers { constness, asyncness, polarity })
     }
 
     /// Parses a type bound according to: