Generator return doesn't need to be a lang item

Author: compiler-errors

compiler/rustc_hir/src/lang_items.rs

@@ -238,7 +238,6 @@ language_item_table! {
     Future,                  sym::future_trait,        future_trait,               Target::Trait,          GenericRequirement::Exact(0);
     GeneratorState,          sym::generator_state,     gen_state,                  Target::Enum,           GenericRequirement::None;
     Generator,               sym::generator,           gen_trait,                  Target::Trait,          GenericRequirement::Minimum(1);
-    GeneratorReturn,         sym::generator_return,    generator_return,           Target::AssocTy,        GenericRequirement::None;
     Unpin,                   sym::unpin,               unpin_trait,                Target::Trait,          GenericRequirement::None;
     Pin,                     sym::pin,                 pin_type,                   Target::Struct,         GenericRequirement::None;
 

compiler/rustc_middle/src/ty/print/pretty.rs

@@ -916,8 +916,10 @@ pub trait PrettyPrinter<'tcx>:
                         // Skip printing `<[generator@] as Generator<_>>::Return` from async blocks,
                         // unless we can find out what generator return type it comes from.
                         let term = if let Some(ty) = term.skip_binder().ty()
-                            && let ty::Projection(ty::ProjectionTy { item_def_id, substs }) = ty.kind()
-                            && Some(*item_def_id) == tcx.lang_items().generator_return()
+                            && let ty::Projection(proj) = ty.kind()
+                            && let assoc = tcx.associated_item(proj.item_def_id)
+                            && assoc.trait_container(tcx) == tcx.lang_items().gen_trait()
+                            && assoc.name == rustc_span::sym::Return
                         {
                             if let ty::Generator(_, substs, _) = substs.type_at(0).kind() {
                                 let return_ty = substs.as_generator().return_ty();

compiler/rustc_span/src/symbol.rs

@@ -763,7 +763,6 @@ symbols! {
         gen_future,
         gen_kill,
         generator,
-        generator_return,
         generator_state,
         generators,
         generic_arg_infer,

library/core/src/ops/generator.rs

@@ -83,7 +83,7 @@ pub trait Generator<R = ()> {
     /// `return` statement or implicitly as the last expression of a generator
     /// literal. For example futures would use this as `Result<T, E>` as it
     /// represents a completed future.
-    #[lang = "generator_return"]
+    #[cfg_attr(bootstrap, lang = "generator_return")]
     type Return;
 
     /// Resumes the execution of this generator.