Add lang item for AsyncFnKindHelper::Upvars

compiler/rustc_trait_selection/src/solve/assembly/structural_traits.rs

@@ -9,7 +9,6 @@ use rustc_macros::{TypeFoldable, TypeVisitable};
 use rustc_middle::bug;
 use rustc_middle::traits::solve::Goal;
 use rustc_middle::ty::{self, Ty, TyCtxt, TypeFoldable, TypeFolder, TypeSuperFoldable, Upcast};
-use rustc_span::sym;
 
 use crate::solve::EvalCtxt;
 
@@ -582,13 +581,7 @@ fn coroutine_closure_to_ambiguous_coroutine<'tcx>(
     args: ty::CoroutineClosureArgs<'tcx>,
     sig: ty::CoroutineClosureSignature<'tcx>,
 ) -> Ty<'tcx> {
-    let async_fn_kind_trait_def_id = tcx.require_lang_item(LangItem::AsyncFnKindHelper, None);
-    let upvars_projection_def_id = tcx
-        .associated_items(async_fn_kind_trait_def_id)
-        .filter_by_name_unhygienic(sym::Upvars)
-        .next()
-        .unwrap()
-        .def_id;
+    let upvars_projection_def_id = tcx.require_lang_item(LangItem::AsyncFnKindUpvars, None);
     let tupled_upvars_ty = Ty::new_projection(
         tcx,
         upvars_projection_def_id,