diff options
Diffstat (limited to 'compiler')
| -rw-r--r-- | compiler/rustc_hir_typeck/src/check.rs | 26 |
1 files changed, 23 insertions, 3 deletions
diff --git a/compiler/rustc_hir_typeck/src/check.rs b/compiler/rustc_hir_typeck/src/check.rs index 91c96d6f76f..19b566ff9fa 100644 --- a/compiler/rustc_hir_typeck/src/check.rs +++ b/compiler/rustc_hir_typeck/src/check.rs @@ -59,9 +59,7 @@ pub(super) fn check_fn<'a, 'tcx>( && can_be_coroutine.is_some() { let yield_ty = match kind { - hir::CoroutineKind::Gen(..) - | hir::CoroutineKind::AsyncGen(..) - | hir::CoroutineKind::Coroutine => { + hir::CoroutineKind::Gen(..) | hir::CoroutineKind::Coroutine => { let yield_ty = fcx.next_ty_var(TypeVariableOrigin { kind: TypeVariableOriginKind::TypeInference, span, @@ -69,6 +67,28 @@ pub(super) fn check_fn<'a, 'tcx>( fcx.require_type_is_sized(yield_ty, span, traits::SizedYieldType); yield_ty } + // HACK(-Ztrait-solver=next): In the *old* trait solver, we must eagerly + // guide inference on the yield type so that we can handle `AsyncIterator` + // in this block in projection correctly. In the new trait solver, it is + // not a problem. + hir::CoroutineKind::AsyncGen(..) => { + let yield_ty = fcx.next_ty_var(TypeVariableOrigin { + kind: TypeVariableOriginKind::TypeInference, + span, + }); + fcx.require_type_is_sized(yield_ty, span, traits::SizedYieldType); + + Ty::new_adt( + tcx, + tcx.adt_def(tcx.require_lang_item(hir::LangItem::Poll, Some(span))), + tcx.mk_args(&[Ty::new_adt( + tcx, + tcx.adt_def(tcx.require_lang_item(hir::LangItem::Option, Some(span))), + tcx.mk_args(&[yield_ty.into()]), + ) + .into()]), + ) + } hir::CoroutineKind::Async(..) => Ty::new_unit(tcx), }; |