diff options
Diffstat (limited to 'compiler')
| -rw-r--r-- | compiler/rustc_ast_lowering/src/lib.rs | 31 | ||||
| -rw-r--r-- | compiler/rustc_typeck/src/check/closure.rs | 12 |
2 files changed, 27 insertions, 16 deletions
diff --git a/compiler/rustc_ast_lowering/src/lib.rs b/compiler/rustc_ast_lowering/src/lib.rs index 8fa2c593193..e8201c0ddca 100644 --- a/compiler/rustc_ast_lowering/src/lib.rs +++ b/compiler/rustc_ast_lowering/src/lib.rs @@ -1960,8 +1960,13 @@ impl<'a, 'hir> LoweringContext<'a, 'hir> { // // Then, we will create `fn foo(..) -> Foo<'_, '_>`, and // hence the elision takes place at the fn site. - let future_bound = - this.lower_async_fn_output_type_to_future_bound(output, fn_def_id, span); + let future_bound = this.lower_async_fn_output_type_to_future_bound( + output, + span, + ImplTraitContext::ReturnPositionOpaqueTy { + origin: hir::OpaqueTyOrigin::FnReturn(fn_def_id), + }, + ); let generic_params = this.arena.alloc_from_iter(collected_lifetimes.iter().map( |&(new_node_id, lifetime, _)| { @@ -2064,17 +2069,16 @@ impl<'a, 'hir> LoweringContext<'a, 'hir> { fn_node_id: NodeId, opaque_ty_node_id: NodeId, ) -> hir::FnRetTy<'hir> { - let span = output.span(); - - let opaque_ty_span = self.mark_span_with_reason(DesugaringKind::Async, span, None); - - let fn_def_id = self.local_def_id(fn_node_id); - let kind = self.lower_impl_trait_in_trait(output.span(), opaque_ty_node_id, |lctx| { - let bound = - lctx.lower_async_fn_output_type_to_future_bound(output, fn_def_id, output.span()); + let bound = lctx.lower_async_fn_output_type_to_future_bound( + output, + output.span(), + ImplTraitContext::Disallowed(ImplTraitPosition::TraitReturn), + ); arena_vec![lctx; bound] }); + + let opaque_ty_span = self.mark_span_with_reason(DesugaringKind::Async, output.span(), None); let opaque_ty = self.ty(opaque_ty_span, kind); hir::FnRetTy::Return(self.arena.alloc(opaque_ty)) } @@ -2083,8 +2087,8 @@ impl<'a, 'hir> LoweringContext<'a, 'hir> { fn lower_async_fn_output_type_to_future_bound( &mut self, output: &FnRetTy, - fn_def_id: LocalDefId, span: Span, + mut nested_impl_trait_context: ImplTraitContext, ) -> hir::GenericBound<'hir> { // Compute the `T` in `Future<Output = T>` from the return type. let output_ty = match output { @@ -2092,10 +2096,7 @@ impl<'a, 'hir> LoweringContext<'a, 'hir> { // Not `OpaqueTyOrigin::AsyncFn`: that's only used for the // `impl Future` opaque type that `async fn` implicitly // generates. - let mut context = ImplTraitContext::ReturnPositionOpaqueTy { - origin: hir::OpaqueTyOrigin::FnReturn(fn_def_id), - }; - self.lower_ty(ty, &mut context) + self.lower_ty(ty, &mut nested_impl_trait_context) } FnRetTy::Default(ret_ty_span) => self.arena.alloc(self.ty_tup(*ret_ty_span, &[])), }; diff --git a/compiler/rustc_typeck/src/check/closure.rs b/compiler/rustc_typeck/src/check/closure.rs index bc3fec6e7d6..55cbaf71e7c 100644 --- a/compiler/rustc_typeck/src/check/closure.rs +++ b/compiler/rustc_typeck/src/check/closure.rs @@ -4,6 +4,7 @@ use super::{check_fn, Expectation, FnCtxt, GeneratorTypes}; use crate::astconv::AstConv; use crate::rustc_middle::ty::subst::Subst; +use hir::def::DefKind; use rustc_hir as hir; use rustc_hir::def_id::DefId; use rustc_hir::lang_items::LangItem; @@ -680,9 +681,18 @@ impl<'a, 'tcx> FnCtxt<'a, 'tcx> { .map(|e| e.map_bound(|e| *e).transpose_tuple2()) .find_map(|(p, s)| get_future_output(p.subst(self.tcx, substs), s.0))?, ty::Error(_) => return None, + ty::Projection(proj) + if self.tcx.def_kind(proj.item_def_id) == DefKind::ImplTraitPlaceholder => + { + self.tcx + .bound_explicit_item_bounds(proj.item_def_id) + .transpose_iter() + .map(|e| e.map_bound(|e| *e).transpose_tuple2()) + .find_map(|(p, s)| get_future_output(p.subst(self.tcx, proj.substs), s.0))? + } _ => span_bug!( self.tcx.def_span(expr_def_id), - "async fn generator return type not an inference variable" + "async fn generator return type not an inference variable: {ret_ty}" ), }; |