From b59090ebe3779732033c7d984e1f8b369798b3a4 Mon Sep 17 00:00:00 2001 From: Arpad Borsos Date: Sat, 19 Nov 2022 18:23:32 +0100 Subject: [PATCH] Lower return type outside async block creation This allows feeding a different output type to async blocks with a different `ImplTraitContext`. --- compiler/rustc_ast_lowering/src/expr.rs | 18 +++++++++--------- 1 file changed, 9 insertions(+), 9 deletions(-) diff --git a/compiler/rustc_ast_lowering/src/expr.rs b/compiler/rustc_ast_lowering/src/expr.rs index eaa5a38388afc..7cb794c2b09ec 100644 --- a/compiler/rustc_ast_lowering/src/expr.rs +++ b/compiler/rustc_ast_lowering/src/expr.rs @@ -588,17 +588,12 @@ impl<'hir> LoweringContext<'_, 'hir> { &mut self, capture_clause: CaptureBy, closure_node_id: NodeId, - ret_ty: Option>, + ret_ty: Option>, span: Span, async_gen_kind: hir::AsyncGeneratorKind, body: impl FnOnce(&mut Self) -> hir::Expr<'hir>, ) -> hir::ExprKind<'hir> { - let output = match ret_ty { - Some(ty) => hir::FnRetTy::Return( - self.lower_ty(&ty, &ImplTraitContext::Disallowed(ImplTraitPosition::AsyncBlock)), - ), - None => hir::FnRetTy::DefaultReturn(self.lower_span(span)), - }; + let output = ret_ty.unwrap_or_else(|| hir::FnRetTy::DefaultReturn(self.lower_span(span))); // Resume argument type. We let the compiler infer this to simplify the lowering. It is // fully constrained by `future::from_generator`. @@ -1003,8 +998,13 @@ impl<'hir> LoweringContext<'_, 'hir> { // Transform `async |x: u8| -> X { ... }` into // `|x: u8| future_from_generator(|| -> X { ... })`. let body_id = this.lower_fn_body(&outer_decl, |this| { - let async_ret_ty = - if let FnRetTy::Ty(ty) = &decl.output { Some(ty.clone()) } else { None }; + let async_ret_ty = if let FnRetTy::Ty(ty) = &decl.output { + let itctx = ImplTraitContext::Disallowed(ImplTraitPosition::AsyncBlock); + Some(hir::FnRetTy::Return(this.lower_ty(&ty, &itctx))) + } else { + None + }; + let async_body = this.make_async_expr( capture_clause, inner_closure_id,