diff options
Diffstat (limited to 'compiler/rustc_ast_lowering/src')
| -rw-r--r-- | compiler/rustc_ast_lowering/src/lib.rs | 24 |
1 files changed, 11 insertions, 13 deletions
diff --git a/compiler/rustc_ast_lowering/src/lib.rs b/compiler/rustc_ast_lowering/src/lib.rs index dc427f607f5..4ef9c7607be 100644 --- a/compiler/rustc_ast_lowering/src/lib.rs +++ b/compiler/rustc_ast_lowering/src/lib.rs @@ -1092,24 +1092,22 @@ impl<'a, 'hir> LoweringContext<'a, 'hir> { // Piggy-back on the `impl Trait` context to figure out the correct behavior. let desugar_kind = match itctx { - // We are in the return position: - // - // fn foo() -> impl Iterator<Item: Debug> - // - // so desugar to - // - // fn foo() -> impl Iterator<Item = impl Debug> - ImplTraitContext::ReturnPositionOpaqueTy { .. } - | ImplTraitContext::TypeAliasesOpaqueTy { .. } => DesugarKind::ImplTrait, - - // We are in the argument position, but within a dyn type: + // in an argument, RPIT, or TAIT, if we are within a dyn type: // // fn foo(x: dyn Iterator<Item: Debug>) // - // so desugar to + // then desugar to: // // fn foo(x: dyn Iterator<Item = impl Debug>) - ImplTraitContext::Universal if self.is_in_dyn_type => DesugarKind::ImplTrait, + // + // This is because dyn traits must have all of their associated types specified. + ImplTraitContext::ReturnPositionOpaqueTy { .. } + | ImplTraitContext::TypeAliasesOpaqueTy { .. } + | ImplTraitContext::Universal + if self.is_in_dyn_type => + { + DesugarKind::ImplTrait + } ImplTraitContext::Disallowed(position) if self.is_in_dyn_type => { DesugarKind::Error(position) |