From 7ae5c7f32dfc85c0e57949dee1c54bd1c6586e37 Mon Sep 17 00:00:00 2001 From: Nicholas Nethercote Date: Wed, 9 Apr 2025 14:16:22 +1000 Subject: Avoid an empty trait name in impl blocks. `resolve_ident_in_lexical_scope` checks for an empty name. Why is this necessary? Because `parse_item_impl` can produce an `impl` block with an empty trait name in some cases. This is pretty gross and very non-obvious. This commit avoids the use of the empty trait name. In one case the trait name is instead pulled from `TyKind::ImplTrait`, which prevents the output for `tests/ui/impl-trait/extra-impl-in-trait-impl.rs` from changing. In the other case we just fail the parse and don't try to recover. I think losing error recovery in this obscure case is worth the code cleanup. This change affects `tests/ui/parser/impl-parsing.rs`, which is split in two, and the obsolete `..` syntax cases are removed (they are tested elsewhere). --- compiler/rustc_parse/src/parser/item.rs | 9 +++++---- 1 file changed, 5 insertions(+), 4 deletions(-) (limited to 'compiler/rustc_parse/src/parser') diff --git a/compiler/rustc_parse/src/parser/item.rs b/compiler/rustc_parse/src/parser/item.rs index 915a30e5469..06501816340 100644 --- a/compiler/rustc_parse/src/parser/item.rs +++ b/compiler/rustc_parse/src/parser/item.rs @@ -649,6 +649,7 @@ impl<'a> Parser<'a> { other => { if let TyKind::ImplTrait(_, bounds) = other && let [bound] = bounds.as_slice() + && let GenericBound::Trait(poly_trait_ref) = bound { // Suggest removing extra `impl` keyword: // `impl impl Default for Wrapper` @@ -658,12 +659,12 @@ impl<'a> Parser<'a> { extra_impl_kw, impl_trait_span: ty_first.span, }); + poly_trait_ref.trait_ref.path.clone() } else { - self.dcx().emit_err(errors::ExpectedTraitInTraitImplFoundType { - span: ty_first.span, - }); + return Err(self.dcx().create_err( + errors::ExpectedTraitInTraitImplFoundType { span: ty_first.span }, + )); } - ast::Path::from_ident(Ident::new(kw::Empty, ty_first.span)) } }; let trait_ref = TraitRef { path, ref_id: ty_first.id }; -- cgit 1.4.1-3-g733a5