From 442f39582d2aec5026c8d75079a75f58579059e4 Mon Sep 17 00:00:00 2001 From: =?UTF-8?q?Le=C3=B3n=20Orell=20Valerian=20Liehr?= Date: Sun, 27 Oct 2024 06:21:24 +0100 Subject: [PATCH] Move an impl-Trait check from AST validation to AST lowering --- compiler/rustc_ast_lowering/src/path.rs | 19 ++++- compiler/rustc_ast_passes/messages.ftl | 2 - .../rustc_ast_passes/src/ast_validation.rs | 46 ------------ compiler/rustc_ast_passes/src/errors.rs | 7 -- .../src/error_codes/E0667.md | 6 +- .../src/hir_ty_lowering/mod.rs | 9 --- tests/crashes/126725.rs | 20 ------ tests/ui/impl-trait/impl_trait_projections.rs | 11 ++- .../impl-trait/impl_trait_projections.stderr | 70 +++++-------------- .../in-trait/bad-projection-from-opaque.rs | 22 ++++++ .../bad-projection-from-opaque.stderr | 11 +++ .../issues/issue-57979-impl-trait-in-path.rs | 2 +- .../issue-57979-impl-trait-in-path.stderr | 6 +- 13 files changed, 78 insertions(+), 153 deletions(-) delete mode 100644 tests/crashes/126725.rs create mode 100644 tests/ui/impl-trait/in-trait/bad-projection-from-opaque.rs create mode 100644 tests/ui/impl-trait/in-trait/bad-projection-from-opaque.stderr diff --git a/compiler/rustc_ast_lowering/src/path.rs b/compiler/rustc_ast_lowering/src/path.rs index 258655de486f9..6a0f03c8b3196 100644 --- a/compiler/rustc_ast_lowering/src/path.rs +++ b/compiler/rustc_ast_lowering/src/path.rs @@ -34,7 +34,10 @@ impl<'a, 'hir> LoweringContext<'a, 'hir> { modifiers: Option, ) -> hir::QPath<'hir> { let qself_position = qself.as_ref().map(|q| q.position); - let qself = qself.as_ref().map(|q| self.lower_ty(&q.ty, itctx)); + let qself = qself + .as_ref() + // Reject cases like `::Assoc` and `::Assoc`. + .map(|q| self.lower_ty(&q.ty, ImplTraitContext::Disallowed(ImplTraitPosition::Path))); let partial_res = self.resolver.get_partial_res(id).unwrap_or_else(|| PartialRes::new(Res::Err)); @@ -75,6 +78,16 @@ impl<'a, 'hir> LoweringContext<'a, 'hir> { None }; + // Only permit `impl Trait` in the final segment. E.g., we permit `Option`, + // `option::Option::Xyz` and reject `option::Option::Xyz`. + let itctx = |i| { + if i + 1 == p.segments.len() { + itctx + } else { + ImplTraitContext::Disallowed(ImplTraitPosition::Path) + } + }; + let path_span_lo = p.span.shrink_to_lo(); let proj_start = p.segments.len() - unresolved_segments; let path = self.arena.alloc(hir::Path { @@ -121,7 +134,7 @@ impl<'a, 'hir> LoweringContext<'a, 'hir> { segment, param_mode, generic_args_mode, - itctx, + itctx(i), bound_modifier_allowed_features.clone(), ) }, @@ -185,7 +198,7 @@ impl<'a, 'hir> LoweringContext<'a, 'hir> { segment, param_mode, generic_args_mode, - itctx, + itctx(i), None, )); let qpath = hir::QPath::TypeRelative(ty, hir_segment); diff --git a/compiler/rustc_ast_passes/messages.ftl b/compiler/rustc_ast_passes/messages.ftl index 92acaaa5f36b0..d81fd53938b89 100644 --- a/compiler/rustc_ast_passes/messages.ftl +++ b/compiler/rustc_ast_passes/messages.ftl @@ -146,8 +146,6 @@ ast_passes_generic_before_constraints = generic arguments must come before the f ast_passes_generic_default_trailing = generic parameters with a default must be trailing -ast_passes_impl_trait_path = `impl Trait` is not allowed in path parameters - ast_passes_incompatible_features = `{$f1}` and `{$f2}` are incompatible, using them at the same time is not allowed .help = remove one of these features diff --git a/compiler/rustc_ast_passes/src/ast_validation.rs b/compiler/rustc_ast_passes/src/ast_validation.rs index bf6ebfb160bc4..485d84b0b6dd3 100644 --- a/compiler/rustc_ast_passes/src/ast_validation.rs +++ b/compiler/rustc_ast_passes/src/ast_validation.rs @@ -80,10 +80,6 @@ struct AstValidator<'a> { disallow_tilde_const: Option, - /// Used to ban `impl Trait` in path projections like `::Item` - /// or `Foo::Bar` - is_impl_trait_banned: bool, - /// Used to ban explicit safety on foreign items when the extern block is not marked as unsafe. extern_mod_safety: Option, @@ -123,12 +119,6 @@ impl<'a> AstValidator<'a> { self.extern_mod_safety = old; } - fn with_banned_impl_trait(&mut self, f: impl FnOnce(&mut Self)) { - let old = mem::replace(&mut self.is_impl_trait_banned, true); - f(self); - self.is_impl_trait_banned = old; - } - fn with_tilde_const( &mut self, disallowed: Option, @@ -213,37 +203,6 @@ impl<'a> AstValidator<'a> { .with_tilde_const(Some(TildeConstReason::TraitObject), |this| { visit::walk_ty(this, t) }), - TyKind::Path(qself, path) => { - // We allow these: - // - `Option` - // - `option::Option` - // - `option::Option::Foo` - // - // But not these: - // - `::Foo` - // - `option::Option::Foo`. - // - // To implement this, we disallow `impl Trait` from `qself` - // (for cases like `::Foo>`) - // but we allow `impl Trait` in `GenericArgs` - // iff there are no more PathSegments. - if let Some(qself) = qself { - // `impl Trait` in `qself` is always illegal - self.with_banned_impl_trait(|this| this.visit_ty(&qself.ty)); - } - - // Note that there should be a call to visit_path here, - // so if any logic is added to process `Path`s a call to it should be - // added both in visit_path and here. This code mirrors visit::walk_path. - for (i, segment) in path.segments.iter().enumerate() { - // Allow `impl Trait` iff we're on the final path segment - if i == path.segments.len() - 1 { - self.visit_path_segment(segment); - } else { - self.with_banned_impl_trait(|this| this.visit_path_segment(segment)); - } - } - } _ => visit::walk_ty(self, t), } } @@ -737,10 +696,6 @@ impl<'a> AstValidator<'a> { } } TyKind::ImplTrait(_, bounds) => { - if self.is_impl_trait_banned { - self.dcx().emit_err(errors::ImplTraitPath { span: ty.span }); - } - if let Some(outer_impl_trait_sp) = self.outer_impl_trait { self.dcx().emit_err(errors::NestedImplTrait { span: ty.span, @@ -1729,7 +1684,6 @@ pub fn check_crate( has_proc_macro_decls: false, outer_impl_trait: None, disallow_tilde_const: Some(TildeConstReason::Item), - is_impl_trait_banned: false, extern_mod_safety: None, lint_buffer: lints, }; diff --git a/compiler/rustc_ast_passes/src/errors.rs b/compiler/rustc_ast_passes/src/errors.rs index 4ca1acde1e289..8c3ac9864ed8a 100644 --- a/compiler/rustc_ast_passes/src/errors.rs +++ b/compiler/rustc_ast_passes/src/errors.rs @@ -418,13 +418,6 @@ pub(crate) struct TraitObjectBound { pub span: Span, } -#[derive(Diagnostic)] -#[diag(ast_passes_impl_trait_path, code = E0667)] -pub(crate) struct ImplTraitPath { - #[primary_span] - pub span: Span, -} - #[derive(Diagnostic)] #[diag(ast_passes_nested_impl_trait, code = E0666)] pub(crate) struct NestedImplTrait { diff --git a/compiler/rustc_error_codes/src/error_codes/E0667.md b/compiler/rustc_error_codes/src/error_codes/E0667.md index 0709a24c43312..339bc0686103a 100644 --- a/compiler/rustc_error_codes/src/error_codes/E0667.md +++ b/compiler/rustc_error_codes/src/error_codes/E0667.md @@ -1,8 +1,10 @@ +#### Note: this error code is no longer emitted by the compiler. + `impl Trait` is not allowed in path parameters. Erroneous code example: -```compile_fail,E0667 +```ignore (removed error code) fn some_fn(mut x: impl Iterator) -> ::Item { // error! x.next().unwrap() } @@ -11,7 +13,7 @@ fn some_fn(mut x: impl Iterator) -> ::Item { // error! You cannot use `impl Trait` in path parameters. If you want something equivalent, you can do this instead: -``` +```ignore (removed error code) fn some_fn(mut x: T) -> T::Item { // ok! x.next().unwrap() } diff --git a/compiler/rustc_hir_analysis/src/hir_ty_lowering/mod.rs b/compiler/rustc_hir_analysis/src/hir_ty_lowering/mod.rs index 863c077a9e03c..cfd1241ad69c8 100644 --- a/compiler/rustc_hir_analysis/src/hir_ty_lowering/mod.rs +++ b/compiler/rustc_hir_analysis/src/hir_ty_lowering/mod.rs @@ -1203,15 +1203,6 @@ impl<'tcx> dyn HirTyLowerer<'tcx> + '_ { err.emit() } else if let Err(reported) = qself_ty.error_reported() { reported - } else if let ty::Alias(ty::Opaque, alias_ty) = qself_ty.kind() { - // `::Assoc` makes no sense. - struct_span_code_err!( - self.dcx(), - tcx.def_span(alias_ty.def_id), - E0667, - "`impl Trait` is not allowed in path parameters" - ) - .emit() // Already reported in an earlier stage. } else { self.maybe_report_similar_assoc_fn(span, qself_ty, qself)?; diff --git a/tests/crashes/126725.rs b/tests/crashes/126725.rs deleted file mode 100644 index d7a7d21ae4244..0000000000000 --- a/tests/crashes/126725.rs +++ /dev/null @@ -1,20 +0,0 @@ -//@ known-bug: rust-lang/rust#126725 -trait Foo { - fn foo<'a>(&'a self) -> <&'a impl Sized as Bar>::Output; -} - -trait Bar { - type Output; -} - -struct X(i32); - -impl<'a> Bar for &'a X { - type Output = &'a i32; -} - -impl Foo for X { - fn foo<'a>(&'a self) -> <&'a Self as Bar>::Output { - &self.0 - } -} diff --git a/tests/ui/impl-trait/impl_trait_projections.rs b/tests/ui/impl-trait/impl_trait_projections.rs index 365ac85e2f665..2c277aee06dad 100644 --- a/tests/ui/impl-trait/impl_trait_projections.rs +++ b/tests/ui/impl-trait/impl_trait_projections.rs @@ -10,30 +10,27 @@ fn path_parametrized_type_is_allowed() -> option::Option { } fn projection_is_disallowed(x: impl Iterator) -> ::Item { -//~^ ERROR `impl Trait` is not allowed in path parameters -//~| ERROR `impl Trait` is not allowed in path parameters +//~^ ERROR `impl Trait` is not allowed in paths x.next().unwrap() } fn projection_with_named_trait_is_disallowed(mut x: impl Iterator) -> ::Item -//~^ ERROR `impl Trait` is not allowed in path parameters +//~^ ERROR `impl Trait` is not allowed in paths { x.next().unwrap() } fn projection_with_named_trait_inside_path_is_disallowed() -> <::std::ops::Range as Iterator>::Item -//~^ ERROR `impl Trait` is not allowed in path parameters -//~| ERROR `impl Debug: Step` is not satisfied +//~^ ERROR `impl Trait` is not allowed in paths { - //~^ ERROR `impl Debug: Step` is not satisfied (1i32..100).next().unwrap() } fn projection_from_impl_trait_inside_dyn_trait_is_disallowed() -> as Iterator>::Item -//~^ ERROR `impl Trait` is not allowed in path parameters +//~^ ERROR `impl Trait` is not allowed in paths { panic!() } diff --git a/tests/ui/impl-trait/impl_trait_projections.stderr b/tests/ui/impl-trait/impl_trait_projections.stderr index d62e3ac4183f5..5e0b80fcd5922 100644 --- a/tests/ui/impl-trait/impl_trait_projections.stderr +++ b/tests/ui/impl-trait/impl_trait_projections.stderr @@ -1,73 +1,35 @@ -error[E0667]: `impl Trait` is not allowed in path parameters +error[E0562]: `impl Trait` is not allowed in paths --> $DIR/impl_trait_projections.rs:12:51 | LL | fn projection_is_disallowed(x: impl Iterator) -> ::Item { | ^^^^^^^^^^^^^ + | + = note: `impl Trait` is only allowed in arguments and return types of functions and methods -error[E0667]: `impl Trait` is not allowed in path parameters - --> $DIR/impl_trait_projections.rs:19:9 +error[E0562]: `impl Trait` is not allowed in paths + --> $DIR/impl_trait_projections.rs:18:9 | LL | -> ::Item | ^^^^^^^^^^^^^ + | + = note: `impl Trait` is only allowed in arguments and return types of functions and methods -error[E0667]: `impl Trait` is not allowed in path parameters - --> $DIR/impl_trait_projections.rs:26:27 +error[E0562]: `impl Trait` is not allowed in paths + --> $DIR/impl_trait_projections.rs:25:27 | LL | -> <::std::ops::Range as Iterator>::Item | ^^^^^^^^^^ + | + = note: `impl Trait` is only allowed in arguments and return types of functions and methods -error[E0667]: `impl Trait` is not allowed in path parameters - --> $DIR/impl_trait_projections.rs:35:29 +error[E0562]: `impl Trait` is not allowed in paths + --> $DIR/impl_trait_projections.rs:32:29 | LL | -> as Iterator>::Item | ^^^^^^^^^^ - -error[E0667]: `impl Trait` is not allowed in path parameters - --> $DIR/impl_trait_projections.rs:12:51 - | -LL | fn projection_is_disallowed(x: impl Iterator) -> ::Item { - | ^^^^^^^^^^^^^ - -error[E0277]: the trait bound `impl Debug: Step` is not satisfied - --> $DIR/impl_trait_projections.rs:26:8 - | -LL | -> <::std::ops::Range as Iterator>::Item - | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ the trait `Step` is not implemented for `impl Debug`, which is required by `std::ops::Range: Iterator` - | - = help: the following other types implement trait `Step`: - Char - Ipv4Addr - Ipv6Addr - char - i128 - i16 - i32 - i64 - and 8 others - = note: required for `std::ops::Range` to implement `Iterator` - -error[E0277]: the trait bound `impl Debug: Step` is not satisfied - --> $DIR/impl_trait_projections.rs:29:1 - | -LL | / { -LL | | -LL | | (1i32..100).next().unwrap() -LL | | } - | |_^ the trait `Step` is not implemented for `impl Debug`, which is required by `std::ops::Range: Iterator` | - = help: the following other types implement trait `Step`: - Char - Ipv4Addr - Ipv6Addr - char - i128 - i16 - i32 - i64 - and 8 others - = note: required for `std::ops::Range` to implement `Iterator` + = note: `impl Trait` is only allowed in arguments and return types of functions and methods -error: aborting due to 7 previous errors +error: aborting due to 4 previous errors -Some errors have detailed explanations: E0277, E0667. -For more information about an error, try `rustc --explain E0277`. +For more information about this error, try `rustc --explain E0562`. diff --git a/tests/ui/impl-trait/in-trait/bad-projection-from-opaque.rs b/tests/ui/impl-trait/in-trait/bad-projection-from-opaque.rs new file mode 100644 index 0000000000000..c2c22cd1abfcc --- /dev/null +++ b/tests/ui/impl-trait/in-trait/bad-projection-from-opaque.rs @@ -0,0 +1,22 @@ +// issue: rust-lang/rust#126725 + +trait Foo { + fn foo<'a>() -> <&'a impl Sized as Bar>::Output; + //~^ ERROR `impl Trait` is not allowed in paths +} + +trait Bar { + type Output; +} + +impl<'a> Bar for &'a () { + type Output = &'a i32; +} + +impl Foo for () { + fn foo<'a>() -> <&'a Self as Bar>::Output { + &0 + } +} + +fn main() {} diff --git a/tests/ui/impl-trait/in-trait/bad-projection-from-opaque.stderr b/tests/ui/impl-trait/in-trait/bad-projection-from-opaque.stderr new file mode 100644 index 0000000000000..bea7ccd1a18d0 --- /dev/null +++ b/tests/ui/impl-trait/in-trait/bad-projection-from-opaque.stderr @@ -0,0 +1,11 @@ +error[E0562]: `impl Trait` is not allowed in paths + --> $DIR/bad-projection-from-opaque.rs:4:26 + | +LL | fn foo<'a>() -> <&'a impl Sized as Bar>::Output; + | ^^^^^^^^^^ + | + = note: `impl Trait` is only allowed in arguments and return types of functions and methods + +error: aborting due to 1 previous error + +For more information about this error, try `rustc --explain E0562`. diff --git a/tests/ui/impl-trait/issues/issue-57979-impl-trait-in-path.rs b/tests/ui/impl-trait/issues/issue-57979-impl-trait-in-path.rs index c5ecd1caae1f9..9466668b1dcd4 100644 --- a/tests/ui/impl-trait/issues/issue-57979-impl-trait-in-path.rs +++ b/tests/ui/impl-trait/issues/issue-57979-impl-trait-in-path.rs @@ -6,7 +6,7 @@ pub trait Bar { } pub trait Quux { type Assoc; } pub fn demo(_: impl Quux<(), Assoc=<() as Quux>::Assoc>) { } -//~^ ERROR `impl Trait` is not allowed in path parameters +//~^ ERROR `impl Trait` is not allowed in paths impl Quux for () { type Assoc = u32; } fn main() { } diff --git a/tests/ui/impl-trait/issues/issue-57979-impl-trait-in-path.stderr b/tests/ui/impl-trait/issues/issue-57979-impl-trait-in-path.stderr index 55f47785f0eeb..25547dfa66f5d 100644 --- a/tests/ui/impl-trait/issues/issue-57979-impl-trait-in-path.stderr +++ b/tests/ui/impl-trait/issues/issue-57979-impl-trait-in-path.stderr @@ -1,9 +1,11 @@ -error[E0667]: `impl Trait` is not allowed in path parameters +error[E0562]: `impl Trait` is not allowed in paths --> $DIR/issue-57979-impl-trait-in-path.rs:8:48 | LL | pub fn demo(_: impl Quux<(), Assoc=<() as Quux>::Assoc>) { } | ^^^^^^^^ + | + = note: `impl Trait` is only allowed in arguments and return types of functions and methods error: aborting due to 1 previous error -For more information about this error, try `rustc --explain E0667`. +For more information about this error, try `rustc --explain E0562`.