From 7d78968bd053eb7811126b2bad991579fb78cc3a Mon Sep 17 00:00:00 2001 From: Shoyu Vanilla Date: Fri, 1 Aug 2025 00:23:36 +0900 Subject: [PATCH] fix: Error on illegal `[const]`s inside blocks within legal positions --- compiler/rustc_ast_passes/messages.ftl | 4 ++ .../rustc_ast_passes/src/ast_validation.rs | 47 ++++++++++++------- compiler/rustc_ast_passes/src/errors.rs | 20 ++++++++ .../conditionally-const-in-anon-const.rs | 28 +++++++++++ .../conditionally-const-in-anon-const.stderr | 32 +++++++++++++ .../conditionally-const-in-struct-args.rs | 21 --------- .../conditionally-const-invalid-places.stderr | 30 ++++++++++-- 7 files changed, 140 insertions(+), 42 deletions(-) create mode 100644 tests/ui/traits/const-traits/conditionally-const-in-anon-const.rs create mode 100644 tests/ui/traits/const-traits/conditionally-const-in-anon-const.stderr delete mode 100644 tests/ui/traits/const-traits/conditionally-const-in-struct-args.rs diff --git a/compiler/rustc_ast_passes/messages.ftl b/compiler/rustc_ast_passes/messages.ftl index af93d55c89826..42f3569f0f1e1 100644 --- a/compiler/rustc_ast_passes/messages.ftl +++ b/compiler/rustc_ast_passes/messages.ftl @@ -241,6 +241,10 @@ ast_passes_tilde_const_disallowed = `[const]` is not allowed here .trait_assoc_ty = associated types in non-`const` traits cannot have `[const]` trait bounds .trait_impl_assoc_ty = associated types in non-const impls cannot have `[const]` trait bounds .inherent_assoc_ty = inherent associated types cannot have `[const]` trait bounds + .struct = structs cannot have `[const]` trait bounds + .enum = enums cannot have `[const]` trait bounds + .union = unions cannot have `[const]` trait bounds + .anon_const = anonymous constants cannot have `[const]` trait bounds .object = trait objects cannot have `[const]` trait bounds .item = this item cannot have `[const]` trait bounds diff --git a/compiler/rustc_ast_passes/src/ast_validation.rs b/compiler/rustc_ast_passes/src/ast_validation.rs index 895a457ec1d56..ae482ceb9b72b 100644 --- a/compiler/rustc_ast_passes/src/ast_validation.rs +++ b/compiler/rustc_ast_passes/src/ast_validation.rs @@ -1124,7 +1124,9 @@ impl<'a> Visitor<'a> for AstValidator<'a> { ); } } - visit::walk_item(self, item) + self.with_tilde_const(Some(TildeConstReason::Enum { span: item.span }), |this| { + visit::walk_item(this, item) + }); } ItemKind::Trait(box Trait { constness, @@ -1175,26 +1177,32 @@ impl<'a> Visitor<'a> for AstValidator<'a> { } visit::walk_item(self, item) } - ItemKind::Struct(ident, generics, vdata) => match vdata { - VariantData::Struct { fields, .. } => { - self.visit_attrs_vis_ident(&item.attrs, &item.vis, ident); - self.visit_generics(generics); - walk_list!(self, visit_field_def, fields); - } - _ => visit::walk_item(self, item), - }, + ItemKind::Struct(ident, generics, vdata) => { + self.with_tilde_const(Some(TildeConstReason::Struct { span: item.span }), |this| { + match vdata { + VariantData::Struct { fields, .. } => { + this.visit_attrs_vis_ident(&item.attrs, &item.vis, ident); + this.visit_generics(generics); + walk_list!(this, visit_field_def, fields); + } + _ => visit::walk_item(this, item), + } + }) + } ItemKind::Union(ident, generics, vdata) => { if vdata.fields().is_empty() { self.dcx().emit_err(errors::FieldlessUnion { span: item.span }); } - match vdata { - VariantData::Struct { fields, .. } => { - self.visit_attrs_vis_ident(&item.attrs, &item.vis, ident); - self.visit_generics(generics); - walk_list!(self, visit_field_def, fields); + self.with_tilde_const(Some(TildeConstReason::Union { span: item.span }), |this| { + match vdata { + VariantData::Struct { fields, .. } => { + this.visit_attrs_vis_ident(&item.attrs, &item.vis, ident); + this.visit_generics(generics); + walk_list!(this, visit_field_def, fields); + } + _ => visit::walk_item(this, item), } - _ => visit::walk_item(self, item), - } + }); } ItemKind::Const(box ConstItem { defaultness, expr, .. }) => { self.check_defaultness(item.span, *defaultness); @@ -1623,6 +1631,13 @@ impl<'a> Visitor<'a> for AstValidator<'a> { _ => self.with_in_trait_impl(None, |this| visit::walk_assoc_item(this, item, ctxt)), } } + + fn visit_anon_const(&mut self, anon_const: &'a AnonConst) { + self.with_tilde_const( + Some(TildeConstReason::AnonConst { span: anon_const.value.span }), + |this| visit::walk_anon_const(this, anon_const), + ) + } } /// When encountering an equality constraint in a `where` clause, emit an error. If the code seems diff --git a/compiler/rustc_ast_passes/src/errors.rs b/compiler/rustc_ast_passes/src/errors.rs index fd4b2528541e3..8b5873a3ef37a 100644 --- a/compiler/rustc_ast_passes/src/errors.rs +++ b/compiler/rustc_ast_passes/src/errors.rs @@ -623,6 +623,26 @@ pub(crate) enum TildeConstReason { #[primary_span] span: Span, }, + #[note(ast_passes_struct)] + Struct { + #[primary_span] + span: Span, + }, + #[note(ast_passes_enum)] + Enum { + #[primary_span] + span: Span, + }, + #[note(ast_passes_union)] + Union { + #[primary_span] + span: Span, + }, + #[note(ast_passes_anon_const)] + AnonConst { + #[primary_span] + span: Span, + }, #[note(ast_passes_object)] TraitObject, #[note(ast_passes_item)] diff --git a/tests/ui/traits/const-traits/conditionally-const-in-anon-const.rs b/tests/ui/traits/const-traits/conditionally-const-in-anon-const.rs new file mode 100644 index 0000000000000..5aebcceb7c75d --- /dev/null +++ b/tests/ui/traits/const-traits/conditionally-const-in-anon-const.rs @@ -0,0 +1,28 @@ +#![feature(const_trait_impl, impl_trait_in_bindings)] + +struct S; +#[const_trait] +trait Trait {} + +impl const Trait<0> for () {} + +const fn f< + T: Trait< + { + const fn g>() {} + + struct I>(U); + //~^ ERROR `[const]` is not allowed here + + let x: &impl [const] Trait<0> = &(); + //~^ ERROR `[const]` is not allowed here + + 0 + }, + >, +>(x: &T) { + // Should be allowed here + let y: &impl [const] Trait<0> = x; +} + +pub fn main() {} diff --git a/tests/ui/traits/const-traits/conditionally-const-in-anon-const.stderr b/tests/ui/traits/const-traits/conditionally-const-in-anon-const.stderr new file mode 100644 index 0000000000000..c6be249b95a22 --- /dev/null +++ b/tests/ui/traits/const-traits/conditionally-const-in-anon-const.stderr @@ -0,0 +1,32 @@ +error: `[const]` is not allowed here + --> $DIR/conditionally-const-in-anon-const.rs:14:25 + | +LL | struct I>(U); + | ^^^^^^^ + | +note: structs cannot have `[const]` trait bounds + --> $DIR/conditionally-const-in-anon-const.rs:14:13 + | +LL | struct I>(U); + | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ + +error: `[const]` is not allowed here + --> $DIR/conditionally-const-in-anon-const.rs:17:26 + | +LL | let x: &impl [const] Trait<0> = &(); + | ^^^^^^^ + | +note: anonymous constants cannot have `[const]` trait bounds + --> $DIR/conditionally-const-in-anon-const.rs:11:9 + | +LL | / { +LL | | const fn g>() {} +LL | | +LL | | struct I>(U); +... | +LL | | 0 +LL | | }, + | |_________^ + +error: aborting due to 2 previous errors + diff --git a/tests/ui/traits/const-traits/conditionally-const-in-struct-args.rs b/tests/ui/traits/const-traits/conditionally-const-in-struct-args.rs deleted file mode 100644 index 0c644694585a6..0000000000000 --- a/tests/ui/traits/const-traits/conditionally-const-in-struct-args.rs +++ /dev/null @@ -1,21 +0,0 @@ -//@ compile-flags: -Znext-solver -//@ known-bug: #132067 -//@ check-pass - -#![feature(const_trait_impl)] - -struct S; -#[const_trait] -trait Trait {} - -const fn f< - T: Trait< - { - struct I>(U); - 0 - }, - >, ->() { -} - -pub fn main() {} diff --git a/tests/ui/traits/const-traits/conditionally-const-invalid-places.stderr b/tests/ui/traits/const-traits/conditionally-const-invalid-places.stderr index 010b158464361..5c3bb2369675e 100644 --- a/tests/ui/traits/const-traits/conditionally-const-invalid-places.stderr +++ b/tests/ui/traits/const-traits/conditionally-const-invalid-places.stderr @@ -16,7 +16,11 @@ error: `[const]` is not allowed here LL | struct Struct { field: T } | ^^^^^^^ | - = note: this item cannot have `[const]` trait bounds +note: structs cannot have `[const]` trait bounds + --> $DIR/conditionally-const-invalid-places.rs:9:1 + | +LL | struct Struct { field: T } + | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ error: `[const]` is not allowed here --> $DIR/conditionally-const-invalid-places.rs:10:23 @@ -24,7 +28,11 @@ error: `[const]` is not allowed here LL | struct TupleStruct(T); | ^^^^^^^ | - = note: this item cannot have `[const]` trait bounds +note: structs cannot have `[const]` trait bounds + --> $DIR/conditionally-const-invalid-places.rs:10:1 + | +LL | struct TupleStruct(T); + | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ error: `[const]` is not allowed here --> $DIR/conditionally-const-invalid-places.rs:11:22 @@ -32,7 +40,11 @@ error: `[const]` is not allowed here LL | struct UnitStruct; | ^^^^^^^ | - = note: this item cannot have `[const]` trait bounds +note: structs cannot have `[const]` trait bounds + --> $DIR/conditionally-const-invalid-places.rs:11:1 + | +LL | struct UnitStruct; + | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ error: `[const]` is not allowed here --> $DIR/conditionally-const-invalid-places.rs:14:14 @@ -40,7 +52,11 @@ error: `[const]` is not allowed here LL | enum Enum { Variant(T) } | ^^^^^^^ | - = note: this item cannot have `[const]` trait bounds +note: enums cannot have `[const]` trait bounds + --> $DIR/conditionally-const-invalid-places.rs:14:1 + | +LL | enum Enum { Variant(T) } + | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ error: `[const]` is not allowed here --> $DIR/conditionally-const-invalid-places.rs:16:16 @@ -48,7 +64,11 @@ error: `[const]` is not allowed here LL | union Union { field: T } | ^^^^^^^ | - = note: this item cannot have `[const]` trait bounds +note: unions cannot have `[const]` trait bounds + --> $DIR/conditionally-const-invalid-places.rs:16:1 + | +LL | union Union { field: T } + | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ error: `[const]` is not allowed here --> $DIR/conditionally-const-invalid-places.rs:19:14