bjoernager/rust
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Allow ~const on assoc ty bounds again

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This commit is contained in:
León Orell Valerian Liehr 2024-01-12 16:37:25 +01:00
parent e927184629
commit f28373978e
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GPG key ID: D17A07215F68E713
13 changed files with 202 additions and 64 deletions
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38
compiler/rustc_ast_passes/src/ast_validation.rs
View file

@ -37,12 +37,17 @@ enum SelfSemantic {
}
/// What is the context that prevents using `~const`?
// FIXME(effects): Consider getting rid of this in favor of `errors::TildeConstReason`, they're
// almost identical. This gets rid of an abstraction layer which might be considered bad.
enum DisallowTildeConstContext<'a> {
TraitObject,
Fn(FnKind<'a>),
Trait(Span),
TraitImpl(Span),
Impl(Span),
TraitAssocTy(Span),
TraitImplAssocTy(Span),
InherentAssocTy(Span),
Item,
}
@ -316,6 +321,7 @@ impl<'a> AstValidator<'a> {
constness: Const::No,
polarity: ImplPolarity::Positive,
trait_ref,
..
} = parent
{
Some(trait_ref.path.span.shrink_to_lo())
@ -1286,6 +1292,15 @@ impl<'a> Visitor<'a> for AstValidator<'a> {
// suggestion for moving such bounds to the assoc const fns if available.
errors::TildeConstReason::Impl { span }
}
&DisallowTildeConstContext::TraitAssocTy(span) => {
errors::TildeConstReason::TraitAssocTy { span }
}
&DisallowTildeConstContext::TraitImplAssocTy(span) => {
errors::TildeConstReason::TraitImplAssocTy { span }
}
&DisallowTildeConstContext::InherentAssocTy(span) => {
errors::TildeConstReason::InherentAssocTy { span }
}
DisallowTildeConstContext::TraitObject => {
errors::TildeConstReason::TraitObject
}
@ -1483,13 +1498,12 @@ impl<'a> Visitor<'a> for AstValidator<'a> {
self.check_item_named(item.ident, "const");
}
let parent_is_const =
self.outer_trait_or_trait_impl.as_ref().and_then(TraitOrTraitImpl::constness).is_some();
match &item.kind {
AssocItemKind::Fn(box Fn { sig, generics, body, .. })
if self
.outer_trait_or_trait_impl
.as_ref()
.and_then(TraitOrTraitImpl::constness)
.is_some()
if parent_is_const
|| ctxt == AssocCtxt::Trait
|| matches!(sig.header.constness, Const::Yes(_)) =>
{
@ -1505,6 +1519,20 @@ impl<'a> Visitor<'a> for AstValidator<'a> {
);
self.visit_fn(kind, item.span, item.id);
}
AssocItemKind::Type(_) => {
let disallowed = (!parent_is_const).then(|| match self.outer_trait_or_trait_impl {
Some(TraitOrTraitImpl::Trait { .. }) => {
DisallowTildeConstContext::TraitAssocTy(item.span)
}
Some(TraitOrTraitImpl::TraitImpl { .. }) => {
DisallowTildeConstContext::TraitImplAssocTy(item.span)
}
None => DisallowTildeConstContext::InherentAssocTy(item.span),
});
self.with_tilde_const(disallowed, |this| {
this.with_in_trait_impl(None, |this| visit::walk_assoc_item(this, item, ctxt))
})
}
_ => self.with_in_trait_impl(None, |this| visit::walk_assoc_item(this, item, ctxt)),
}
}

17
compiler/rustc_ast_passes/src/errors.rs
View file

@ -565,6 +565,8 @@ pub struct ConstBoundTraitObject {
pub span: Span,
}
// FIXME(effects): Consider making the note/reason the message of the diagnostic.
// FIXME(effects): Provide structured suggestions (e.g., add `const` / `#[const_trait]` here).
#[derive(Diagnostic)]
#[diag(ast_passes_tilde_const_disallowed)]
pub struct TildeConstDisallowed {
@ -598,6 +600,21 @@ pub enum TildeConstReason {
#[primary_span]
span: Span,
},
#[note(ast_passes_trait_assoc_ty)]
TraitAssocTy {
#[primary_span]
span: Span,
},
#[note(ast_passes_trait_impl_assoc_ty)]
TraitImplAssocTy {
#[primary_span]
span: Span,
},
#[note(ast_passes_inherent_assoc_ty)]
InherentAssocTy {
#[primary_span]
span: Span,
},
#[note(ast_passes_object)]
TraitObject,
#[note(ast_passes_item)]