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Warn on elided lifetimes in associated constants

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This commit is contained in:
Michael Goulet 2023-08-19 23:27:50 +00:00
parent 6ef7d16be0
commit fad7d220fd
8 changed files with 178 additions and 25 deletions
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79
compiler/rustc_resolve/src/late.rs
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@ -311,6 +311,10 @@ enum LifetimeRibKind {
/// error on default object bounds (e.g., `Box<dyn Foo>`).
AnonymousReportError,
/// Resolves elided lifetimes to `'static`, but gives a warning that this behavior
/// is a bug and will be reverted soon.
AnonymousWarnToStatic(NodeId),
/// Signal we cannot find which should be the anonymous lifetime.
ElisionFailure,
@ -1148,6 +1152,7 @@ impl<'a: 'ast, 'ast, 'tcx> Visitor<'ast> for LateResolutionVisitor<'a, '_, 'ast,
}
LifetimeRibKind::AnonymousCreateParameter { .. }
| LifetimeRibKind::AnonymousReportError
| LifetimeRibKind::AnonymousWarnToStatic(_)
| LifetimeRibKind::Elided(_)
| LifetimeRibKind::ElisionFailure
| LifetimeRibKind::ConcreteAnonConst(_)
@ -1515,6 +1520,7 @@ impl<'a: 'ast, 'b, 'ast, 'tcx> LateResolutionVisitor<'a, 'b, 'ast, 'tcx> {
// lifetime would be illegal.
LifetimeRibKind::Item
| LifetimeRibKind::AnonymousReportError
| LifetimeRibKind::AnonymousWarnToStatic(_)
| LifetimeRibKind::ElisionFailure => Some(LifetimeUseSet::Many),
// An anonymous lifetime is legal here, and bound to the right
// place, go ahead.
@ -1576,7 +1582,8 @@ impl<'a: 'ast, 'b, 'ast, 'tcx> LateResolutionVisitor<'a, 'b, 'ast, 'tcx> {
| LifetimeRibKind::Elided(_)
| LifetimeRibKind::Generics { .. }
| LifetimeRibKind::ElisionFailure
| LifetimeRibKind::AnonymousReportError => {}
| LifetimeRibKind::AnonymousReportError
| LifetimeRibKind::AnonymousWarnToStatic(_) => {}
}
}
@ -1616,6 +1623,25 @@ impl<'a: 'ast, 'b, 'ast, 'tcx> LateResolutionVisitor<'a, 'b, 'ast, 'tcx> {
self.record_lifetime_res(lifetime.id, res, elision_candidate);
return;
}
LifetimeRibKind::AnonymousWarnToStatic(node_id) => {
self.record_lifetime_res(lifetime.id, LifetimeRes::Static, elision_candidate);
let msg = if elided {
"`&` without an explicit lifetime name cannot be used here"
} else {
"`'_` cannot be used here"
};
self.r.lint_buffer.buffer_lint_with_diagnostic(
lint::builtin::ELIDED_LIFETIMES_IN_ASSOCIATED_CONSTANT,
node_id,
lifetime.ident.span,
msg,
lint::BuiltinLintDiagnostics::AssociatedConstElidedLifetime {
elided,
span: lifetime.ident.span,
},
);
return;
}
LifetimeRibKind::AnonymousReportError => {
let (msg, note) = if elided {
(
@ -1811,7 +1837,8 @@ impl<'a: 'ast, 'b, 'ast, 'tcx> LateResolutionVisitor<'a, 'b, 'ast, 'tcx> {
//
// impl Foo for std::cell::Ref<u32> // note lack of '_
// async fn foo(_: std::cell::Ref<u32>) { ... }
LifetimeRibKind::AnonymousCreateParameter { report_in_path: true, .. } => {
LifetimeRibKind::AnonymousCreateParameter { report_in_path: true, .. }
| LifetimeRibKind::AnonymousWarnToStatic(_) => {
let sess = self.r.tcx.sess;
let mut err = rustc_errors::struct_span_err!(
sess,
@ -2898,7 +2925,6 @@ impl<'a: 'ast, 'b, 'ast, 'tcx> LateResolutionVisitor<'a, 'b, 'ast, 'tcx> {
match &item.kind {
AssocItemKind::Const(box ast::ConstItem { generics, ty, expr, .. }) => {
debug!("resolve_implementation AssocItemKind::Const");
self.with_generic_param_rib(
&generics.params,
RibKind::AssocItem,
@ -2908,28 +2934,33 @@ impl<'a: 'ast, 'b, 'ast, 'tcx> LateResolutionVisitor<'a, 'b, 'ast, 'tcx> {
kind: LifetimeBinderKind::ConstItem,
},
|this| {
// If this is a trait impl, ensure the const
// exists in trait
this.check_trait_item(
item.id,
item.ident,
&item.kind,
ValueNS,
item.span,
seen_trait_items,
|i, s, c| ConstNotMemberOfTrait(i, s, c),
);
this.with_lifetime_rib(
LifetimeRibKind::AnonymousWarnToStatic(item.id),
|this| {
// If this is a trait impl, ensure the const
// exists in trait
this.check_trait_item(
item.id,
item.ident,
&item.kind,
ValueNS,
item.span,
seen_trait_items,
|i, s, c| ConstNotMemberOfTrait(i, s, c),
);
this.visit_generics(generics);
this.visit_ty(ty);
if let Some(expr) = expr {
// We allow arbitrary const expressions inside of associated consts,
// even if they are potentially not const evaluatable.
//
// Type parameters can already be used and as associated consts are
// not used as part of the type system, this is far less surprising.
this.resolve_const_body(expr, None);
}
this.visit_generics(generics);
this.visit_ty(ty);
if let Some(expr) = expr {
// We allow arbitrary const expressions inside of associated consts,
// even if they are potentially not const evaluatable.
//
// Type parameters can already be used and as associated consts are
// not used as part of the type system, this is far less surprising.
this.resolve_const_body(expr, None);
}
},
);
},
);
}