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Use the correct binder scope for elided lifetimes in assoc consts #138985

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Merged
merged 1 commit into from
Mar 27, 2025
Merged

Use the correct binder scope for elided lifetimes in assoc consts #138985

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60 changes: 35 additions & 25 deletions compiler/rustc_resolve/src/late.rs
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Original file line number Diff line number Diff line change
Expand Up @@ -3334,34 +3334,44 @@ impl<'a, 'ast, 'ra: 'ast, 'tcx> LateResolutionVisitor<'a, 'ast, 'ra, 'tcx> {
},
|this| {
this.with_lifetime_rib(
LifetimeRibKind::StaticIfNoLifetimeInScope {
lint_id: item.id,
// In impls, it's not a hard error yet due to backcompat.
emit_lint: true,
// Until these are a hard error, we need to create them within the correct binder,
// Otherwise the lifetimes of this assoc const think they are lifetimes of the trait.
LifetimeRibKind::AnonymousCreateParameter {
binder: item.id,
report_in_path: true,
},
|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::StaticIfNoLifetimeInScope {
lint_id: item.id,
// In impls, it's not a hard error yet due to backcompat.
emit_lint: true,
},
|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);
}
},
)
},
);
},
Expand Down
2 changes: 0 additions & 2 deletions tests/ui/consts/assoc-const-elided-lifetime.stderr
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Expand Up @@ -35,8 +35,6 @@ note: cannot automatically infer `'static` because of other lifetimes in scope
|
LL | impl<'a> Foo<'a> {
| ^^
LL | const FOO: Foo<'_> = Foo { x: PhantomData::<&()> };
| ^^
help: use the `'static` lifetime
|
LL | const BAR: &'static () = &();
Expand Down
2 changes: 1 addition & 1 deletion tests/ui/consts/static-default-lifetime/elided-lifetime.rs
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Expand Up @@ -16,7 +16,7 @@ impl Bar for Foo<'_> {
const STATIC: &str = "";
//~^ ERROR `&` without an explicit lifetime name cannot be used here
//~| WARN this was previously accepted by the compiler but is being phased out
//~| ERROR const not compatible with trait
//~| ERROR lifetime parameters or bounds on const `STATIC` do not match the trait declaration
}

fn main() {}
20 changes: 7 additions & 13 deletions tests/ui/consts/static-default-lifetime/elided-lifetime.stderr
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Original file line number Diff line number Diff line change
Expand Up @@ -39,21 +39,15 @@ help: use the `'static` lifetime
LL | const STATIC: &'static str = "";
| +++++++

error[E0308]: const not compatible with trait
--> $DIR/elided-lifetime.rs:16:5
error[E0195]: lifetime parameters or bounds on const `STATIC` do not match the trait declaration
--> $DIR/elided-lifetime.rs:16:17
|
LL | const STATIC: &str;
| - lifetimes in impl do not match this const in trait
...
LL | const STATIC: &str = "";
| ^^^^^^^^^^^^^^^^^^ lifetime mismatch
|
= note: expected reference `&'static _`
found reference `&_`
note: the anonymous lifetime as defined here...
--> $DIR/elided-lifetime.rs:16:19
|
LL | const STATIC: &str = "";
| ^
= note: ...does not necessarily outlive the static lifetime
| ^ lifetimes do not match const in trait

error: aborting due to 3 previous errors

For more information about this error, try `rustc --explain E0308`.
For more information about this error, try `rustc --explain E0195`.
2 changes: 1 addition & 1 deletion tests/ui/consts/static-default-lifetime/static-trait-impl.rs
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Expand Up @@ -9,7 +9,7 @@ impl Bar<'_> for A {
const STATIC: &str = "";
//~^ ERROR `&` without an explicit lifetime name cannot be used here
//~| WARN this was previously accepted by the compiler but is being phased out
//~| ERROR const not compatible with trait
//~| ERROR lifetime parameters or bounds on const `STATIC` do not match the trait declaration
}

struct B;
Expand Down
24 changes: 7 additions & 17 deletions tests/ui/consts/static-default-lifetime/static-trait-impl.stderr
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Original file line number Diff line number Diff line change
Expand Up @@ -21,25 +21,15 @@ help: use the `'static` lifetime
LL | const STATIC: &'static str = "";
| +++++++

error[E0308]: const not compatible with trait
--> $DIR/static-trait-impl.rs:9:5
error[E0195]: lifetime parameters or bounds on const `STATIC` do not match the trait declaration
--> $DIR/static-trait-impl.rs:9:17
|
LL | const STATIC: &'a str;
| - lifetimes in impl do not match this const in trait
...
LL | const STATIC: &str = "";
| ^^^^^^^^^^^^^^^^^^ lifetime mismatch
|
= note: expected reference `&_`
found reference `&_`
note: the anonymous lifetime as defined here...
--> $DIR/static-trait-impl.rs:9:19
|
LL | const STATIC: &str = "";
| ^
note: ...does not necessarily outlive the anonymous lifetime as defined here
--> $DIR/static-trait-impl.rs:8:10
|
LL | impl Bar<'_> for A {
| ^^
| ^ lifetimes do not match const in trait

error: aborting due to 2 previous errors

For more information about this error, try `rustc --explain E0308`.
For more information about this error, try `rustc --explain E0195`.
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