user0/rust
1
0
Fork 0
Code Issues Pull requests Projects Releases Packages Wiki Activity Actions

Tweak diagnostics for relaxed bounds in invalid positions

Browse source
This commit is contained in:
León Orell Valerian Liehr 2025-10-16 19:53:29 +02:00
parent 7a52736039
commit 690a8a6dfd
No known key found for this signature in database
GPG key ID: D17A07215F68E713
7 changed files with 49 additions and 35 deletions
Download patch file Download diff file Expand all files Collapse all files

46
compiler/rustc_ast_lowering/src/lib.rs
View file

@ -2103,33 +2103,33 @@ impl<'a, 'hir> LoweringContext<'a, 'hir> {
}
}
RelaxedBoundPolicy::Forbidden(reason) => {
let gate = |context, subject| {
if self.tcx.features().more_maybe_bounds() {
return;
}
let mut diag = self.dcx().struct_span_err(
span,
format!("relaxed bounds are not permitted in {context}"),
);
if let Some(def_id) = trait_ref.trait_def_id()
&& self.tcx.is_lang_item(def_id, hir::LangItem::Sized)
{
diag.note(format!(
"{subject} are not implicitly bounded by `Sized`, \
so there is nothing to relax"
));
}
diag.emit();
};
match reason {
RelaxedBoundForbiddenReason::TraitObjectTy => {
if self.tcx.features().more_maybe_bounds() {
return;
}
self.dcx().span_err(
span,
"relaxed bounds are not permitted in trait object types",
);
gate("trait object types", "trait object types");
return;
}
RelaxedBoundForbiddenReason::SuperTrait => {
if self.tcx.features().more_maybe_bounds() {
return;
}
let mut diag = self.dcx().struct_span_err(
span,
"relaxed bounds are not permitted in supertrait bounds",
);
if let Some(def_id) = trait_ref.trait_def_id()
&& self.tcx.is_lang_item(def_id, hir::LangItem::Sized)
{
diag.note("traits are `?Sized` by default");
}
diag.emit();
gate("supertrait bounds", "traits");
return;
}
RelaxedBoundForbiddenReason::AssocTyBounds
@ -2142,7 +2142,7 @@ impl<'a, 'hir> LoweringContext<'a, 'hir> {
.struct_span_err(span, "this relaxed bound is not permitted here")
.with_note(
"in this context, relaxed bounds are only allowed on \
type parameters defined by the closest item",
type parameters defined on the closest item",
)
.emit();
}

2
tests/ui/feature-gates/feature-gate-more-maybe-bounds.stderr
View file

@ -10,7 +10,7 @@ error: this relaxed bound is not permitted here
LL | trait Trait4 where Self: ?Trait1 {}
| ^^^^^^^
|
= note: in this context, relaxed bounds are only allowed on type parameters defined by the closest item
= note: in this context, relaxed bounds are only allowed on type parameters defined on the closest item
error: relaxed bounds are not permitted in trait object types
--> $DIR/feature-gate-more-maybe-bounds.rs:8:28

6
tests/ui/parser/trait-object-trait-parens.stderr
View file

@ -3,18 +3,24 @@ error: relaxed bounds are not permitted in trait object types
|
LL | let _: Box<(Obj) + (?Sized) + (for<'a> Trait<'a>)>;
| ^^^^^^^^
|
= note: trait object types are not implicitly bounded by `Sized`, so there is nothing to relax
error: relaxed bounds are not permitted in trait object types
--> $DIR/trait-object-trait-parens.rs:13:16
|
LL | let _: Box<?Sized + (for<'a> Trait<'a>) + (Obj)>;
| ^^^^^^
|
= note: trait object types are not implicitly bounded by `Sized`, so there is nothing to relax
error: relaxed bounds are not permitted in trait object types
--> $DIR/trait-object-trait-parens.rs:18:44
|
LL | let _: Box<for<'a> Trait<'a> + (Obj) + (?Sized)>;
| ^^^^^^^^
|
= note: trait object types are not implicitly bounded by `Sized`, so there is nothing to relax
warning: trait objects without an explicit `dyn` are deprecated
--> $DIR/trait-object-trait-parens.rs:8:16

2
tests/ui/sized-hierarchy/default-supertrait.stderr
View file

@ -4,7 +4,7 @@ error: relaxed bounds are not permitted in supertrait bounds
LL | trait NegSized: ?Sized { }
| ^^^^^^
|
= note: traits are `?Sized` by default
= note: traits are not implicitly bounded by `Sized`, so there is nothing to relax
error: relaxed bounds are not permitted in supertrait bounds
--> $DIR/default-supertrait.rs:13:21

6
tests/ui/trait-bounds/more_maybe_bounds.stderr
View file

@ -4,7 +4,7 @@ error: this relaxed bound is not permitted here
LL | fn baz<T>() where T: Iterator<Item: ?Trait1> {}
| ^^^^^^^
|
= note: in this context, relaxed bounds are only allowed on type parameters defined by the closest item
= note: in this context, relaxed bounds are only allowed on type parameters defined on the closest item
error: this relaxed bound is not permitted here
--> $DIR/more_maybe_bounds.rs:29:21
@ -12,7 +12,7 @@ error: this relaxed bound is not permitted here
LL | fn f() where T: ?Trait1 {}
| ^^^^^^^
|
= note: in this context, relaxed bounds are only allowed on type parameters defined by the closest item
= note: in this context, relaxed bounds are only allowed on type parameters defined on the closest item
error: this relaxed bound is not permitted here
--> $DIR/more_maybe_bounds.rs:35:34
@ -20,7 +20,7 @@ error: this relaxed bound is not permitted here
LL | struct S2<T>(T) where for<'a> T: ?Trait5<'a>;
| ^^^^^^^^^^^
|
= note: in this context, relaxed bounds are only allowed on type parameters defined by the closest item
= note: in this context, relaxed bounds are only allowed on type parameters defined on the closest item
error: bound modifier `?` can only be applied to default traits like `Sized`
--> $DIR/more_maybe_bounds.rs:17:20

2
tests/ui/traits/wf-object/only-maybe-bound.stderr
View file

@ -3,6 +3,8 @@ error: relaxed bounds are not permitted in trait object types
|
LL | type _0 = dyn ?Sized;
| ^^^^^^
|
= note: trait object types are not implicitly bounded by `Sized`, so there is nothing to relax
error[E0224]: at least one trait is required for an object type
--> $DIR/only-maybe-bound.rs:3:11

20
tests/ui/unsized/relaxed-bounds-invalid-places.stderr
View file

@ -4,7 +4,7 @@ error: this relaxed bound is not permitted here
LL | struct S1<T>(T) where (T): ?Sized;
| ^^^^^^
|
= note: in this context, relaxed bounds are only allowed on type parameters defined by the closest item
= note: in this context, relaxed bounds are only allowed on type parameters defined on the closest item
error: this relaxed bound is not permitted here
--> $DIR/relaxed-bounds-invalid-places.rs:8:27
@ -12,7 +12,7 @@ error: this relaxed bound is not permitted here
LL | struct S2<T>(T) where u8: ?Sized;
| ^^^^^^
|
= note: in this context, relaxed bounds are only allowed on type parameters defined by the closest item
= note: in this context, relaxed bounds are only allowed on type parameters defined on the closest item
error: this relaxed bound is not permitted here
--> $DIR/relaxed-bounds-invalid-places.rs:10:35
@ -20,7 +20,7 @@ error: this relaxed bound is not permitted here
LL | struct S3<T>(T) where &'static T: ?Sized;
| ^^^^^^
|
= note: in this context, relaxed bounds are only allowed on type parameters defined by the closest item
= note: in this context, relaxed bounds are only allowed on type parameters defined on the closest item
error: this relaxed bound is not permitted here
--> $DIR/relaxed-bounds-invalid-places.rs:14:34
@ -28,7 +28,7 @@ error: this relaxed bound is not permitted here
LL | struct S4<T>(T) where for<'a> T: ?Trait<'a>;
| ^^^^^^^^^^
|
= note: in this context, relaxed bounds are only allowed on type parameters defined by the closest item
= note: in this context, relaxed bounds are only allowed on type parameters defined on the closest item
error: this relaxed bound is not permitted here
--> $DIR/relaxed-bounds-invalid-places.rs:22:21
@ -36,7 +36,7 @@ error: this relaxed bound is not permitted here
LL | fn f() where T: ?Sized {}
| ^^^^^^
|
= note: in this context, relaxed bounds are only allowed on type parameters defined by the closest item
= note: in this context, relaxed bounds are only allowed on type parameters defined on the closest item
error: this relaxed bound is not permitted here
--> $DIR/relaxed-bounds-invalid-places.rs:27:41
@ -44,7 +44,7 @@ error: this relaxed bound is not permitted here
LL | struct S6<T>(T) where T: Iterator<Item: ?Sized>;
| ^^^^^^
|
= note: in this context, relaxed bounds are only allowed on type parameters defined by the closest item
= note: in this context, relaxed bounds are only allowed on type parameters defined on the closest item
error: relaxed bounds are not permitted in supertrait bounds
--> $DIR/relaxed-bounds-invalid-places.rs:29:11
@ -52,25 +52,31 @@ error: relaxed bounds are not permitted in supertrait bounds
LL | trait Tr: ?Sized {}
| ^^^^^^
|
= note: traits are `?Sized` by default
= note: traits are not implicitly bounded by `Sized`, so there is nothing to relax
error: relaxed bounds are not permitted in trait object types
--> $DIR/relaxed-bounds-invalid-places.rs:33:20
|
LL | type O1 = dyn Tr + ?Sized;
| ^^^^^^
|
= note: trait object types are not implicitly bounded by `Sized`, so there is nothing to relax
error: relaxed bounds are not permitted in trait object types
--> $DIR/relaxed-bounds-invalid-places.rs:34:15
|
LL | type O2 = dyn ?Sized + ?Sized + Tr;
| ^^^^^^
|
= note: trait object types are not implicitly bounded by `Sized`, so there is nothing to relax
error: relaxed bounds are not permitted in trait object types
--> $DIR/relaxed-bounds-invalid-places.rs:34:24
|
LL | type O2 = dyn ?Sized + ?Sized + Tr;
| ^^^^^^
|
= note: trait object types are not implicitly bounded by `Sized`, so there is nothing to relax
error: bound modifier `?` can only be applied to `Sized`
--> $DIR/relaxed-bounds-invalid-places.rs:14:34