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Fix malformed suggestion for repeated maybe unsized bounds

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This commit is contained in:
Gurinder Singh 2024-07-14 17:46:25 +05:30
parent b1de36ff34
commit e13eb37eeb
4 changed files with 295 additions and 29 deletions
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69
compiler/rustc_middle/src/ty/diagnostics.rs
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@ -188,31 +188,60 @@ fn suggest_changing_unsized_bound(
continue;
};
for (pos, bound) in predicate.bounds.iter().enumerate() {
let hir::GenericBound::Trait(poly, hir::TraitBoundModifier::Maybe) = bound else {
continue;
};
if poly.trait_ref.trait_def_id() != def_id {
continue;
}
if predicate.origin == PredicateOrigin::ImplTrait && predicate.bounds.len() == 1 {
// For `impl ?Sized` with no other bounds, suggest `impl Sized` instead.
let bound_span = bound.span();
if bound_span.can_be_used_for_suggestions() {
let question_span = bound_span.with_hi(bound_span.lo() + BytePos(1));
suggestions.push((
let unsized_bounds = predicate
.bounds
.iter()
.enumerate()
.filter(|(_, bound)| {
if let hir::GenericBound::Trait(poly, hir::TraitBoundModifier::Maybe) = bound
&& poly.trait_ref.trait_def_id() == def_id
{
true
} else {
false
}
})
.collect::<Vec<_>>();
if unsized_bounds.is_empty() {
continue;
}
let mut push_suggestion = |sp, msg| suggestions.push((sp, String::new(), msg));
if predicate.bounds.len() == unsized_bounds.len() {
// All the bounds are unsized bounds, e.g.
// `T: ?Sized + ?Sized` or `_: impl ?Sized + ?Sized`,
// so in this case:
// - if it's an impl trait predicate suggest changing the
// the first bound to sized and removing the rest
// - Otherwise simply suggest removing the entire predicate
if predicate.origin == PredicateOrigin::ImplTrait {
let first_bound = unsized_bounds[0].1;
let first_bound_span = first_bound.span();
if first_bound_span.can_be_used_for_suggestions() {
let question_span =
first_bound_span.with_hi(first_bound_span.lo() + BytePos(1));
push_suggestion(
question_span,
String::new(),
SuggestChangingConstraintsMessage::ReplaceMaybeUnsizedWithSized,
));
);
for (pos, _) in unsized_bounds.iter().skip(1) {
let sp = generics.span_for_bound_removal(where_pos, *pos);
push_suggestion(sp, SuggestChangingConstraintsMessage::RemoveMaybeUnsized);
}
}
} else {
let sp = generics.span_for_predicate_removal(where_pos);
push_suggestion(sp, SuggestChangingConstraintsMessage::RemoveMaybeUnsized);
}
} else {
// Some of the bounds are other than unsized.
// So push separate removal suggestion for each unsized bound
for (pos, _) in unsized_bounds {
let sp = generics.span_for_bound_removal(where_pos, pos);
suggestions.push((
sp,
String::new(),
SuggestChangingConstraintsMessage::RemoveMaybeUnsized,
));
push_suggestion(sp, SuggestChangingConstraintsMessage::RemoveMaybeUnsized);
}
}
}