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Account for '_ in lifetime suggestion

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This commit is contained in:
Esteban Küber 2023-11-15 18:00:43 +00:00
parent 2a92d820c7
commit 85f26ade8d
3 changed files with 35 additions and 4 deletions
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19
compiler/rustc_resolve/src/late/diagnostics.rs
View file

@ -3079,6 +3079,7 @@ impl<'a: 'ast, 'ast, 'tcx> LateResolutionVisitor<'a, '_, 'ast, 'tcx> {
} else {
"instead, you are more likely to want"
};
let mut owned_sugg = lt.kind == MissingLifetimeKind::Ampersand;
let mut sugg = vec![(lt.span, String::new())];
if let Some((kind, _span)) =
self.diagnostic_metadata.current_function
@ -3092,6 +3093,17 @@ impl<'a: 'ast, 'ast, 'tcx> LateResolutionVisitor<'a, '_, 'ast, 'tcx> {
};
lt_finder.visit_ty(&ty);
if let [Ty { span, kind: TyKind::Ref(_, mut_ty), ..}]
= &lt_finder.seen[..]
{
// We might have a situation like
// fn g(mut x: impl Iterator<Item = &'_ ()>) -> Option<&'_ ()>
// but `lt.span` only points at `'_`, so to suggest `-> Option<()>`
// we need to find a more accurate span to end up with
// fn g<'a>(mut x: impl Iterator<Item = &'_ ()>) -> Option<()>
sugg = vec![(span.with_hi(mut_ty.ty.span.lo()), String::new())];
owned_sugg = true;
}
if let Some(ty) = lt_finder.found {
if let TyKind::Path(None, Path { segments, .. }) = &ty.kind
&& segments.len() == 1
@ -3101,8 +3113,7 @@ impl<'a: 'ast, 'ast, 'tcx> LateResolutionVisitor<'a, '_, 'ast, 'tcx> {
sugg = vec![
(lt.span.with_hi(ty.span.hi()), "String".to_string()),
];
}
if let TyKind::Slice(inner_ty) = &ty.kind {
} else if let TyKind::Slice(inner_ty) = &ty.kind {
// Don't suggest `-> [T]`, suggest `-> Vec<T>`.
sugg = vec![
(lt.span.with_hi(inner_ty.span.lo()), "Vec<".to_string()),
@ -3110,8 +3121,8 @@ impl<'a: 'ast, 'ast, 'tcx> LateResolutionVisitor<'a, '_, 'ast, 'tcx> {
];
}
}
};
if lt.kind == MissingLifetimeKind::Ampersand {
}
if owned_sugg {
err.multipart_suggestion_verbose(
format!("{pre} to return an owned value"),
sugg,

10
tests/ui/suggestions/impl-trait-missing-lifetime-gated.stderr
View file

@ -55,6 +55,11 @@ help: consider introducing a named lifetime parameter
|
LL | fn g<'a>(mut x: impl Iterator<Item = &'a ()>) -> Option<&'a ()> { x.next() }
| ++++ ~~~ ~~~
help: alternatively, you might want to return an owned value
|
LL - fn g(mut x: impl Iterator<Item = &'_ ()>) -> Option<&'_ ()> { x.next() }
LL + fn g(mut x: impl Iterator<Item = &'_ ()>) -> Option<()> { x.next() }
|
error[E0106]: missing lifetime specifier
--> $DIR/impl-trait-missing-lifetime-gated.rs:37:64
@ -71,6 +76,11 @@ help: consider introducing a named lifetime parameter
|
LL | async fn i<'a>(mut x: impl Iterator<Item = &'a ()>) -> Option<&'a ()> { x.next() }
| ++++ ~~~ ~~~
help: alternatively, you might want to return an owned value
|
LL - async fn i(mut x: impl Iterator<Item = &'_ ()>) -> Option<&'_ ()> { x.next() }
LL + async fn i(mut x: impl Iterator<Item = &'_ ()>) -> Option<()> { x.next() }
|
error[E0106]: missing lifetime specifier
--> $DIR/impl-trait-missing-lifetime-gated.rs:47:37

10
tests/ui/suggestions/impl-trait-missing-lifetime.stderr
View file

@ -13,6 +13,11 @@ help: consider introducing a named lifetime parameter
|
LL | fn g<'a>(mut x: impl Iterator<Item = &'a ()>) -> Option<&'a ()> { x.next() }
| ++++ ~~~ ~~~
help: alternatively, you might want to return an owned value
|
LL - fn g(mut x: impl Iterator<Item = &'_ ()>) -> Option<&'_ ()> { x.next() }
LL + fn g(mut x: impl Iterator<Item = &'_ ()>) -> Option<()> { x.next() }
|
error[E0106]: missing lifetime specifier
--> $DIR/impl-trait-missing-lifetime.rs:16:60
@ -29,6 +34,11 @@ help: consider introducing a named lifetime parameter
|
LL | async fn i<'a>(mut x: impl Iterator<Item = &'a ()>) -> Option<&'a ()> { x.next() }
| ++++ ~~~ ~~~
help: alternatively, you might want to return an owned value
|
LL - async fn i(mut x: impl Iterator<Item = &'_ ()>) -> Option<&'_ ()> { x.next() }
LL + async fn i(mut x: impl Iterator<Item = &'_ ()>) -> Option<()> { x.next() }
|
error: lifetime may not live long enough
--> $DIR/impl-trait-missing-lifetime.rs:16:69