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Do not suggest borrow that is already there in fully-qualified call

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When encountering `&str::from("value")` do not suggest `&&str::from("value")`.

Fix #132041.
This commit is contained in:
Esteban Küber 2024-11-01 19:00:05 +00:00
parent 076a0a26fd
commit bb74f47327
3 changed files with 40 additions and 0 deletions
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9
compiler/rustc_trait_selection/src/error_reporting/traits/suggestions.rs
View file

@ -1195,6 +1195,15 @@ impl<'a, 'tcx> TypeErrCtxt<'a, 'tcx> {
c @ ObligationCauseCode::WhereClauseInExpr(_, _, hir_id, _)
if self.tcx.hir_span(*hir_id).lo() == span.lo() =>
{
if let hir::Node::Expr(expr) = self.tcx.parent_hir_node(*hir_id)
&& let hir::ExprKind::Call(base, _) = expr.kind
&& let hir::ExprKind::Path(hir::QPath::TypeRelative(ty, _)) = base.kind
&& ty.span == span
{
// Do not suggest borrowing when we already do so. This would happen with
// `let _ = &str::from("");` where the expression corresponds to the `str`.
return false;
}
c
}
c if matches!(

5
tests/ui/suggestions/dont-suggest-borrowing-existing-borrow.rs Normal file
View file

@ -0,0 +1,5 @@
fn main() {
let _ = &str::from("value");
//~^ ERROR the trait bound `str: From<_>` is not satisfied
//~| ERROR the size for values of type `str` cannot be known at compilation time
}

26
tests/ui/suggestions/dont-suggest-borrowing-existing-borrow.stderr Normal file
View file

@ -0,0 +1,26 @@
error[E0277]: the trait bound `str: From<_>` is not satisfied
--> $DIR/dont-suggest-borrowing-existing-borrow.rs:2:14
|
LL | let _ = &str::from("value");
| ^^^ the trait `From<_>` is not implemented for `str`
|
= help: the following other types implement trait `From<T>`:
`String` implements `From<&String>`
`String` implements `From<&mut str>`
`String` implements `From<&str>`
`String` implements `From<Box<str>>`
`String` implements `From<Cow<'_, str>>`
`String` implements `From<char>`
error[E0277]: the size for values of type `str` cannot be known at compilation time
--> $DIR/dont-suggest-borrowing-existing-borrow.rs:2:14
|
LL | let _ = &str::from("value");
| ^^^^^^^^^^^^^^^^^^ doesn't have a size known at compile-time
|
= help: the trait `Sized` is not implemented for `str`
= note: the return type of a function must have a statically known size
error: aborting due to 2 previous errors
For more information about this error, try `rustc --explain E0277`.