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9e153ccd45
Detect calls to .clone() on T: !Clone types on borrowck errors
When encountering a lifetime error on a type that *holds* a type that doesn't implement `Clone`, explore the item's body for potential calls to `.clone()` that are only cloning the reference `&T` instead of `T` because `T: !Clone`. If we find this, suggest `T: Clone`.
```
error[E0502]: cannot borrow `*list` as mutable because it is also borrowed as immutable
--> $DIR/clone-on-ref.rs:7:5
|
LL | for v in list.iter() {
| ---- immutable borrow occurs here
LL | cloned_items.push(v.clone())
| ------- this call doesn't do anything, the result is still `&T` because `T` doesn't implement `Clone`
LL | }
LL | list.push(T::default());
| ^^^^^^^^^^^^^^^^^^^^^^^ mutable borrow occurs here
LL |
LL | drop(cloned_items);
| ------------ immutable borrow later used here
|
help: consider further restricting this bound
|
LL | fn foo<T: Default + Clone>(list: &mut Vec<T>) {
| +++++++
```
```
error[E0505]: cannot move out of `x` because it is borrowed
--> $DIR/clone-on-ref.rs:23:10
|
LL | fn qux(x: A) {
| - binding `x` declared here
LL | let a = &x;
| -- borrow of `x` occurs here
LL | let b = a.clone();
| ------- this call doesn't do anything, the result is still `&A` because `A` doesn't implement `Clone`
LL | drop(x);
| ^ move out of `x` occurs here
LL |
LL | println!("{b:?}");
| ----- borrow later used here
|
help: consider annotating `A` with `#[derive(Clone)]`
|
LL + #[derive(Clone)]
LL | struct A;
|
```
Fix #48677.
|
||
|---|---|---|
| .. | ||
| auxiliary | ||
| bindings-after-at | ||
| move-ref-patterns | ||
| usefulness | ||
| byte-string-inference.rs | ||
| complexity_limit.rs | ||
| complexity_limit.stderr | ||
| for-loop-bad-item.rs | ||
| for-loop-bad-item.stderr | ||
| ignore-all-the-things.rs | ||
| incorrect-placement-of-pattern-modifiers.fixed | ||
| incorrect-placement-of-pattern-modifiers.rs | ||
| incorrect-placement-of-pattern-modifiers.stderr | ||
| integer-range-binding.rs | ||
| issue-6449.rs | ||
| issue-8351-1.rs | ||
| issue-8351-2.rs | ||
| issue-10392.rs | ||
| issue-11577.rs | ||
| issue-12582.rs | ||
| issue-14221.rs | ||
| issue-14221.stderr | ||
| issue-15080.rs | ||
| issue-17718-patterns.rs | ||
| issue-17718-patterns.stderr | ||
| issue-22546.rs | ||
| issue-22546.stderr | ||
| issue-27320.rs | ||
| issue-28992-empty.rs | ||
| issue-28992-empty.stderr | ||
| issue-52240.rs | ||
| issue-52240.stderr | ||
| issue-66270-pat-struct-parser-recovery.rs | ||
| issue-66270-pat-struct-parser-recovery.stderr | ||
| issue-67037-pat-tup-scrut-ty-diff-less-fields.rs | ||
| issue-67037-pat-tup-scrut-ty-diff-less-fields.stderr | ||
| issue-67776-match-same-name-enum-variant-refs.rs | ||
| issue-67776-match-same-name-enum-variant-refs.stderr | ||
| issue-68393-let-pat-assoc-constant.rs | ||
| issue-68393-let-pat-assoc-constant.stderr | ||
| issue-72565.rs | ||
| issue-72565.stderr | ||
| issue-72574-1.rs | ||
| issue-72574-1.stderr | ||
| issue-72574-2.rs | ||
| issue-72574-2.stderr | ||
| issue-74539.rs | ||
| issue-74539.stderr | ||
| issue-74702.rs | ||
| issue-74702.stderr | ||
| issue-74954.rs | ||
| issue-80186-mut-binding-help-suggestion.rs | ||
| issue-80186-mut-binding-help-suggestion.stderr | ||
| issue-88074-pat-range-type-inference-err.rs | ||
| issue-88074-pat-range-type-inference-err.stderr | ||
| issue-88074-pat-range-type-inference.rs | ||
| issue-92074-macro-ice.rs | ||
| issue-92074-macro-ice.stderr | ||
| issue-94866.rs | ||
| issue-94866.stderr | ||
| issue-95878.rs | ||
| issue-95878.stderr | ||
| issue-106552.rs | ||
| issue-106552.stderr | ||
| issue-106862.fixed | ||
| issue-106862.rs | ||
| issue-106862.stderr | ||
| issue-110508.rs | ||
| issue-114896.rs | ||
| issue-114896.stderr | ||
| issue-115599.rs | ||
| issue-115599.stderr | ||
| issue-117626.rs | ||
| non-constant-in-const-path.rs | ||
| non-constant-in-const-path.stderr | ||
| non-structural-match-types.rs | ||
| non-structural-match-types.stderr | ||
| pat-shadow-in-nested-binding.rs | ||
| pat-shadow-in-nested-binding.stderr | ||
| pat-struct-field-expr-has-type.rs | ||
| pat-struct-field-expr-has-type.stderr | ||
| pat-tuple-bad-type.rs | ||
| pat-tuple-bad-type.stderr | ||
| pat-tuple-field-count-cross.rs | ||
| pat-tuple-field-count-cross.stderr | ||
| pat-tuple-overfield.rs | ||
| pat-tuple-overfield.stderr | ||
| pat-tuple-underfield.rs | ||
| pat-tuple-underfield.stderr | ||
| pat-type-err-formal-param.rs | ||
| pat-type-err-formal-param.stderr | ||
| pat-type-err-let-stmt.rs | ||
| pat-type-err-let-stmt.stderr | ||
| patkind-litrange-no-expr.rs | ||
| patkind-litrange-no-expr.stderr | ||
| pattern-bad-ref-box-order.fixed | ||
| pattern-bad-ref-box-order.rs | ||
| pattern-bad-ref-box-order.stderr | ||
| pattern-binding-disambiguation.rs | ||
| pattern-binding-disambiguation.stderr | ||
| pattern-error-continue.rs | ||
| pattern-error-continue.stderr | ||
| pattern-ident-path-generics.rs | ||
| pattern-ident-path-generics.stderr | ||
| pattern-tyvar-2.rs | ||
| pattern-tyvar-2.stderr | ||
| pattern-tyvar.rs | ||
| pattern-tyvar.stderr | ||
| range-pattern-meant-to-be-slice-rest-pattern.rs | ||
| range-pattern-meant-to-be-slice-rest-pattern.stderr | ||
| rest-pat-semantic-disallowed.rs | ||
| rest-pat-semantic-disallowed.stderr | ||
| rest-pat-syntactic.rs | ||
| rest-pat-syntactic.stderr | ||
| size-and-align.rs | ||
| slice-array-infer.rs | ||
| slice-pattern-refutable.rs | ||
| slice-pattern-refutable.stderr | ||
| slice-patterns-ambiguity.rs | ||
| slice-patterns-ambiguity.stderr | ||
| slice-patterns-irrefutable.rs | ||
| slice-patterns-irrefutable.stderr | ||
| slice-patterns-nested.rs | ||
| suggest-adding-appropriate-missing-pattern-excluding-comments.fixed | ||
| suggest-adding-appropriate-missing-pattern-excluding-comments.rs | ||
| suggest-adding-appropriate-missing-pattern-excluding-comments.stderr | ||