2ab8480605
This subsumes the suggestions to borrow arguments with `AsRef`/`Borrow` bounds and those to borrow arguments with `Fn` and `FnMut` bounds. It works for other traits implemented on references as well, such as `std::io::Read`, `std::io::Write`, and `core::fmt::Write`. Incidentally, by making the logic for suggesting borrowing closures general, this removes some spurious suggestions to mutably borrow `FnMut` closures in assignments, as well as an unhelpful suggestion to add a `Clone` constraint to an `impl Fn` argument.
62 lines
2 KiB
Text
62 lines
2 KiB
Text
error[E0382]: use of moved value: `f`
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--> $DIR/borrow-closures-instead-of-move.rs:3:22
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LL | fn takes_fn(f: impl Fn()) {
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| - move occurs because `f` has type `impl Fn()`, which does not implement the `Copy` trait
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LL | loop {
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| ---- inside of this loop
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LL | takes_fnonce(f);
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| ^ value moved here, in previous iteration of loop
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help: consider borrowing `f`
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LL | takes_fnonce(&f);
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| +
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error[E0382]: use of moved value: `m`
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--> $DIR/borrow-closures-instead-of-move.rs:14:18
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LL | fn takes_fn_mut(m: impl FnMut()) {
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| - move occurs because `m` has type `impl FnMut()`, which does not implement the `Copy` trait
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LL | if maybe() {
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LL | takes_fnonce(m);
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| - value moved here
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...
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LL | takes_fnonce(m);
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| ^ value used here after move
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help: if `impl FnMut()` implemented `Clone`, you could clone the value
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--> $DIR/borrow-closures-instead-of-move.rs:9:20
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LL | fn takes_fn_mut(m: impl FnMut()) {
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| ^^^^^^^^^^^^ consider constraining this type parameter with `Clone`
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LL | if maybe() {
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LL | takes_fnonce(m);
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| - you could clone this value
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help: consider mutably borrowing `m`
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LL | takes_fnonce(&mut m);
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| ++++
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error[E0382]: borrow of moved value: `closure`
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--> $DIR/borrow-closures-instead-of-move.rs:25:5
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LL | takes_fnonce(closure);
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| ------- value moved here
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LL |
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LL | closure();
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| ^^^^^^^ value borrowed here after move
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note: closure cannot be moved more than once as it is not `Copy` due to moving the variable `x` out of its environment
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--> $DIR/borrow-closures-instead-of-move.rs:21:9
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LL | x += 1;
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| ^
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help: consider mutably borrowing `closure`
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LL | takes_fnonce(&mut closure);
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| ++++
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error: aborting due to 3 previous errors
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For more information about this error, try `rustc --explain E0382`.
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