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| author | Esteban Küber <esteban@kuber.com.ar> | 2025-07-28 02:01:46 +0000 |
|---|---|---|
| committer | Esteban Küber <esteban@kuber.com.ar> | 2025-08-10 19:22:49 +0000 |
| commit | 1aa5668d20d53976860d141a66aa727e425e1079 (patch) | |
| tree | a03a92171b4937e65ff1c5812163134ab957df59 /tests/ui/suggestions | |
| parent | 18eeac04fc5c2a4c4a8020dbdf1c652077ad0e4e (diff) | |
| download | rust-1aa5668d20d53976860d141a66aa727e425e1079.tar.gz rust-1aa5668d20d53976860d141a66aa727e425e1079.zip | |
Point at the `Fn()` or `FnMut()` bound that coerced a closure, which caused a move error
When encountering a move error involving a closure because the captured value isn't `Copy`, and the obligation comes from a bound on a type parameter that requires `Fn` or `FnMut`, we point at it and explain that an `FnOnce` wouldn't cause the move error.
```
error[E0507]: cannot move out of `foo`, a captured variable in an `Fn` closure
--> f111.rs:15:25
|
14 | fn do_stuff(foo: Option<Foo>) {
| --- ----------- move occurs because `foo` has type `Option<Foo>`, which does not implement the `Copy` trait
| |
| captured outer variable
15 | require_fn_trait(|| async {
| -- ^^^^^ `foo` is moved here
| |
| captured by this `Fn` closure
16 | if foo.map_or(false, |f| f.foo()) {
| --- variable moved due to use in coroutine
|
help: `Fn` and `FnMut` closures require captured values to be able to be consumed multiple times, but an `FnOnce` consume them only once
--> f111.rs:12:53
|
12 | fn require_fn_trait<F: Future<Output = ()>>(_: impl Fn() -> F) {}
| ^^^^^^^^^
help: consider cloning the value if the performance cost is acceptable
|
16 | if foo.clone().map_or(false, |f| f.foo()) {
| ++++++++
```
Diffstat (limited to 'tests/ui/suggestions')
4 files changed, 170 insertions, 21 deletions
diff --git a/tests/ui/suggestions/dont-suggest-ref/move-into-closure.rs b/tests/ui/suggestions/dont-suggest-ref/move-into-closure.rs index 44eac3691a3..0154810f564 100644 --- a/tests/ui/suggestions/dont-suggest-ref/move-into-closure.rs +++ b/tests/ui/suggestions/dont-suggest-ref/move-into-closure.rs @@ -11,8 +11,29 @@ struct X(Y); struct Y; fn consume_fn<F: Fn()>(_f: F) { } +//~^ HELP `Fn` and `FnMut` closures +//~| HELP `Fn` and `FnMut` closures +//~| HELP `Fn` and `FnMut` closures +//~| HELP `Fn` and `FnMut` closures +//~| HELP `Fn` and `FnMut` closures +//~| HELP `Fn` and `FnMut` closures +//~| HELP `Fn` and `FnMut` closures +//~| HELP `Fn` and `FnMut` closures +//~| HELP `Fn` and `FnMut` closures +//~| HELP `Fn` and `FnMut` closures fn consume_fnmut<F: FnMut()>(_f: F) { } +//~^ HELP `Fn` and `FnMut` closures +//~| HELP `Fn` and `FnMut` closures +//~| HELP `Fn` and `FnMut` closures +//~| HELP `Fn` and `FnMut` closures +//~| HELP `Fn` and `FnMut` closures +//~| HELP `Fn` and `FnMut` closures +//~| HELP `Fn` and `FnMut` closures +//~| HELP `Fn` and `FnMut` closures +//~| HELP `Fn` and `FnMut` closures +//~| HELP `Fn` and `FnMut` closures +//~| HELP `Fn` and `FnMut` closures pub fn main() { } diff --git a/tests/ui/suggestions/dont-suggest-ref/move-into-closure.stderr b/tests/ui/suggestions/dont-suggest-ref/move-into-closure.stderr index edda2cbc735..d9ed25983d6 100644 --- a/tests/ui/suggestions/dont-suggest-ref/move-into-closure.stderr +++ b/tests/ui/suggestions/dont-suggest-ref/move-into-closure.stderr @@ -1,5 +1,5 @@ error[E0507]: cannot move out of `x.0`, as `x` is a captured variable in an `Fn` closure - --> $DIR/move-into-closure.rs:28:21 + --> $DIR/move-into-closure.rs:49:21 | LL | let x = X(Y); | - captured outer variable @@ -12,13 +12,18 @@ LL | let X(_t) = x; | data moved here | move occurs because `_t` has type `Y`, which does not implement the `Copy` trait | +help: `Fn` and `FnMut` closures require captured values to be able to be consumed multiple times, but an `FnOnce` consume them only once + --> $DIR/move-into-closure.rs:13:18 + | +LL | fn consume_fn<F: Fn()>(_f: F) { } + | ^^^^ help: consider borrowing here | LL | let X(_t) = &x; | + error[E0507]: cannot move out of `e.0`, as `e` is a captured variable in an `Fn` closure - --> $DIR/move-into-closure.rs:31:34 + --> $DIR/move-into-closure.rs:52:34 | LL | let e = Either::One(X(Y)); | - captured outer variable @@ -32,13 +37,18 @@ LL | if let Either::One(_t) = e { } | data moved here | move occurs because `_t` has type `X`, which does not implement the `Copy` trait | +help: `Fn` and `FnMut` closures require captured values to be able to be consumed multiple times, but an `FnOnce` consume them only once + --> $DIR/move-into-closure.rs:13:18 + | +LL | fn consume_fn<F: Fn()>(_f: F) { } + | ^^^^ help: consider borrowing here | LL | if let Either::One(_t) = &e { } | + error[E0507]: cannot move out of `e.0`, as `e` is a captured variable in an `Fn` closure - --> $DIR/move-into-closure.rs:34:37 + --> $DIR/move-into-closure.rs:55:37 | LL | let e = Either::One(X(Y)); | - captured outer variable @@ -52,13 +62,18 @@ LL | while let Either::One(_t) = e { } | data moved here | move occurs because `_t` has type `X`, which does not implement the `Copy` trait | +help: `Fn` and `FnMut` closures require captured values to be able to be consumed multiple times, but an `FnOnce` consume them only once + --> $DIR/move-into-closure.rs:13:18 + | +LL | fn consume_fn<F: Fn()>(_f: F) { } + | ^^^^ help: consider borrowing here | LL | while let Either::One(_t) = &e { } | + error[E0507]: cannot move out of `e.0`, as `e` is a captured variable in an `Fn` closure - --> $DIR/move-into-closure.rs:37:15 + --> $DIR/move-into-closure.rs:58:15 | LL | let e = Either::One(X(Y)); | - captured outer variable @@ -75,13 +90,18 @@ LL | Either::One(_t) | data moved here | move occurs because `_t` has type `X`, which does not implement the `Copy` trait | +help: `Fn` and `FnMut` closures require captured values to be able to be consumed multiple times, but an `FnOnce` consume them only once + --> $DIR/move-into-closure.rs:13:18 + | +LL | fn consume_fn<F: Fn()>(_f: F) { } + | ^^^^ help: consider borrowing here | LL | match &e { | + error[E0507]: cannot move out of `e.0`, as `e` is a captured variable in an `Fn` closure - --> $DIR/move-into-closure.rs:43:15 + --> $DIR/move-into-closure.rs:64:15 | LL | let e = Either::One(X(Y)); | - captured outer variable @@ -98,13 +118,18 @@ LL | Either::One(_t) => (), | data moved here | move occurs because `_t` has type `X`, which does not implement the `Copy` trait | +help: `Fn` and `FnMut` closures require captured values to be able to be consumed multiple times, but an `FnOnce` consume them only once + --> $DIR/move-into-closure.rs:13:18 + | +LL | fn consume_fn<F: Fn()>(_f: F) { } + | ^^^^ help: consider borrowing here | LL | match &e { | + error[E0507]: cannot move out of `x.0`, as `x` is a captured variable in an `Fn` closure - --> $DIR/move-into-closure.rs:51:25 + --> $DIR/move-into-closure.rs:72:25 | LL | let x = X(Y); | - captured outer variable @@ -118,13 +143,18 @@ LL | let X(mut _t) = x; | data moved here | move occurs because `_t` has type `Y`, which does not implement the `Copy` trait | +help: `Fn` and `FnMut` closures require captured values to be able to be consumed multiple times, but an `FnOnce` consume them only once + --> $DIR/move-into-closure.rs:13:18 + | +LL | fn consume_fn<F: Fn()>(_f: F) { } + | ^^^^ help: consider borrowing here | LL | let X(mut _t) = &x; | + error[E0507]: cannot move out of `em.0`, as `em` is a captured variable in an `Fn` closure - --> $DIR/move-into-closure.rs:54:38 + --> $DIR/move-into-closure.rs:75:38 | LL | let mut em = Either::One(X(Y)); | ------ captured outer variable @@ -138,13 +168,18 @@ LL | if let Either::One(mut _t) = em { } | data moved here | move occurs because `_t` has type `X`, which does not implement the `Copy` trait | +help: `Fn` and `FnMut` closures require captured values to be able to be consumed multiple times, but an `FnOnce` consume them only once + --> $DIR/move-into-closure.rs:13:18 + | +LL | fn consume_fn<F: Fn()>(_f: F) { } + | ^^^^ help: consider borrowing here | LL | if let Either::One(mut _t) = &em { } | + error[E0507]: cannot move out of `em.0`, as `em` is a captured variable in an `Fn` closure - --> $DIR/move-into-closure.rs:57:41 + --> $DIR/move-into-closure.rs:78:41 | LL | let mut em = Either::One(X(Y)); | ------ captured outer variable @@ -158,13 +193,18 @@ LL | while let Either::One(mut _t) = em { } | data moved here | move occurs because `_t` has type `X`, which does not implement the `Copy` trait | +help: `Fn` and `FnMut` closures require captured values to be able to be consumed multiple times, but an `FnOnce` consume them only once + --> $DIR/move-into-closure.rs:13:18 + | +LL | fn consume_fn<F: Fn()>(_f: F) { } + | ^^^^ help: consider borrowing here | LL | while let Either::One(mut _t) = &em { } | + error[E0507]: cannot move out of `em.0`, as `em` is a captured variable in an `Fn` closure - --> $DIR/move-into-closure.rs:60:15 + --> $DIR/move-into-closure.rs:81:15 | LL | let mut em = Either::One(X(Y)); | ------ captured outer variable @@ -181,13 +221,18 @@ LL | Either::One(mut _t) | data moved here | move occurs because `_t` has type `X`, which does not implement the `Copy` trait | +help: `Fn` and `FnMut` closures require captured values to be able to be consumed multiple times, but an `FnOnce` consume them only once + --> $DIR/move-into-closure.rs:13:18 + | +LL | fn consume_fn<F: Fn()>(_f: F) { } + | ^^^^ help: consider borrowing here | LL | match &em { | + error[E0507]: cannot move out of `em.0`, as `em` is a captured variable in an `Fn` closure - --> $DIR/move-into-closure.rs:66:15 + --> $DIR/move-into-closure.rs:87:15 | LL | let mut em = Either::One(X(Y)); | ------ captured outer variable @@ -204,13 +249,18 @@ LL | Either::One(mut _t) => (), | data moved here | move occurs because `_t` has type `X`, which does not implement the `Copy` trait | +help: `Fn` and `FnMut` closures require captured values to be able to be consumed multiple times, but an `FnOnce` consume them only once + --> $DIR/move-into-closure.rs:13:18 + | +LL | fn consume_fn<F: Fn()>(_f: F) { } + | ^^^^ help: consider borrowing here | LL | match &em { | + error[E0507]: cannot move out of `x.0`, as `x` is a captured variable in an `FnMut` closure - --> $DIR/move-into-closure.rs:85:21 + --> $DIR/move-into-closure.rs:106:21 | LL | let x = X(Y); | - captured outer variable @@ -223,13 +273,18 @@ LL | let X(_t) = x; | data moved here | move occurs because `_t` has type `Y`, which does not implement the `Copy` trait | +help: `Fn` and `FnMut` closures require captured values to be able to be consumed multiple times, but an `FnOnce` consume them only once + --> $DIR/move-into-closure.rs:25:21 + | +LL | fn consume_fnmut<F: FnMut()>(_f: F) { } + | ^^^^^^^ help: consider borrowing here | LL | let X(_t) = &x; | + error[E0507]: cannot move out of `e.0`, as `e` is a captured variable in an `FnMut` closure - --> $DIR/move-into-closure.rs:88:34 + --> $DIR/move-into-closure.rs:109:34 | LL | let e = Either::One(X(Y)); | - captured outer variable @@ -243,13 +298,18 @@ LL | if let Either::One(_t) = e { } | data moved here | move occurs because `_t` has type `X`, which does not implement the `Copy` trait | +help: `Fn` and `FnMut` closures require captured values to be able to be consumed multiple times, but an `FnOnce` consume them only once + --> $DIR/move-into-closure.rs:25:21 + | +LL | fn consume_fnmut<F: FnMut()>(_f: F) { } + | ^^^^^^^ help: consider borrowing here | LL | if let Either::One(_t) = &e { } | + error[E0507]: cannot move out of `e.0`, as `e` is a captured variable in an `FnMut` closure - --> $DIR/move-into-closure.rs:91:37 + --> $DIR/move-into-closure.rs:112:37 | LL | let e = Either::One(X(Y)); | - captured outer variable @@ -263,13 +323,18 @@ LL | while let Either::One(_t) = e { } | data moved here | move occurs because `_t` has type `X`, which does not implement the `Copy` trait | +help: `Fn` and `FnMut` closures require captured values to be able to be consumed multiple times, but an `FnOnce` consume them only once + --> $DIR/move-into-closure.rs:25:21 + | +LL | fn consume_fnmut<F: FnMut()>(_f: F) { } + | ^^^^^^^ help: consider borrowing here | LL | while let Either::One(_t) = &e { } | + error[E0507]: cannot move out of `e.0`, as `e` is a captured variable in an `FnMut` closure - --> $DIR/move-into-closure.rs:94:15 + --> $DIR/move-into-closure.rs:115:15 | LL | let e = Either::One(X(Y)); | - captured outer variable @@ -286,13 +351,18 @@ LL | Either::One(_t) | data moved here | move occurs because `_t` has type `X`, which does not implement the `Copy` trait | +help: `Fn` and `FnMut` closures require captured values to be able to be consumed multiple times, but an `FnOnce` consume them only once + --> $DIR/move-into-closure.rs:25:21 + | +LL | fn consume_fnmut<F: FnMut()>(_f: F) { } + | ^^^^^^^ help: consider borrowing here | LL | match &e { | + error[E0507]: cannot move out of `e.0`, as `e` is a captured variable in an `FnMut` closure - --> $DIR/move-into-closure.rs:100:15 + --> $DIR/move-into-closure.rs:121:15 | LL | let e = Either::One(X(Y)); | - captured outer variable @@ -309,13 +379,18 @@ LL | Either::One(_t) => (), | data moved here | move occurs because `_t` has type `X`, which does not implement the `Copy` trait | +help: `Fn` and `FnMut` closures require captured values to be able to be consumed multiple times, but an `FnOnce` consume them only once + --> $DIR/move-into-closure.rs:25:21 + | +LL | fn consume_fnmut<F: FnMut()>(_f: F) { } + | ^^^^^^^ help: consider borrowing here | LL | match &e { | + error[E0507]: cannot move out of `x.0`, as `x` is a captured variable in an `FnMut` closure - --> $DIR/move-into-closure.rs:108:25 + --> $DIR/move-into-closure.rs:129:25 | LL | let x = X(Y); | - captured outer variable @@ -329,13 +404,18 @@ LL | let X(mut _t) = x; | data moved here | move occurs because `_t` has type `Y`, which does not implement the `Copy` trait | +help: `Fn` and `FnMut` closures require captured values to be able to be consumed multiple times, but an `FnOnce` consume them only once + --> $DIR/move-into-closure.rs:25:21 + | +LL | fn consume_fnmut<F: FnMut()>(_f: F) { } + | ^^^^^^^ help: consider borrowing here | LL | let X(mut _t) = &x; | + error[E0507]: cannot move out of `em.0`, as `em` is a captured variable in an `FnMut` closure - --> $DIR/move-into-closure.rs:111:38 + --> $DIR/move-into-closure.rs:132:38 | LL | let mut em = Either::One(X(Y)); | ------ captured outer variable @@ -349,13 +429,18 @@ LL | if let Either::One(mut _t) = em { } | data moved here | move occurs because `_t` has type `X`, which does not implement the `Copy` trait | +help: `Fn` and `FnMut` closures require captured values to be able to be consumed multiple times, but an `FnOnce` consume them only once + --> $DIR/move-into-closure.rs:25:21 + | +LL | fn consume_fnmut<F: FnMut()>(_f: F) { } + | ^^^^^^^ help: consider borrowing here | LL | if let Either::One(mut _t) = &em { } | + error[E0507]: cannot move out of `em.0`, as `em` is a captured variable in an `FnMut` closure - --> $DIR/move-into-closure.rs:114:41 + --> $DIR/move-into-closure.rs:135:41 | LL | let mut em = Either::One(X(Y)); | ------ captured outer variable @@ -369,13 +454,18 @@ LL | while let Either::One(mut _t) = em { } | data moved here | move occurs because `_t` has type `X`, which does not implement the `Copy` trait | +help: `Fn` and `FnMut` closures require captured values to be able to be consumed multiple times, but an `FnOnce` consume them only once + --> $DIR/move-into-closure.rs:25:21 + | +LL | fn consume_fnmut<F: FnMut()>(_f: F) { } + | ^^^^^^^ help: consider borrowing here | LL | while let Either::One(mut _t) = &em { } | + error[E0507]: cannot move out of `em.0`, as `em` is a captured variable in an `FnMut` closure - --> $DIR/move-into-closure.rs:117:15 + --> $DIR/move-into-closure.rs:138:15 | LL | let mut em = Either::One(X(Y)); | ------ captured outer variable @@ -392,13 +482,18 @@ LL | Either::One(mut _t) | data moved here | move occurs because `_t` has type `X`, which does not implement the `Copy` trait | +help: `Fn` and `FnMut` closures require captured values to be able to be consumed multiple times, but an `FnOnce` consume them only once + --> $DIR/move-into-closure.rs:25:21 + | +LL | fn consume_fnmut<F: FnMut()>(_f: F) { } + | ^^^^^^^ help: consider borrowing here | LL | match &em { | + error[E0507]: cannot move out of `em.0`, as `em` is a captured variable in an `FnMut` closure - --> $DIR/move-into-closure.rs:123:15 + --> $DIR/move-into-closure.rs:144:15 | LL | let mut em = Either::One(X(Y)); | ------ captured outer variable @@ -415,13 +510,18 @@ LL | Either::One(mut _t) => (), | data moved here | move occurs because `_t` has type `X`, which does not implement the `Copy` trait | +help: `Fn` and `FnMut` closures require captured values to be able to be consumed multiple times, but an `FnOnce` consume them only once + --> $DIR/move-into-closure.rs:25:21 + | +LL | fn consume_fnmut<F: FnMut()>(_f: F) { } + | ^^^^^^^ help: consider borrowing here | LL | match &em { | + error[E0507]: cannot move out of `em.0`, as `em` is a captured variable in an `FnMut` closure - --> $DIR/move-into-closure.rs:130:15 + --> $DIR/move-into-closure.rs:151:15 | LL | let mut em = Either::One(X(Y)); | ------ captured outer variable @@ -438,6 +538,11 @@ LL | Either::One(mut _t) => (), | data moved here | move occurs because `_t` has type `X`, which does not implement the `Copy` trait | +help: `Fn` and `FnMut` closures require captured values to be able to be consumed multiple times, but an `FnOnce` consume them only once + --> $DIR/move-into-closure.rs:25:21 + | +LL | fn consume_fnmut<F: FnMut()>(_f: F) { } + | ^^^^^^^ help: consider borrowing here | LL | match &em { diff --git a/tests/ui/suggestions/option-content-move2.stderr b/tests/ui/suggestions/option-content-move2.stderr index c73e874b403..c8aa6667b58 100644 --- a/tests/ui/suggestions/option-content-move2.stderr +++ b/tests/ui/suggestions/option-content-move2.stderr @@ -14,6 +14,11 @@ LL | LL | var = Some(NotCopyable); | --- variable moved due to use in closure | +help: `Fn` and `FnMut` closures require captured values to be able to be consumed multiple times, but an `FnOnce` consume them only once + --> $DIR/option-content-move2.rs:5:12 + | +LL | fn func<F: FnMut() -> H, H: FnMut()>(_: F) {} + | ^^^^^^^^^^^^ note: if `NotCopyable` implemented `Clone`, you could clone the value --> $DIR/option-content-move2.rs:1:1 | @@ -38,6 +43,12 @@ LL | move || { LL | LL | var = Some(NotCopyableButCloneable); | --- variable moved due to use in closure + | +help: `Fn` and `FnMut` closures require captured values to be able to be consumed multiple times, but an `FnOnce` consume them only once + --> $DIR/option-content-move2.rs:5:12 + | +LL | fn func<F: FnMut() -> H, H: FnMut()>(_: F) {} + | ^^^^^^^^^^^^ error: aborting due to 2 previous errors diff --git a/tests/ui/suggestions/option-content-move3.stderr b/tests/ui/suggestions/option-content-move3.stderr index 68c52352a65..2c9a86c036b 100644 --- a/tests/ui/suggestions/option-content-move3.stderr +++ b/tests/ui/suggestions/option-content-move3.stderr @@ -9,6 +9,7 @@ LL | move || { LL | let x = var; | ^^^ move occurs because `var` has type `NotCopyable`, which does not implement the `Copy` trait | + = help: `Fn` and `FnMut` closures require captured values to be able to be consumed multiple times, but an `FnOnce` consume them only once note: if `NotCopyable` implemented `Clone`, you could clone the value --> $DIR/option-content-move3.rs:2:1 | @@ -37,6 +38,11 @@ LL | move || { LL | let x = var; | --- variable moved due to use in closure | +help: `Fn` and `FnMut` closures require captured values to be able to be consumed multiple times, but an `FnOnce` consume them only once + --> $DIR/option-content-move3.rs:6:12 + | +LL | fn func<F: FnMut() -> H, H: FnMut()>(_: F) {} + | ^^^^^^^^^^^^ note: if `NotCopyable` implemented `Clone`, you could clone the value --> $DIR/option-content-move3.rs:2:1 | @@ -57,6 +63,7 @@ LL | move || { LL | let x = var; | ^^^ move occurs because `var` has type `NotCopyableButCloneable`, which does not implement the `Copy` trait | + = help: `Fn` and `FnMut` closures require captured values to be able to be consumed multiple times, but an `FnOnce` consume them only once help: consider borrowing here | LL | let x = &var; @@ -77,6 +84,11 @@ LL | move || { LL | let x = var; | --- variable moved due to use in closure | +help: `Fn` and `FnMut` closures require captured values to be able to be consumed multiple times, but an `FnOnce` consume them only once + --> $DIR/option-content-move3.rs:6:12 + | +LL | fn func<F: FnMut() -> H, H: FnMut()>(_: F) {} + | ^^^^^^^^^^^^ help: consider cloning the value before moving it into the closure | LL ~ { |
