rust/tests/ui/moves/use_of_moved_value_copy_suggestions.rs
Esteban Küber d68f2a6b71 Mention when type parameter could be Clone
```
error[E0382]: use of moved value: `t`
  --> $DIR/use_of_moved_value_copy_suggestions.rs:7:9
   |
LL | fn duplicate_t<T>(t: T) -> (T, T) {
   |                   - move occurs because `t` has type `T`, which does not implement the `Copy` trait
...
LL |     (t, t)
   |      -  ^ value used here after move
   |      |
   |      value moved here
   |
help: if `T` implemented `Clone`, you could clone the value
  --> $DIR/use_of_moved_value_copy_suggestions.rs:4:16
   |
LL | fn duplicate_t<T>(t: T) -> (T, T) {
   |                ^ consider constraining this type parameter with `Clone`
...
LL |     (t, t)
   |      - you could clone this value
help: consider restricting type parameter `T`
   |
LL | fn duplicate_t<T: Copy>(t: T) -> (T, T) {
   |                 ++++++
```

The `help` is new. On ADTs, we also extend the output with span labels:

```
error[E0507]: cannot move out of static item `FOO`
  --> $DIR/issue-17718-static-move.rs:6:14
   |
LL |     let _a = FOO;
   |              ^^^ move occurs because `FOO` has type `Foo`, which does not implement the `Copy` trait
   |
note: if `Foo` implemented `Clone`, you could clone the value
  --> $DIR/issue-17718-static-move.rs:1:1
   |
LL | struct Foo;
   | ^^^^^^^^^^ consider implementing `Clone` for this type
...
LL |     let _a = FOO;
   |              --- you could clone this value
help: consider borrowing here
   |
LL |     let _a = &FOO;
   |              +
```
2024-04-24 22:21:15 +00:00

89 lines
2.1 KiB
Rust

//@ run-rustfix
#![allow(dead_code)]
fn duplicate_t<T>(t: T) -> (T, T) {
//~^ HELP consider restricting type parameter `T`
//~| HELP if `T` implemented `Clone`, you could clone the value
(t, t) //~ use of moved value: `t`
}
fn duplicate_opt<T>(t: Option<T>) -> (Option<T>, Option<T>) {
//~^ HELP consider restricting type parameter `T`
(t, t) //~ use of moved value: `t`
}
fn duplicate_tup1<T>(t: (T,)) -> ((T,), (T,)) {
//~^ HELP consider restricting type parameter `T`
(t, t) //~ use of moved value: `t`
}
fn duplicate_tup2<A, B>(t: (A, B)) -> ((A, B), (A, B)) {
//~^ HELP consider restricting type parameters
(t, t) //~ use of moved value: `t`
}
fn duplicate_custom<T>(t: S<T>) -> (S<T>, S<T>) {
//~^ HELP consider restricting type parameter `T`
(t, t) //~ use of moved value: `t`
}
struct S<T>(T);
trait Trait {}
impl<T: Trait + Clone> Clone for S<T> {
fn clone(&self) -> Self {
Self(self.0.clone())
}
}
impl<T: Trait + Copy> Copy for S<T> {}
trait A {}
trait B {}
// Test where bounds are added with different bound placements
fn duplicate_custom_1<T>(t: S<T>) -> (S<T>, S<T>) where {
//~^ HELP consider restricting type parameter `T`
(t, t) //~ use of moved value: `t`
}
fn duplicate_custom_2<T>(t: S<T>) -> (S<T>, S<T>)
where
T: A,
//~^ HELP consider further restricting this bound
{
(t, t) //~ use of moved value: `t`
}
fn duplicate_custom_3<T>(t: S<T>) -> (S<T>, S<T>)
where
T: A,
//~^ HELP consider further restricting this bound
T: B,
{
(t, t) //~ use of moved value: `t`
}
fn duplicate_custom_4<T: A>(t: S<T>) -> (S<T>, S<T>)
//~^ HELP consider further restricting this bound
where
T: B,
{
(t, t) //~ use of moved value: `t`
}
#[rustfmt::skip]
fn existing_colon<T:>(t: T) {
//~^ HELP consider restricting type parameter `T`
//~| HELP if `T` implemented `Clone`, you could clone the value
[t, t]; //~ use of moved value: `t`
}
fn existing_colon_in_where<T>(t: T) //~ HELP if `T` implemented `Clone`, you could clone the value
where
T:,
//~^ HELP consider further restricting type parameter `T`
{
[t, t]; //~ use of moved value: `t`
}
fn main() {}