rust/tests/ui/derives/deriving-with-repr-packed.stderr
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

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warning: byte slice in a packed struct that derives a built-in trait
--> $DIR/deriving-with-repr-packed.rs:31:5
|
LL | #[derive(Debug)]
| ----- in this derive macro expansion
...
LL | data: [u8],
| ^^^^^^^^^^
|
= warning: this was previously accepted by the compiler but is being phased out; it will become a hard error in a future release!
= note: for more information, see issue #107457 <https://github.com/rust-lang/rust/issues/107457>
= help: consider implementing the trait by hand, or remove the `packed` attribute
= note: `#[warn(byte_slice_in_packed_struct_with_derive)]` on by default
= note: this warning originates in the derive macro `Debug` (in Nightly builds, run with -Z macro-backtrace for more info)
warning: string slice in a packed struct that derives a built-in trait
--> $DIR/deriving-with-repr-packed.rs:41:5
|
LL | #[derive(Debug)]
| ----- in this derive macro expansion
...
LL | data: str,
| ^^^^^^^^^
|
= warning: this was previously accepted by the compiler but is being phased out; it will become a hard error in a future release!
= note: for more information, see issue #107457 <https://github.com/rust-lang/rust/issues/107457>
= help: consider implementing the trait by hand, or remove the `packed` attribute
= note: this warning originates in the derive macro `Debug` (in Nightly builds, run with -Z macro-backtrace for more info)
error[E0507]: cannot move out of `self` which is behind a shared reference
--> $DIR/deriving-with-repr-packed.rs:22:10
|
LL | #[derive(Debug, Default)]
| ----- in this derive macro expansion
LL | #[repr(packed)]
LL | struct X(Y);
| ^ move occurs because `self.0` has type `Y`, which does not implement the `Copy` trait
|
note: if `Y` implemented `Clone`, you could clone the value
--> $DIR/deriving-with-repr-packed.rs:16:1
|
LL | struct Y(usize);
| ^^^^^^^^ consider implementing `Clone` for this type
...
LL | struct X(Y);
| - you could clone this value
= note: `#[derive(Debug)]` triggers a move because taking references to the fields of a packed struct is undefined behaviour
= note: this error originates in the derive macro `Debug` (in Nightly builds, run with -Z macro-backtrace for more info)
error: aborting due to 1 previous error; 2 warnings emitted
For more information about this error, try `rustc --explain E0507`.
Future incompatibility report: Future breakage diagnostic:
warning: byte slice in a packed struct that derives a built-in trait
--> $DIR/deriving-with-repr-packed.rs:31:5
|
LL | #[derive(Debug)]
| ----- in this derive macro expansion
...
LL | data: [u8],
| ^^^^^^^^^^
|
= warning: this was previously accepted by the compiler but is being phased out; it will become a hard error in a future release!
= note: for more information, see issue #107457 <https://github.com/rust-lang/rust/issues/107457>
= help: consider implementing the trait by hand, or remove the `packed` attribute
= note: `#[warn(byte_slice_in_packed_struct_with_derive)]` on by default
= note: this warning originates in the derive macro `Debug` (in Nightly builds, run with -Z macro-backtrace for more info)
Future breakage diagnostic:
warning: string slice in a packed struct that derives a built-in trait
--> $DIR/deriving-with-repr-packed.rs:41:5
|
LL | #[derive(Debug)]
| ----- in this derive macro expansion
...
LL | data: str,
| ^^^^^^^^^
|
= warning: this was previously accepted by the compiler but is being phased out; it will become a hard error in a future release!
= note: for more information, see issue #107457 <https://github.com/rust-lang/rust/issues/107457>
= help: consider implementing the trait by hand, or remove the `packed` attribute
= note: `#[warn(byte_slice_in_packed_struct_with_derive)]` on by default
= note: this warning originates in the derive macro `Debug` (in Nightly builds, run with -Z macro-backtrace for more info)