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077fc26f0a
Uplift `clippy::{drop,forget}_{ref,copy}` lints
This PR aims at uplifting the `clippy::drop_ref`, `clippy::drop_copy`, `clippy::forget_ref` and `clippy::forget_copy` lints.
Those lints are/were declared in the correctness category of clippy because they lint on useless and most probably is not what the developer wanted.
## `drop_ref` and `forget_ref`
The `drop_ref` and `forget_ref` lint checks for calls to `std::mem::drop` or `std::mem::forget` with a reference instead of an owned value.
### Example
```rust
let mut lock_guard = mutex.lock();
std::mem::drop(&lock_guard) // Should have been drop(lock_guard), mutex
// still locked
operation_that_requires_mutex_to_be_unlocked();
```
### Explanation
Calling `drop` or `forget` on a reference will only drop the reference itself, which is a no-op. It will not call the `drop` or `forget` method on the underlying referenced value, which is likely what was intended.
## `drop_copy` and `forget_copy`
The `drop_copy` and `forget_copy` lint checks for calls to `std::mem::forget` or `std::mem::drop` with a value that derives the Copy trait.
### Example
```rust
let x: i32 = 42; // i32 implements Copy
std::mem::forget(x) // A copy of x is passed to the function, leaving the
// original unaffected
```
### Explanation
Calling `std::mem::forget` [does nothing for types that implement Copy](https://doc.rust-lang.org/std/mem/fn.drop.html) since the value will be copied and moved into the function on invocation.
-----
Followed the instructions for uplift a clippy describe here: https://github.com/rust-lang/rust/pull/99696#pullrequestreview-1134072751
cc `@m-ou-se` (as T-libs-api leader because the uplifting was discussed in a recent meeting)
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|---|---|---|
| .. | ||
| auxiliary | ||
| drop_order.rs | ||
| drop-foreign-fundamental.rs | ||
| drop-foreign-fundamental.stderr | ||
| drop-if-let-binding.rs | ||
| drop-on-empty-block-exit.rs | ||
| drop-on-ret.rs | ||
| drop-struct-as-object.rs | ||
| drop-trait-enum.rs | ||
| drop-trait-generic.rs | ||
| drop-trait.rs | ||
| drop-uninhabited-enum.rs | ||
| drop-with-type-ascription-1.rs | ||
| drop-with-type-ascription-2.rs | ||
| dropck_legal_cycles.rs | ||
| dropck-eyepatch-extern-crate.rs | ||
| dropck-eyepatch-reorder.rs | ||
| dropck-eyepatch.rs | ||
| dynamic-drop-async.rs | ||
| dynamic-drop.rs | ||
| issue-979.rs | ||
| issue-2734.rs | ||
| issue-2735-2.rs | ||
| issue-2735-3.rs | ||
| issue-2735.rs | ||
| issue-10028.rs | ||
| issue-17718-const-destructors.rs | ||
| issue-21486.rs | ||
| issue-23338-ensure-param-drop-order.rs | ||
| issue-30018-nopanic.rs | ||
| issue-35546.rs | ||
| issue-48962.rs | ||
| issue-90752-raw-ptr-shenanigans.rs | ||
| issue-90752.rs | ||
| issue-100276.rs | ||
| issue-103107.rs | ||
| no-drop-flag-size.rs | ||
| nondrop-cycle.rs | ||
| repeat-drop-2.rs | ||
| repeat-drop-2.stderr | ||
| repeat-drop.rs | ||
| terminate-in-initializer.rs | ||
| use_inline_dtor.rs | ||