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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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|---|---|---|
| .. | ||
| assert | ||
| deriving | ||
| format_foreign | ||
| alloc_error_handler.rs | ||
| asm.rs | ||
| assert.rs | ||
| cfg_accessible.rs | ||
| cfg_eval.rs | ||
| cfg.rs | ||
| cmdline_attrs.rs | ||
| compile_error.rs | ||
| concat_bytes.rs | ||
| concat_idents.rs | ||
| concat.rs | ||
| derive.rs | ||
| edition_panic.rs | ||
| env.rs | ||
| errors.rs | ||
| format_foreign.rs | ||
| format.rs | ||
| global_allocator.rs | ||
| lib.rs | ||
| log_syntax.rs | ||
| proc_macro_harness.rs | ||
| source_util.rs | ||
| standard_library_imports.rs | ||
| test_harness.rs | ||
| test.rs | ||
| trace_macros.rs | ||
| type_ascribe.rs | ||
| util.rs | ||