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7d7004d3e6
Clarify `invalid_reference_casting` lint around interior mutable types
This is PR intends to clarify the `invalid_reference_casting` lint around interior mutable types by adding a note for them saying that they should go through `UnsafeCell::get`.
So for this code:
```rust
let cell = &std::cell::UnsafeCell::new(0);
let _num = &mut *(cell as *const _ as *mut i32);
```
the following note will be added to the lint output:
```diff
error: casting `&T` to `&mut T` is undefined behavior, even if the reference is unused, consider instead using an `UnsafeCell`
--> $DIR/reference_casting.rs:68:16
|
LL | let _num = &mut *(cell as *const _ as *mut i32);
| ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
|
= note: for more information, visit <https://doc.rust-lang.org/book/ch15-05-interior-mutability.html>
+ = note: even for types with interior mutability, the only legal way to obtain a mutable pointer from a shared reference is through `UnsafeCell::get`
```
Suggestion are welcome around the note contents.
Fixes https://github.com/rust-lang/rust/issues/116410
cc `@RalfJung`
|
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|---|---|---|
| .. | ||
| nonstandard_style | ||
| array_into_iter.rs | ||
| async_fn_in_trait.rs | ||
| builtin.rs | ||
| context.rs | ||
| deref_into_dyn_supertrait.rs | ||
| drop_forget_useless.rs | ||
| early.rs | ||
| enum_intrinsics_non_enums.rs | ||
| errors.rs | ||
| expect.rs | ||
| for_loops_over_fallibles.rs | ||
| foreign_modules.rs | ||
| hidden_unicode_codepoints.rs | ||
| internal.rs | ||
| invalid_from_utf8.rs | ||
| late.rs | ||
| let_underscore.rs | ||
| levels.rs | ||
| lib.rs | ||
| lints.rs | ||
| map_unit_fn.rs | ||
| methods.rs | ||
| multiple_supertrait_upcastable.rs | ||
| non_ascii_idents.rs | ||
| non_fmt_panic.rs | ||
| nonstandard_style.rs | ||
| noop_method_call.rs | ||
| opaque_hidden_inferred_bound.rs | ||
| pass_by_value.rs | ||
| passes.rs | ||
| ptr_nulls.rs | ||
| redundant_semicolon.rs | ||
| reference_casting.rs | ||
| tests.rs | ||
| traits.rs | ||
| types.rs | ||
| unused.rs | ||