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Missing parenthesis in static_mut_refs diagnostic suggestion #131977

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CharlyCst opened this issue Oct 20, 2024 · 1 comment
Open

Missing parenthesis in static_mut_refs diagnostic suggestion #131977

CharlyCst opened this issue Oct 20, 2024 · 1 comment
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A-diagnostics Area: Messages for errors, warnings, and lints A-suggestion-diagnostics Area: Suggestions generated by the compiler applied by `cargo fix` D-invalid-suggestion Diagnostics: A structured suggestion resulting in incorrect code. E-easy Call for participation: Easy difficulty. Experience needed to fix: Not much. Good first issue. T-compiler Relevant to the compiler team, which will review and decide on the PR/issue.

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@CharlyCst
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CharlyCst commented Oct 20, 2024

Code

static mut TEST: usize = 0;

fn main() {
    let _ = unsafe { (&TEST) as *const usize };
}

Current output

   Compiling playground v0.0.1 (/playground)
warning: creating a shared reference to mutable static is discouraged
 --> src/main.rs:4:22
  |
4 |     let _ = unsafe { (&TEST) as *const usize };
  |                      ^^^^^^^ shared reference to mutable static
  |
  = note: for more information, see <https://doc.rust-lang.org/nightly/edition-guide/rust-2024/static-mut-references.html>
  = note: shared references to mutable statics are dangerous; it's undefined behavior if the static is mutated or if a mutable reference is created for it while the shared reference lives
  = note: `#[warn(static_mut_refs)]` on by default
help: use `&raw const` instead to create a raw pointer
  |
4 |     let _ = unsafe { &raw const TEST) as *const usize };
  |                      ~~~~~~~~~~

warning: `playground` (bin "playground") generated 1 warning
    Finished `dev` profile [unoptimized + debuginfo] target(s) in 0.73s
     Running `target/debug/playground`

Desired output

   Compiling playground v0.0.1 (/playground)
warning: creating a shared reference to mutable static is discouraged
 --> src/main.rs:4:22
  |
4 |     let _ = unsafe { (&TEST) as *const usize };
  |                      ^^^^^^^ shared reference to mutable static
  |
  = note: for more information, see <https://doc.rust-lang.org/nightly/edition-guide/rust-2024/static-mut-references.html>
  = note: shared references to mutable statics are dangerous; it's undefined behavior if the static is mutated or if a mutable reference is created for it while the shared reference lives
  = note: `#[warn(static_mut_refs)]` on by default
help: use `&raw const` instead to create a raw pointer
  |
4 |     let _ = unsafe { (&raw const TEST) as *const usize };
  |                       ~~~~~~~~~~

warning: `playground` (bin "playground") generated 1 warning
    Finished `dev` profile [unoptimized + debuginfo] target(s) in 0.73s
     Running `target/debug/playground`

Rationale and extra context

The suggestion removes the left parenthesis, but keeps the right parenthesis. Of course the proposed change does not compile.
Original code: (&TEST) suggestion: &raw const TEST)

Other cases

No response

Rust Version

rustc 1.84.0-nightly (da93539 2024-10-19)
binary: rustc
commit-hash: da93539
commit-date: 2024-10-19
host: aarch64-apple-darwin
release: 1.84.0-nightly
LLVM version: 19.1.1

Anything else?

Link to rust playground

@CharlyCst CharlyCst added A-diagnostics Area: Messages for errors, warnings, and lints T-compiler Relevant to the compiler team, which will review and decide on the PR/issue. labels Oct 20, 2024
@jieyouxu jieyouxu added A-suggestion-diagnostics Area: Suggestions generated by the compiler applied by `cargo fix` D-invalid-suggestion Diagnostics: A structured suggestion resulting in incorrect code. E-easy Call for participation: Easy difficulty. Experience needed to fix: Not much. Good first issue. labels Oct 21, 2024
@indegrowl
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Pretty straightforward! I'll work on it. It'll be my first PR.

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Labels
A-diagnostics Area: Messages for errors, warnings, and lints A-suggestion-diagnostics Area: Suggestions generated by the compiler applied by `cargo fix` D-invalid-suggestion Diagnostics: A structured suggestion resulting in incorrect code. E-easy Call for participation: Easy difficulty. Experience needed to fix: Not much. Good first issue. T-compiler Relevant to the compiler team, which will review and decide on the PR/issue.
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