No diagnostics for `cfg`-ed out methods
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A-diagnostics
T-compiler
- Dominant language
- Rust
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Description
Code
compile with --target thumbv6m-none-eabi
or see https://godbolt.org/z/nEjfqMP5v
#![no_std]
use core::sync::atomic::{AtomicBool, Ordering};
fn test(){
AtomicBool::new(false).fetch_not(Ordering::Relaxed);
}
Current output
error[E0599]: no method named `fetch_not` found for struct `AtomicBool` in the current scope
--> <source>:6:28
|
6 | AtomicBool::new(false).fetch_not(Ordering::Relaxed);
| ^^^^^^^^^ method not found in `AtomicBool`
Desired output
Add this:
note: `AtomicBool` has a method named `fetch_not` but it is inactive because its cfg predicate evaluated to false
Rationale and extra context
https://github.com/rust-lang/rust/pull/109005/ added very helpful diagnostics for a similar case
Other cases
No response
Rust Version
rustc 1.81.0 (eeb90cda1 2024-09-04)
binary: rustc
commit-hash: eeb90cda1969383f56a2637cbd3037bdf598841c
commit-date: 2024-09-04
host: x86_64-unknown-linux-gnu
release: 1.81.0
LLVM version: 18.1.7
Compiler returned: 0
Anything else?
No response
Contributor guide
First steps
- Read the whole issue, then the project's contributing guide.
- Comment on the issue to say you are picking it up — it saves two people doing the same work.
- Fork the repository and make your change on a branch.
- Open a pull request that references the issue number.
Research direction
Reproduce the diagnostic with rustc --target thumbv6m-none-eabi using the AtomicBool example, then study the similar diagnostics added by rust-lang/rust#109005. Trace the method-not-found diagnostic path and make the completed output include the requested note when a cfg predicate disables the method; verify it with a regression test for this example.
Written by the indexing model from the issue text.
Assessment
- Tech stack
- rust
- Domain
- compilers
- Issue type
- Bug
- Difficulty
- 4/5
- Estimated time
- 3-5 days
- Activity status
- Stale
- Clarity
- Mostly clear
- Newbie friendliness
- 45/100