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Unused variables inside if-let guards don't get detected #119383

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fmease opened this issue Dec 28, 2023 · 0 comments · Fixed by #119402
Closed

Unused variables inside if-let guards don't get detected #119383

fmease opened this issue Dec 28, 2023 · 0 comments · Fixed by #119402
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A-lints Area: Lints (warnings about flaws in source code) such as unused_mut. C-bug Category: This is a bug. F-if_let_guard `#![feature(if_let_guard)]` T-compiler Relevant to the compiler team, which will review and decide on the PR/issue.

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fmease commented Dec 28, 2023

I expected the following code to fail to compile due to the unused variable unused but it actually compiled successfully:

#![feature(if_let_guard)]
#![deny(unused_variables)]

fn main() {
    match () {
        () if let Some(unused) = Some(()) => {}
        _ => {}
    }
}
@fmease fmease added A-lints Area: Lints (warnings about flaws in source code) such as unused_mut. T-compiler Relevant to the compiler team, which will review and decide on the PR/issue. C-bug Category: This is a bug. F-if_let_guard `#![feature(if_let_guard)]` labels Dec 28, 2023
@rustbot rustbot added the needs-triage This issue may need triage. Remove it if it has been sufficiently triaged. label Dec 28, 2023
@fmease fmease removed the needs-triage This issue may need triage. Remove it if it has been sufficiently triaged. label Dec 28, 2023
@est31 est31 mentioned this issue Dec 29, 2023
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matthiaskrgr added a commit to matthiaskrgr/rust that referenced this issue Dec 29, 2023
@matthiaskrgr
Rollup merge of rust-lang#119402 - est31:fix_if_guard_unused, r=compi…
efd9fd6 
…ler-errors

Also walk bindings created by if-let guards

This change makes the `unused_variables` lint pick up unused bindings created by if-let guards.

Fixes rust-lang#119383
rust-timer added a commit to rust-lang-ci/rust that referenced this issue Dec 29, 2023
@rust-timer
Unrolled build for rust-lang#119402
da86291 
Rollup merge of rust-lang#119402 - est31:fix_if_guard_unused, r=compiler-errors

Also walk bindings created by if-let guards

This change makes the `unused_variables` lint pick up unused bindings created by if-let guards.

Fixes rust-lang#119383
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A-lints Area: Lints (warnings about flaws in source code) such as unused_mut. C-bug Category: This is a bug. F-if_let_guard `#![feature(if_let_guard)]` T-compiler Relevant to the compiler team, which will review and decide on the PR/issue.
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Also walk bindings created by if-let guards est31/rust
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@fmease @rustbot