Point at the string inside literal and mention if we need string inte…

[lyming2007]

…rpolation

modified:   compiler/rustc_passes/src/liveness.rs

[rust-highfive]

Thanks for the pull request, and welcome! The Rust team is excited to review your changes, and you should hear from @oli-obk (or someone else) soon.

Please see the contribution instructions for more information.

[TaKO8Ki]

Could you add a ui test about this suggestion?
https://rustc-dev-guide.rust-lang.org/tests/ui.html

[lyming2007]

Could you add a ui test about this suggestion? https://rustc-dev-guide.rust-lang.org/tests/ui.html
Given this test case:

cat main.rs
fn foo(xyza: &str) {
    let _ = "{xyza}";
}


fn main() {
  foo("aaa");
}

The problem for this specific issue is we're improving the warning for unused variables. But the ui test script won't emit the unused variables with the command -A unused. Here is the full command line of the testing script:

/home/lym/rust3/rust/build/x86_64-unknown-linux-gnu/stage1/bin/rustc /home/lym/rust3/rust/src/test/ui/type/issue-100584.rs -Zthreads=1 --target=x86_64-unknown-linux-gnu --error-format json --json future-incompat -Ccodegen-units=1 -Zui-testing -Zdeduplicate-diagnostics=no -Cstrip=debuginfo --emit metadata -C prefer-dynamic --out-dir /home/lym/rust3/rust/build/x86_64-unknown-linux-gnu/test/ui/type/issue-100584 -A unused -Crpath -Cdebuginfo=0 -Lnative=/home/lym/rust3/rust/build/x86_64-unknown-linux-gnu/native/rust-test-helpers -L /home/lym/rust3/rust/build/x86_64-unknown-linux-gnu/test/ui/type/issue-100584/auxiliary

Thus, the output of this case is nothing and always failed.
Could you give me more suggestions on this situation?

[oli-obk]

You can try adding #![deny(unused)] to the file

[lyming2007]

yes that works. thanks

[oli-obk]

@bors r+

Thanks! and sorry for the let/else confusion

[bors]

📌 Commit 39ffabb has been approved by oli-obk

It is now in the queue for this repository.

[lyming2007]

@bors r+

Thanks! and sorry for the let/else confusion

No worries. Thank you for all useful suggestions, especially for beginners like me. I've learned a lot from this back-and-forth work with you. Appreciate it!