noUnusedLocals incorrectly reports `using` resources as unused unless explicitly used

[dj-foxxy]

🔎 Search Terms

noUnusedLocals
using

🕗 Version & Regression Information

Present on all releases supporting using

⏯ Playground Link

https://www.typescriptlang.org/play/?noUnusedLocals=true&target=99&ts=5.9.0-dev.20250618#code/N4KABBYK4M4JYDsDmYBmB7dYC8ZhgG0BlATwFsAjdAGwDoATOGAB3RgFMBdACgEo8AvmAEBuEAKA

💻 Code

{
    using foo = { [Symbol.dispose]() {} };
}

🙁 Actual behavior

foo is flagged as unused by noUnusedLocals

🙂 Expected behavior

foo is not flagged by noUnusedLocals because it's implicitly used at the end of the scope when its [Symbol.dispose] property is called.

Additional information about the issue

Not explicitly referencing resources is common (e.g., mutexs) so this feels like a bug.

[MartinJohns]

Duplicate of #55538. Used search terms: using unused in:title

Just prefix your variable with _ making it clear that this intentional.