`for (using of =` is incorrectly parsed.

[rbuckton]

🔎 Search Terms

for using of explicit resource management

🕗 Version & Regression Information

• This is the behavior in every version I tried

⏯ Playground Link

https://www.typescriptlang.org/play/?lib=lib.esnext.d.ts&ts=lib.esnext.d.ts#code/GYewTgBAFArgzgSwHYHMImBAvBJMA2+A3EQJQQBGYApgIYDWRQA

💻 Code

for (using of = null;;) break;

🙁 Actual behavior

Reports multiple errors as a result of failed parse, including:

• Expression expected.
• ')' expected.

🙂 Expected behavior

It should parse successfully, much like the following:

for (var of = null;;) break;
for (let of = null;;) break;
for (const of = null;;) break;

Additional information about the issue

This was discussed in the Explicit Resource Management Repo here: tc39/proposal-explicit-resource-management#248

The test262 test for this can be found here: tc39/test262@fc3079a#diff-4ea0f4ef51852a9dec7036a93ec9576c387d2ad22eaf63992e36f81919c75ce3R14