TS1508: Unexpected '?'. Did you mean to escape it with backslash? shouldn't report even with `v` flag

🔎 Search Terms

TS1508, "Did you mean to escape it with backslash?"

🕗 Version & Regression Information

• This changed between versions ______ and _______
• This changed in https://github.com/microsoft/TypeScript/pull/55600 which introduced regular expression syntax checking
• This is the behavior in every version I tried, and I reviewed the FAQ for entries about _________
• I was unable to test this on prior versions because _______

⏯ Playground Link

https://www.typescriptlang.org/play/?target=11#code/PQbQ-AZAusBuBQQ

💻 Code

/[?&]/v

🙁 Actual behavior

The error "TS1508: Unexpected '?'. Did you mean to escape it with backslash?" is given.

🙂 Expected behavior

No error because ? doesn't need to be escaped in a character class even with a v flag.

Additional information about the issue

Other characters like { do need escaping with the v flag, but ? gets no runtime errors, so I don't see why this has to err now.