Unexpected ASI after `declare` (regression since version 4.4)

[evanw]

Bug Report

🔎 Search Terms

declare asi semicolon

🕗 Version & Regression Information

• This changed between version 4.3.5 (where it doesn't happen) and version 4.4.4 (where it starts happening)

⏯ Playground Link

Playground link for version 4.3.5 (fine)
Playground link for version 4.4.4 (problematic)

💻 Code

Some random examples that TS 5.1 considers valid syntax (not exhaustive):

declare let declare: any, foo: any
declare foo

declare let declare: any, foo: any
declare foo()

declare let declare: any, foo: any
declare {foo}

🙁 Actual behavior

TypeScript silently does automatic semicolon insertion after declare in all of these cases without generating any syntax errors.

🙂 Expected behavior

I expected these to be syntax errors. I did not expect TypeScript to silently be doing automatic semicolon insertion after declare here as if this is valid syntax.

[jakebailey]

FWIW this (and #54760) bisects to #43005.