[Bug]: AST changed in v7.18.9

[fisker]

💻

• Would you like to work on a fix?

How are you using Babel?

Programmatic API (babel.transform, babel.parse)

Input code

new A < B >
C

Configuration file name

No response

Configuration

No response

Current and expected behavior

Not sure when it changed, but after 7.18.5, I'm not familiar with this syntax, not sure what's correct. But Prettier format it different than typescript parser.

// `typescript` parser and older babel
new A() < B > C;

// new 
new A<B>();
C;

I think B is a type parameter now.

Same as @typescript-eslint/eslint-plugin parser?

Environment

N/A

Possible solution

No response

Additional context

Prettier PR prettier/prettier#13065

[babel-bot]

Hey @fisker! We really appreciate you taking the time to report an issue. The collaborators on this project attempt to help as many people as possible, but we're a limited number of volunteers, so it's possible this won't be addressed swiftly.

If you need any help, or just have general Babel or JavaScript questions, we have a vibrant Slack community that typically always has someone willing to help. You can sign-up here for an invite.

[JLHwung]

The new behaviour is intended: microsoft/TypeScript#49353, Babel aligns to the new behaviour in #14636.

See also the TS playground with TS nightly.

I think we can also add tests/format/typescript to our prettier-e2e tests.

[fisker]

Thank you!

[fisker]

I think we can also add tests/format/typescript

tests/format/flow tests/format/flow-repo too?