Bug Report

🔎 Search Terms

asi new expression type arguments

🕗 Version & Regression Information

TypeScript 4.7 Nightly (tested with the playground). This syntax has never been valid before TS 4.7.

new X<T>; is valid syntax since #47607 (cc @ahejlsberg)

⏯ Playground Link

Playground link with relevant code

💻 Code

class A<T> {}

new A<number>

if (0) {}

🙁 Actual behavior

It's parsed as if it was

class A<T> {}

new A<number> if (0) {}

thus it reports a few errors (number is used in a value position, and if is a reserved word).

🙂 Expected behavior

I would expect ASI to kick in, and to parse the code as if it was

class A<T> {}

new A<number>;

if (0) {}

Context

I'm implementing this in Babel. If it's expected that ASI does not work here, what are the rules to differentiate between a new expression with only type arguments, and a relational comparison?