Small code makes parser hang

[Y--]

Hi!

If you try to paste this small snipped in the AS editor, and try to look at the WASM generated, the page becomes unresponsive:

export function foo() {
  if (idof<Foo>() == idof<Bar>) {
    baz();
  } else {
    `Some string`
  }
}

Note that:

• the code is not correct (it is missing the parenthesis to call idof in idof<Bar>)
• if you remove the string template, from the else branch, the issue disappear
• if you fix the idof call, the issue disappear

Let me know if you need any additional detail on this.

Thanks!

[dcodeIO]

Looks like an endless loop not properly skipping over the missing parenthesis (or subsequent code in error recovery). Thanks for your report!

[yjhmelody]

@dcodeIO I also encountered endless loop before, but it was a more borderline situation, see #1801

[HerrCai0907]

@dcodeIO I also encountered endless loop before, but it was a more borderline situation, see #1801

They are same issue. After parser error, template string will cause infinite loop. But It's a question why parser error....

class Foo<CB = (data: u32) => void> {                           => Error: TS1003: Identifier expected
    private foo(): void {
        throw new Error(``);
    }
}

but the below is correct

type T = (data: u32) => void;
class Foo<CB = T> { 
    private foo(): void {
        throw new Error(``);
    }
}