Constructor return type annotations produce invalid JS syntax

[rtsao]

Source:

class Foo {
  constructor(): Foo {
    return this;
  }
}

Transformed (actual):

class Foo {
  constructor():  {
    return this;
  }
}

Transformed (expected):

class Foo {
  constructor()  {
    return this;
  }
}

Reproductions:

• TS: https://sucrase.io/#transforms=typescript&code=class%20Foo%20%7B%0A%20%20constructor()%3A%20Foo%20%7B%0A%20%20%20%20return%20this%3B%0A%20%20%7D%0A%7D
• Flow: https://sucrase.io/#transforms=flow&code=class%20Foo%20%7B%0A%20%20constructor()%3A%20Foo%20%7B%0A%20%20%20%20return%20this%3B%0A%20%20%7D%0A%7D

[alangpierce]

Hi @rtsao , sorry for the delay, and thanks for reporting! That syntax is actually invalid in both TypeScript and Flow, so I'd normally call it out of scope for Sucrase, but I understand the error is pretty confusing, and it's easy to fix in Sucrase, so I'll put up a PR to fix.