Legacy Decorators + Generator Methods

[buschtoens]

Bug Report

Current Behavior
Legacy decorators cannot decorate generator methods. An Unexpected token error is thrown:

/repl: Unexpected token (5:21)

  3 | class Foo {
  4 |   @deco
> 5 |   *generatorMethod() {}
    |                      ^
  6 | }

Input Code
REPL

function deco() {}

class Foo {
  @deco
  *generatorMethod() {}
}

Expected behavior/code
No error should be thrown and the method should be transpiled like normal methods.

Babel Configuration
Presets: es2015 + stage-2
Decorators: legacy

Environment
Babel version(s): 7.4.3

Possible Solution
#8742

Additional context/Screenshots
#5704, babel/babylon#382

[babel-bot]

Hey @buschtoens! 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
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[nicolo-ribaudo]

We should update our parser to wycats/javascript-decorators@e240cbc, so that we also match TS's behavior.

[buschtoens]

I never meddled with the Babel parser, but I would like to help implement this. Can you provide some pointers?

[robclancy]

I don't understand how stage 1 decorators can be recommended over stage 2 while this bug exists. It's a now default JS feature that isn't compatible but was fixed in stage 2.