[Bug] do expression in generator function compiles wrong

[xialvjun]

Bug Report

• I would like to work on a fix!

Current behavior

• REPL

A B is ok, but C is wrong.

Input Code

function* C() {
  let p = yield 'asdasd';
  return m(
    'div',
    m('p', p),
    do {
      let b = yield 123;
      m('button', b)
    },
  );
}

Expected behavior

function* C() {
  let p = yield 'asdasd';
  return m('div', m('p', p), yield* function* () {
    let b = yield 123;
    return m('button', b);
  }());
}

• Babel version(s): [e.g. v7.12.0]
• Node/npm version: [e.g. Node 12/npm 7]
• OS: [e.g. macOS 10.15.4, Windows 10]
• Monorepo: [e.g. yes/no/Lerna]
• How you are using Babel: [e.g. webpack, rollup, parcel, babel-register]

[babel-bot]

Hey @xialvjun! 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."

[bakkot]

Note that the code produced for C isn't even legal: it has a yield expression in a non-generator function. When there's a yield, you have to generate a generator and yield* it. (There's some discussion of this in this issue.)

[JLHwung]

Fixed in #10101