Parsing error when using @babel/plugin-proposal-decorators

[millsp]

Bug Report

Current Behavior
Babel parser gets confused when using decorators.

Additional context/Screenshots

    Module parse failed: Can not use keyword 'await' outside an async function (86:8)
    You may need an appropriate loader to handle this file type.
    |       key: "t",
    |       value: function value() {
    >         await this.s();
    |       }
    |     }, {
     @ ./src/index.js 7:13-40

As you can see await this.s() is within an async so there should be no problem.
Remove the decorator then the problem is gone immediately.

Input Code

function decorator(Class) {
     return function (...args) {
          return new Class(...args);
     }
}

@decorator
class Test {
     constructor(props) {
     }

     async t() {
          await this.s()
     }

     async s() {
     }
}

new Test();

Expected behavior/code
This is supposed to compile just fine.

Babel Configuration (.babelrc, package.json, cli command)

module.exports = function (api) {
     //console.log('----------------------------test-------------------------');
     api.cache(true);

     const presets = [
          ['@babel/preset-env'],
     ];

     const plugins = [
          ['@babel/plugin-transform-runtime'],
          ['@babel/plugin-proposal-decorators', {decoratorsBeforeExport: false}],
          ['@babel/plugin-proposal-class-properties'],
     ];

     return {
          presets: presets,
          plugins: plugins,
     };

};

Environment

• Babel version(s): 7.1.0
• Node/npm version: [Node 8.12 / NPM 6.4.1]
• OS: [Ubuntu 16.04 LTS]
• How you are using Babel: ['cli', 'webpack']

[babel-bot]

Hey @pirix-gh! 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.

[nicolo-ribaudo]

Duplicated of #8737, fixed by #8742