--experimental-scope-hoisting not working with rollup build

[katzIdo]

🐛 bug report

in the following example you can see a problem with --experimental-scope-hoisting when using rollup build cjs

🤔 Expected Behavior

Given a project with lerna and multiple packages

package	build	script
hoistexample-rollup	rollup	rollup src/index.js --file lib/index.js --format cjs
hoistexample-ts	ts	tsc --module commonjs --target es5 --outDir lib

When a main package imports the packages 
And bundle it all with 
 # parcel build -o build index.js  --experimental-scope-hoisting --no-minify 
Then  parcel change the variables name of the rollup build correctly as it does for ts build

😯 Current Behavior

Given a project with lerna and multiple packages

package	build	script
hoistexample-rollup	rollup	rollup src/index.js --file lib/index.js --format cjs
hoistexample-ts	ts	tsc --module commonjs --target es5 --outDir lib

When a main package imports the packages 
And bundle it all with 
 # parcel build -o build index.js  --experimental-scope-hoisting --no-minify 
Then parcel change the variables name of the rollup build incorrectly 
And runtime throw exception of ReferenceError

💁 Possible Solution

you can see from the example
that the problem occurs when doing the export in one line.

export class failurtestHositingRollup2 {
 static create() {
   return new failurtestHositingRollup2();
 }
};

export default class failurtestHositingRollup {
 static create() {
   return new failurtestHositingRollup();
 }
}

💻 Code Sample

parcel bundle with ts import build:

var $sbuw$var$testHositing =
/** @class */
function () {
  function testHositing() {}

  testHositing.create = function () {
    return new testHositing();
  };

  return testHositing;
}();

parcel bundle with rollup import build:

class $gcK$var$failurtestHositingRollup {
  static create() {
    return new failurtestHositingRollup();
  }

}

🌍 Your Environment

Software	Version(s)
parcel-bundler	1.6.1
Node	v10.15.0
Yarn	1.12.3
Operating System	MAC

[devongovett]

I believe this is a bug in Babel's scope tracking. See here for a reduced test case: https://astexplorer.net/#/gist/f1cb0faddd7b06a58e34f59051c78c39/ebab99e1bb5f0be982245db354e9b4abd48c9741.

The console.log in that example outputs 1 reference to Test (the export declaration) when it should output 2 (including the reference in create). If you comment out the call to path.scope.crawl() however, it does output 2 correctly, so something about calling crawl again is messing it up. I tried removing our call to crawl in the scope hoisting code, but that broke other tests. Not sure what's going on there.

[devongovett]

Managed to work around the issue by clearing babel's scope cache before we re-crawl. #2986