Prevent nameclashes with internal variables

src/scope-hoisting/concat.js

@@ -7,7 +7,7 @@ const treeShake = require('./shake');
 const mangleScope = require('./mangler');
 const {getName, getIdentifier} = require('./utils');
 
-const EXPORTS_RE = /^\$(.+?)\$exports$/;
+const EXPORTS_RE = /^\$([^$]+)\$exports$/;
 
 const DEFAULT_INTEROP_TEMPLATE = template(
   'var NAME = $parcel$interopDefault(MODULE)'

src/scope-hoisting/shake.js

@@ -1,6 +1,6 @@
 const t = require('babel-types');
 
-const EXPORTS_RE = /^\$(.+?)\$exports$/;
+const EXPORTS_RE = /^\$([^$]+)\$exports$/;
 
 /**
  * This is a small small implementation of dead code removal specialized to handle

test/integration/scope-hoisting/es6/name-clash/a.js

@@ -0,0 +1,3 @@
+import {foo} from './b'
+
+output = foo()

test/integration/scope-hoisting/es6/name-clash/b.js

@@ -0,0 +1,3 @@
+var $exports = module.exports = {}
+
+$exports.foo = () => 'bar'

test/scope-hoisting.js

@@ -330,6 +330,15 @@ describe('scope hoisting', function() {
       let output = await run(b);
       assert.deepEqual(output, 'bar');
     });
+
+    it('should not nameclash with internal variables', async function() {
+      let b = await bundle(
+        __dirname + '/integration/scope-hoisting/es6/name-clash/a.js'
+      );
+
+      let output = await run(b);
+      assert.deepEqual(output, 'bar');
+    });
   });
 
   describe('commonjs', function() {