strawman fix for #953

src/ast/nodes/shared/isUsedByBundle.js

@@ -3,22 +3,11 @@ import { UNKNOWN } from '../../values.js';
 export default function isUsedByBundle ( scope, node ) {
 	while ( node.type === 'ParenthesizedExpression' ) node = node.expression;
 
-	// const expression = node;
-	while ( node.type === 'MemberExpression' ) node = node.object;
-
-	const declaration = scope.findDeclaration( node.name );
-
-	if ( declaration.isParam ) {
-		return true;
-
-		// TODO if we mutate a parameter, assume the worst
-		// return node !== expression;
-	}
-
-	if ( declaration.activated ) return true;
+	// TODO do we need to distinguish between assignments and mutations somehow?
+	if ( node.type === 'MemberExpression' ) node = node.object;
 
 	const values = new Set();
-	declaration.gatherPossibleValues( values );
+	node.gatherPossibleValues( values );
 	for ( const value of values ) {
 		if ( value === UNKNOWN ) {
 			return true;

test/function/mutate-aliased-property/_config.js

@@ -0,0 +1,3 @@
+module.exports = {
+	// solo: true
+};

test/function/mutate-aliased-property/main.js

@@ -0,0 +1,14 @@
+var Foo = (function() {
+	function Foo() {}
+	Foo.prototype.toString = function() { return 'foo'; };
+	return Foo;
+}());
+
+var Bar = (function() {
+	function Bar() {}
+	Bar.prototype = Foo.prototype;
+	Bar.prototype.toString = function() { return 'bar'; };
+	return Bar;
+}());
+
+assert.equal( new Foo().toString(), 'bar' );