Fix issue webpack#3238

Diogo Franco (Kovensky) · Diogo Franco (Kovensky) · commit 996a4b660bb2 · 2016-11-08T10:40:34.000+09:00
diff --git a/lib/Parser.js b/lib/Parser.js
@@ -909,7 +909,7 @@ Parser.prototype.inScope = function inScope(params, fn) {
 };
 
 Parser.prototype.enterPattern = function enterPattern(pattern, onIdent) {
-	if(this["enter" + pattern.type])
+	if(pattern != null && this["enter" + pattern.type])
 		return this["enter" + pattern.type](pattern, onIdent);
 };
 
diff --git a/test/cases/parsing/issue-3238/index.js b/test/cases/parsing/issue-3238/index.js
@@ -0,0 +1,4 @@
+it("should pass", function() {
+  const second = ([, x]) => x;
+  second([1, 2]).should.eql(2);
+});
