add support for type cast expressions - fixes babel/babel-eslint#102

eslint/babel-eslint-parser/acorn-to-esprima.js

@@ -171,6 +171,10 @@ var astTransformVisitor = {
       delete node.argument;
     }
 
+    if (t.isTypeCastExpression(node)) {
+      return node.expression;
+    }
+
     if (t.isFlow(node)) {
       return this.remove();
     }

eslint/babel-eslint-parser/test/non-regression.js

@@ -124,6 +124,14 @@ describe("verify", function () {
     );
   });
 
+  it("type cast expression", function () {
+    verifyAndAssertMessages(
+      "for (let a of (a: Array)) {}",
+      {},
+      []
+    );
+  });
+
   it("class usage", function () {
     verifyAndAssertMessages(
       "class Lol {} module.exports = Lol;",