Handle parenthesized expression in type promotion.

tests/language/type_promotion_closure_test.dart

Index: tests/language/type_promotion_closure_test.dart
diff --git a/tests/language/type_promotion_closure_test.dart b/tests/language/type_promotion_closure_test.dart
index bb514daaf2196a180dbd4b8ccf3f9f6da6c4db1d..5c594439f65d03d3f6bedf6fcbd86097fea1a7e6 100644
--- a/tests/language/type_promotion_closure_test.dart
+++ b/tests/language/type_promotion_closure_test.dart
@@ -30,9 +30,11 @@ void main() {
   test1();
   test2();
   test3();
+  test3a();
   test4();
   test5();
   test6();
+  test6a();
   test7();
   test8();
   test9();
@@ -79,6 +81,22 @@ void test3() {
   }
 }
 
+void test3a() {
+  A a = new E();
+  void foo() {
+    a = new D();
+  }
+  if ((((a)) is B)) {
+    print(a.a);
+    print(a.b); /// 15: static type warning
+    void foo() {
+      a = new D();
+    }
+    print(a.a);
+    print(a.b); /// 16: static type warning
+  }
+}
+
 void test4() {
   A a = new E();
   if (a is B) {
@@ -107,6 +125,16 @@ void test6() {
   a = null;
 }
 
+void test6a() {
+  A a = new E();
+  if (((a) is B)) {
+    func(() => a);
+    print(a.a);
+    print(a.b); /// 14: static type warning
+  }
+  a = null;
+}
+
 void test7() {
   A a = new E();
   if (a is B && func(() => a)) {