Fix for conditional expressions

test/checker/checker_test.dart

Index: test/checker/checker_test.dart
diff --git a/test/checker/checker_test.dart b/test/checker/checker_test.dart
index 30995002972b9f56a08a69cbd33a9a3fc7ff7bb9..c26bbf3bf7c2fbda7ff40926005a8375f9155ff7 100644
--- a/test/checker/checker_test.dart
+++ b/test/checker/checker_test.dart
@@ -1548,6 +1548,20 @@ main() {
     testChecker({'/main.dart': mk("info:DownCast")}, allowConstCasts: true);
   });
 
+  test('casts in conditionals', () {
+    testChecker({
+      '/main.dart': '''
+          main() {
+            bool b = true;
+            num x = b ? 1 : 2.3;
+            int y = /*info:DownCast*/b ? 1 : 2.3;
+            String z = !b ? "hello" : null;
+            z = b ? null : "hello";
+          }
+      '''
+    });
+  });
+
   test('redirecting constructor', () {
     testChecker({
       '/main.dart': '''