Implementation of null-aware operators.

tests/compiler/dart2js_extra/conditional_send_test.dart

Index: tests/compiler/dart2js_extra/conditional_send_test.dart
diff --git a/tests/language/issue13179_test.dart b/tests/compiler/dart2js_extra/conditional_send_test.dart
similarity index 53%
copy from tests/language/issue13179_test.dart
copy to tests/compiler/dart2js_extra/conditional_send_test.dart
index 0439ceab895f5925234763b90cb323007bc19b14..c95203d244861f2861d83148405a0f1d7ddd6e7b 100644
--- a/tests/language/issue13179_test.dart
+++ b/tests/compiler/dart2js_extra/conditional_send_test.dart
@@ -2,18 +2,19 @@
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
+// SharedOptions=--enable-null-aware-operators
 import "package:expect/expect.dart";
 
-int count = 0;
+@NoInline() @AssumeDynamic()
+confuse(x) => x;
 
-void f([void f([x]) = f]) {
-  count++;
-  if (f != null) {
-    f(null);
-  }
+class A {
+  int x;
+  m() => "a";
 }
 
-main() {
-  f();
-  Expect.equals(2, count);
+main(args) {
+  var a = confuse(true) ? null : new A();
+  a?.x = 3;
+  Expect.throws(() => a.m());
 }