Add support for assert statements with messages to the analyzer.

pkg/analyzer/test/generated/compile_time_error_code_test.dart

Index: pkg/analyzer/test/generated/compile_time_error_code_test.dart
diff --git a/pkg/analyzer/test/generated/compile_time_error_code_test.dart b/pkg/analyzer/test/generated/compile_time_error_code_test.dart
index 2028e70a038534e5887dd66b1d18cfca96545ccf..0fb58431c2c116e04aea97b46339ece45ed01f16 100644
--- a/pkg/analyzer/test/generated/compile_time_error_code_test.dart
+++ b/pkg/analyzer/test/generated/compile_time_error_code_test.dart
@@ -222,6 +222,19 @@ class N {}''');
     verify([source]);
   }
 
+  void test_assertWithExtraArgument() {
+    // TODO(paulberry): once DEP 37 is turned on by default, this test should
+    // be removed.
+    Source source = addSource('''
+f(bool x) {
+  assert(x, 'foo');
+}
+''');
+    computeLibrarySourceErrors(source);
+    assertErrors(source, [CompileTimeErrorCode.EXTRA_ARGUMENT_TO_ASSERT]);
+    verify([source]);
+  }
+
   void test_async_used_as_identifier_in_annotation() {
     Source source = addSource('''
 const int async = 0;