Add support for assert statements with messages to the analyzer.

pkg/analyzer/test/generated/non_error_resolver_test.dart

 // Copyright (c) 2014, the Dart project authors.  Please see the AUTHORS file
 // 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.
 
 library engine.non_error_resolver_test;
 
 import 'package:analyzer/src/generated/ast.dart';
 import 'package:analyzer/src/generated/element.dart';
 import 'package:analyzer/src/generated/engine.dart';
 import 'package:analyzer/src/generated/error.dart';
@@ skipping 244 matching lines @@
     Source source = addSource(r'''
 typedef A(int p1, String p2);
 f(A a) {
   a(1, '2');
 }''');
     computeLibrarySourceErrors(source);
     assertNoErrors(source);
     verify([source]);
   }
 
+  void test_assert_with_message_await() {
+    resetWithOptions(new AnalysisOptionsImpl()..enableAssertMessage = true);
+    Source source = addSource('''
+import 'dart:async';
+f() async {
+  assert(false, await g());
+}
+Future<String> g() => null;
+''');
+    computeLibrarySourceErrors(source);
+    assertNoErrors(source);
+    verify([source]);
+  }
+
+  void test_assert_with_message_dynamic() {
+    resetWithOptions(new AnalysisOptionsImpl()..enableAssertMessage = true);
+    Source source = addSource('''
+f() {
+  assert(false, g());
+}
+g() => null;
+''');
+    computeLibrarySourceErrors(source);
+    assertNoErrors(source);
+    verify([source]);
+  }
+
+  void test_assert_with_message_null() {
+    resetWithOptions(new AnalysisOptionsImpl()..enableAssertMessage = true);
+    Source source = addSource('''
+f() {
+  assert(false, null);
+}
+''');
+    computeLibrarySourceErrors(source);
+    assertNoErrors(source);
+    verify([source]);
+  }
+
+  void test_assert_with_message_string() {
+    resetWithOptions(new AnalysisOptionsImpl()..enableAssertMessage = true);
+    Source source = addSource('''
+f() {
+  assert(false, 'message');
+}
+''');
+    computeLibrarySourceErrors(source);
+    assertNoErrors(source);
+    verify([source]);
+  }
+
+  void test_assert_with_message_suppresses_unused_var_hint() {
+    resetWithOptions(new AnalysisOptionsImpl()..enableAssertMessage = true);
+    Source source = addSource('''
+f() {
+  String message = 'msg';
+  assert(true, message);
+}
+''');
+    computeLibrarySourceErrors(source);
+    assertNoErrors(source);
+    verify([source]);
+  }
+
   void test_assignability_function_expr_rettype_from_typedef_cls() {
     // In the code below, the type of (() => f()) has a return type which is
     // a class, and that class is inferred from the return type of the typedef
     // F.
     Source source = addSource('''
 class C {}
 typedef C F();
 F f;
 main() {
   F f2 = (() => f());
@@ skipping 5479 matching lines @@
     reset();
   }
 
   void _check_wrongNumberOfParametersForOperator1(String name) {
     _check_wrongNumberOfParametersForOperator(name, "a");
   }
 
   CompilationUnit _getResolvedLibraryUnit(Source source) =>
       analysisContext.getResolvedCompilationUnit2(source, source);
 }