Add StringLengthConstantExpression

tests/compiler/dart2js/constant_expression_evaluate_test.dart

 // Copyright (c) 2015, 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 dart2js.constants.expressions.evaluate_test;
 
 import 'dart:async';
 import 'package:async_helper/async_helper.dart';
 import 'package:expect/expect.dart';
 import 'package:compiler/src/constants/expressions.dart';
@@ skipping 20 matching lines @@
   final Map<Map<String, String>, String> expectedValues;
 
   const ConstantData(this.code,
                      this.expectedValues);
 }
 
 class MemoryEnvironment implements Environment {
   final Compiler compiler;
   final Map<String, String> env;
 
-  MemoryEnvironment(this.compiler, [this.env = const <String, String>{}]);
+  MemoryEnvironment(this.compiler,
+                    [this.env = const <String, String>{}]);
 
   @override
   String readFromEnvironment(String name) => env[name];
 }
 
 const List<TestData> DATA = const [
   const TestData('', const [
     const ConstantData('null', const { const {} : 'NullConstant' }),
     const ConstantData('false', const { const {} : 'BoolConstant(false)' }),
     const ConstantData('true', const { const {} : 'BoolConstant(true)' }),
     const ConstantData('0', const { const {} : 'IntConstant(0)' }),
     const ConstantData('0.0', const { const {} : 'DoubleConstant(0.0)' }),
     const ConstantData('"foo"', const { const {} : 'StringConstant("foo")' }),
     const ConstantData('1 + 2', const { const {} : 'IntConstant(3)' }),
     const ConstantData('-(1)', const { const {} : 'IntConstant(-1)' }),
+    const ConstantData('"foo".length', const { const {} : 'IntConstant(3)' }),
     const ConstantData('identical(0, 1)',
                        const { const {} : 'BoolConstant(false)' }),
     const ConstantData('"a" "b"', const { const {} : 'StringConstant("ab")' }),
     const ConstantData('identical',
         const { const {} : 'FunctionConstant(identical)' }),
     const ConstantData('true ? 0 : 1', const { const {} : 'IntConstant(0)' }),
     const ConstantData('proxy',
         const { const {} : 'ConstructedConstant(_Proxy())' }),
     const ConstantData('Object', const { const {} : 'TypeConstant(Object)' }),
     const ConstantData('const [0, 1]',
@@ skipping 70 matching lines @@
           'ConstructedConstant(C(field1=BoolConstant(false),'
                                 'field2=IntConstant(87)))', }),
   ]),
   const TestData('''
 class A<T> implements B {
   final field1;
   const A({this.field1:42});
 }
 class B<S> implements C {
   const factory B({field1}) = A<B<S>>;
-  // TODO(johnniwinther): Enable this when the constructor evaluator doesn't
-  // crash:
-  /*const factory B.named() = A<S>;*/
+  const factory B.named() = A<S>;
 }
 class C<U> {
   const factory C({field1}) = A<B<double>>;
 }
 ''', const [
     const ConstantData('const A()',
         const { const {} :
           'ConstructedConstant(A<dynamic>(field1=IntConstant(42)))' }),
     const ConstantData('const A<int>(field1: 87)',
         const { const {} :
           'ConstructedConstant(A<int>(field1=IntConstant(87)))' }),
     const ConstantData('const B()',
         const { const {} :
           'ConstructedConstant(A<B<dynamic>>(field1=IntConstant(42)))' }),
     const ConstantData('const B<int>()',
         const { const {} :
           'ConstructedConstant(A<B<int>>(field1=IntConstant(42)))' }),
     const ConstantData('const B<int>(field1: 87)',
         const { const {} :
           'ConstructedConstant(A<B<int>>(field1=IntConstant(87)))' }),
     const ConstantData('const C<int>(field1: 87)',
         const { const {} :
           'ConstructedConstant(A<B<double>>(field1=IntConstant(87)))' }),
-    // TODO(johnniwinther): Enable this when the constructor evaluator doesn't
-    // crash:
-    /*const ConstantData('const B<int>.named()',
+    const ConstantData('const B<int>.named()',
         const { const {} :
-          'ConstructedConstant(A<int>(field1=IntConstant(42)))' }),*/
+          'ConstructedConstant(A<int>(field1=IntConstant(42)))' }),
   ]),
   const TestData('''
 const c = const int.fromEnvironment("foo", defaultValue: 5);
 const d = const int.fromEnvironment("bar", defaultValue: 10);
 
 class A {
   final field;
   const A(a, b) : field = a + b;
 }
 
@@ skipping 42 matching lines @@
         ConstantValue value =
             constant.evaluate(environment, DART_CONSTANT_SYSTEM);
         String valueText = value.toStructuredString();
         Expect.equals(expectedText, valueText,
             "Unexpected value '${valueText}' for contant "
             "`${constant.getText()}`, expected '${expectedText}'.");
       });
     });
   });
 }