Move constant implementation out of generated

pkg/analyzer/test/src/dart/constant/evaluation_test.dart

+// Copyright (c) 2016, 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 analyzer.test.constant_test;
+
+import 'package:analyzer/context/declared_variables.dart';
+import 'package:analyzer/dart/ast/ast.dart';
+import 'package:analyzer/dart/ast/token.dart';
+import 'package:analyzer/dart/element/element.dart';
+import 'package:analyzer/src/dart/element/element.dart';
+import 'package:analyzer/src/generated/constant.dart';
+import 'package:analyzer/src/generated/engine.dart';
+import 'package:analyzer/src/generated/error.dart';
+import 'package:analyzer/src/generated/resolver.dart';
+import 'package:analyzer/src/generated/source.dart';
+import 'package:analyzer/src/generated/source_io.dart';
+import 'package:analyzer/src/generated/testing/ast_factory.dart';
+import 'package:analyzer/src/generated/testing/test_type_provider.dart';
+import 'package:analyzer/src/task/dart.dart';
+import 'package:path/path.dart';
+import 'package:unittest/unittest.dart';
+
+import '../../../generated/resolver_test_case.dart';
+import '../../../generated/test_support.dart';
+import '../../../reflective_tests.dart';
+import '../../../utils.dart';
+
+main() {
+  initializeTestEnvironment();
+  runReflectiveTests(ConstantValueComputerTest);
+  runReflectiveTests(ConstantVisitorTest);
+}
+
+/**
+ * Implementation of [ConstantEvaluationValidator] used during unit tests;
+ * verifies that any nodes referenced during constant evaluation are present in
+ * the dependency graph.
+ */
+class ConstantEvaluationValidator_ForTest
+    implements ConstantEvaluationValidator {
+  final InternalAnalysisContext context;
+  ConstantValueComputer computer;
+  ConstantEvaluationTarget _nodeBeingEvaluated;
+
+  ConstantEvaluationValidator_ForTest(this.context);
+
+  @override
+  void beforeComputeValue(ConstantEvaluationTarget constant) {
+    _nodeBeingEvaluated = constant;
+  }
+
+  @override
+  void beforeGetConstantInitializers(ConstructorElement constructor) =>
+      _checkPathTo(constructor);
+
+  @override
+  void beforeGetEvaluationResult(ConstantEvaluationTarget constant) =>
+      _checkPathTo(constant);
+
+  @override
+  void beforeGetFieldEvaluationResult(FieldElementImpl field) =>
+      _checkPathTo(field);
+
+  @override
+  void beforeGetParameterDefault(ParameterElement parameter) =>
+      _checkPathTo(parameter);
+
+  void _checkPathTo(ConstantEvaluationTarget target) {
+    if (computer.referenceGraph.containsPath(_nodeBeingEvaluated, target)) {
+      return; // pass
+    }
+    // print a nice error message on failure
+    StringBuffer out = new StringBuffer();
+    out.writeln("missing path in constant dependency graph");
+    out.writeln("from $_nodeBeingEvaluated to $target");
+    for (var s in context.analysisCache.sources) {
+      String text = context.getContents(s).data;
+      if (text != "") {
+        out.writeln('''
+=== ${s.shortName}
+$text''');
+      }
+    }
+    fail(out.toString());
+  }
+}
+
+@reflectiveTest
+class ConstantValueComputerTest extends ResolverTestCase {
+  void test_annotation_constConstructor() {
+    CompilationUnit compilationUnit = resolveSource(r'''
+class A {
+  final int i;
+  const A(this.i);
+}
+
+class C {
+  @A(5)
+  f() {}
+}
+''');
+    EvaluationResultImpl result =
+        _evaluateAnnotation(compilationUnit, "C", "f");
+    Map<String, DartObjectImpl> annotationFields = _assertType(result, 'A');
+    _assertIntField(annotationFields, 'i', 5);
+  }
+
+  void test_annotation_constConstructor_named() {
+    CompilationUnit compilationUnit = resolveSource(r'''
+class A {
+  final int i;
+  const A.named(this.i);
+}
+
+class C {
+  @A.named(5)
+  f() {}
+}
+''');
+    EvaluationResultImpl result =
+        _evaluateAnnotation(compilationUnit, "C", "f");
+    Map<String, DartObjectImpl> annotationFields = _assertType(result, 'A');
+    _assertIntField(annotationFields, 'i', 5);
+  }
+
+  void test_annotation_constConstructor_noArgs() {
+    // Failing to pass arguments to an annotation which is a constant
+    // constructor is illegal, but shouldn't crash analysis.
+    CompilationUnit compilationUnit = resolveSource(r'''
+class A {
+  final int i;
+  const A(this.i);
+}
+
+class C {
+  @A
+  f() {}
+}
+''');
+    _evaluateAnnotation(compilationUnit, "C", "f");
+  }
+
+  void test_annotation_constConstructor_noArgs_named() {
+    // Failing to pass arguments to an annotation which is a constant
+    // constructor is illegal, but shouldn't crash analysis.
+    CompilationUnit compilationUnit = resolveSource(r'''
+class A {
+  final int i;
+  const A.named(this.i);
+}
+
+class C {
+  @A.named
+  f() {}
+}
+''');
+    _evaluateAnnotation(compilationUnit, "C", "f");
+  }
+
+  void test_annotation_nonConstConstructor() {
+    // Calling a non-const constructor from an annotation that is illegal, but
+    // shouldn't crash analysis.
+    CompilationUnit compilationUnit = resolveSource(r'''
+class A {
+  final int i;
+  A(this.i);
+}
+
+class C {
+  @A(5)
+  f() {}
+}
+''');
+    _evaluateAnnotation(compilationUnit, "C", "f");
+  }
+
+  void test_annotation_staticConst() {
+    CompilationUnit compilationUnit = resolveSource(r'''
+class C {
+  static const int i = 5;
+
+  @i
+  f() {}
+}
+''');
+    EvaluationResultImpl result =
+        _evaluateAnnotation(compilationUnit, "C", "f");
+    expect(_assertValidInt(result), 5);
+  }
+
+  void test_annotation_staticConst_args() {
+    // Applying arguments to an annotation that is a static const is
+    // illegal, but shouldn't crash analysis.
+    CompilationUnit compilationUnit = resolveSource(r'''
+class C {
+  static const int i = 5;
+
+  @i(1)
+  f() {}
+}
+''');
+    _evaluateAnnotation(compilationUnit, "C", "f");
+  }
+
+  void test_annotation_staticConst_otherClass() {
+    CompilationUnit compilationUnit = resolveSource(r'''
+class A {
+  static const int i = 5;
+}
+
+class C {
+  @A.i
+  f() {}
+}
+''');
+    EvaluationResultImpl result =
+        _evaluateAnnotation(compilationUnit, "C", "f");
+    expect(_assertValidInt(result), 5);
+  }
+
+  void test_annotation_staticConst_otherClass_args() {
+    // Applying arguments to an annotation that is a static const is
+    // illegal, but shouldn't crash analysis.
+    CompilationUnit compilationUnit = resolveSource(r'''
+class A {
+  static const int i = 5;
+}
+
+class C {
+  @A.i(1)
+  f() {}
+}
+''');
+    _evaluateAnnotation(compilationUnit, "C", "f");
+  }
+
+  void test_annotation_topLevelVariable() {
+    CompilationUnit compilationUnit = resolveSource(r'''
+const int i = 5;
+class C {
+  @i
+  f() {}
+}
+''');
+    EvaluationResultImpl result =
+        _evaluateAnnotation(compilationUnit, "C", "f");
+    expect(_assertValidInt(result), 5);
+  }
+
+  void test_annotation_topLevelVariable_args() {
+    // Applying arguments to an annotation that is a top-level variable is
+    // illegal, but shouldn't crash analysis.
+    CompilationUnit compilationUnit = resolveSource(r'''
+const int i = 5;
+class C {
+  @i(1)
+  f() {}
+}
+''');
+    _evaluateAnnotation(compilationUnit, "C", "f");
+  }
+
+  void test_computeValues_cycle() {
+    TestLogger logger = new TestLogger();
+    AnalysisEngine.instance.logger = logger;
+    try {
+      Source source = addSource(r'''
+  const int a = c;
+  const int b = a;
+  const int c = b;''');
+      LibraryElement libraryElement = resolve2(source);
+      CompilationUnit unit =
+          analysisContext.resolveCompilationUnit(source, libraryElement);
+      analysisContext.computeErrors(source);
+      expect(unit, isNotNull);
+      ConstantValueComputer computer = _makeConstantValueComputer();
+      computer.add(unit, source, source);
+      computer.computeValues();
+      NodeList<CompilationUnitMember> members = unit.declarations;
+      expect(members, hasLength(3));
+      _validate(false, (members[0] as TopLevelVariableDeclaration).variables);
+      _validate(false, (members[1] as TopLevelVariableDeclaration).variables);
+      _validate(false, (members[2] as TopLevelVariableDeclaration).variables);
+    } finally {
+      AnalysisEngine.instance.logger = Logger.NULL;
+    }
+  }
+
+  void test_computeValues_dependentVariables() {
+    Source source = addSource(r'''
+const int b = a;
+const int a = 0;''');
+    LibraryElement libraryElement = resolve2(source);
+    CompilationUnit unit =
+        analysisContext.resolveCompilationUnit(source, libraryElement);
+    expect(unit, isNotNull);
+    ConstantValueComputer computer = _makeConstantValueComputer();
+    computer.add(unit, source, source);
+    computer.computeValues();
+    NodeList<CompilationUnitMember> members = unit.declarations;
+    expect(members, hasLength(2));
+    _validate(true, (members[0] as TopLevelVariableDeclaration).variables);
+    _validate(true, (members[1] as TopLevelVariableDeclaration).variables);
+  }
+
+  void test_computeValues_empty() {
+    ConstantValueComputer computer = _makeConstantValueComputer();
+    computer.computeValues();
+  }
+
+  void test_computeValues_multipleSources() {
+    Source librarySource = addNamedSource(
+        "/lib.dart",
+        r'''
+library lib;
+part 'part.dart';
+const int c = b;
+const int a = 0;''');
+    Source partSource = addNamedSource(
+        "/part.dart",
+        r'''
+part of lib;
+const int b = a;
+const int d = c;''');
+    LibraryElement libraryElement = resolve2(librarySource);
+    CompilationUnit libraryUnit =
+        analysisContext.resolveCompilationUnit(librarySource, libraryElement);
+    expect(libraryUnit, isNotNull);
+    CompilationUnit partUnit =
+        analysisContext.resolveCompilationUnit(partSource, libraryElement);
+    expect(partUnit, isNotNull);
+    ConstantValueComputer computer = _makeConstantValueComputer();
+    computer.add(libraryUnit, librarySource, librarySource);
+    computer.add(partUnit, partSource, librarySource);
+    computer.computeValues();
+    NodeList<CompilationUnitMember> libraryMembers = libraryUnit.declarations;
+    expect(libraryMembers, hasLength(2));
+    _validate(
+        true, (libraryMembers[0] as TopLevelVariableDeclaration).variables);
+    _validate(
+        true, (libraryMembers[1] as TopLevelVariableDeclaration).variables);
+    NodeList<CompilationUnitMember> partMembers = libraryUnit.declarations;
+    expect(partMembers, hasLength(2));
+    _validate(true, (partMembers[0] as TopLevelVariableDeclaration).variables);
+    _validate(true, (partMembers[1] as TopLevelVariableDeclaration).variables);
+  }
+
+  void test_computeValues_singleVariable() {
+    Source source = addSource("const int a = 0;");
+    LibraryElement libraryElement = resolve2(source);
+    CompilationUnit unit =
+        analysisContext.resolveCompilationUnit(source, libraryElement);
+    expect(unit, isNotNull);
+    ConstantValueComputer computer = _makeConstantValueComputer();
+    computer.add(unit, source, source);
+    computer.computeValues();
+    NodeList<CompilationUnitMember> members = unit.declarations;
+    expect(members, hasLength(1));
+    _validate(true, (members[0] as TopLevelVariableDeclaration).variables);
+  }
+
+  void test_computeValues_value_depends_on_enum() {
+    Source source = addSource('''
+enum E { id0, id1 }
+const E e = E.id0;
+''');
+    LibraryElement libraryElement = resolve2(source);
+    CompilationUnit unit =
+        analysisContext.resolveCompilationUnit(source, libraryElement);
+    expect(unit, isNotNull);
+    ConstantValueComputer computer = _makeConstantValueComputer();
+    computer.add(unit, source, source);
+    computer.computeValues();
+    TopLevelVariableDeclaration declaration = unit.declarations
+        .firstWhere((member) => member is TopLevelVariableDeclaration);
+    _validate(true, declaration.variables);
+  }
+
+  void test_dependencyOnConstructor() {
+    // x depends on "const A()"
+    _assertProperDependencies(r'''
+class A {
+  const A();
+}
+const x = const A();''');
+  }
+
+  void test_dependencyOnConstructorArgument() {
+    // "const A(x)" depends on x
+    _assertProperDependencies(r'''
+class A {
+  const A(this.next);
+  final A next;
+}
+const A x = const A(null);
+const A y = const A(x);''');
+  }
+
+  void test_dependencyOnConstructorArgument_unresolvedConstructor() {
+    // "const A.a(x)" depends on x even if the constructor A.a can't be found.
+    _assertProperDependencies(
+        r'''
+class A {
+}
+const int x = 1;
+const A y = const A.a(x);''',
+        [CompileTimeErrorCode.CONST_WITH_UNDEFINED_CONSTRUCTOR]);
+  }
+
+  void test_dependencyOnConstructorInitializer() {
+    // "const A()" depends on x
+    _assertProperDependencies(r'''
+const int x = 1;
+class A {
+  const A() : v = x;
+  final int v;
+}''');
+  }
+
+  void test_dependencyOnExplicitSuperConstructor() {
+    // b depends on B() depends on A()
+    _assertProperDependencies(r'''
+class A {
+  const A(this.x);
+  final int x;
+}
+class B extends A {
+  const B() : super(5);
+}
+const B b = const B();''');
+  }
+
+  void test_dependencyOnExplicitSuperConstructorParameters() {
+    // b depends on B() depends on i
+    _assertProperDependencies(r'''
+class A {
+  const A(this.x);
+  final int x;
+}
+class B extends A {
+  const B() : super(i);
+}
+const B b = const B();
+const int i = 5;''');
+  }
+
+  void test_dependencyOnFactoryRedirect() {
+    // a depends on A.foo() depends on A.bar()
+    _assertProperDependencies(r'''
+const A a = const A.foo();
+class A {
+  factory const A.foo() = A.bar;
+  const A.bar();
+}''');
+  }
+
+  void test_dependencyOnFactoryRedirectWithTypeParams() {
+    _assertProperDependencies(r'''
+class A {
+  const factory A(var a) = B<int>;
+}
+
+class B<T> implements A {
+  final T x;
+  const B(this.x);
+}
+
+const A a = const A(10);''');
+  }
+
+  void test_dependencyOnImplicitSuperConstructor() {
+    // b depends on B() depends on A()
+    _assertProperDependencies(r'''
+class A {
+  const A() : x = 5;
+  final int x;
+}
+class B extends A {
+  const B();
+}
+const B b = const B();''');
+  }
+
+  void test_dependencyOnInitializedFinal() {
+    // a depends on A() depends on A.x
+    _assertProperDependencies('''
+class A {
+  const A();
+  final int x = 1;
+}
+const A a = const A();
+''');
+  }
+
+  void test_dependencyOnInitializedNonStaticConst() {
+    // Even though non-static consts are not allowed by the language, we need
+    // to handle them for error recovery purposes.
+    // a depends on A() depends on A.x
+    _assertProperDependencies(
+        '''
+class A {
+  const A();
+  const int x = 1;
+}
+const A a = const A();
+''',
+        [CompileTimeErrorCode.CONST_INSTANCE_FIELD]);
+  }
+
+  void test_dependencyOnNonFactoryRedirect() {
+    // a depends on A.foo() depends on A.bar()
+    _assertProperDependencies(r'''
+const A a = const A.foo();
+class A {
+  const A.foo() : this.bar();
+  const A.bar();
+}''');
+  }
+
+  void test_dependencyOnNonFactoryRedirect_arg() {
+    // a depends on A.foo() depends on b
+    _assertProperDependencies(r'''
+const A a = const A.foo();
+const int b = 1;
+class A {
+  const A.foo() : this.bar(b);
+  const A.bar(x) : y = x;
+  final int y;
+}''');
+  }
+
+  void test_dependencyOnNonFactoryRedirect_defaultValue() {
+    // a depends on A.foo() depends on A.bar() depends on b
+    _assertProperDependencies(r'''
+const A a = const A.foo();
+const int b = 1;
+class A {
+  const A.foo() : this.bar();
+  const A.bar([x = b]) : y = x;
+  final int y;
+}''');
+  }
+
+  void test_dependencyOnNonFactoryRedirect_toMissing() {
+    // a depends on A.foo() which depends on nothing, since A.bar() is
+    // missing.
+    _assertProperDependencies(
+        r'''
+const A a = const A.foo();
+class A {
+  const A.foo() : this.bar();
+}''',
+        [CompileTimeErrorCode.REDIRECT_GENERATIVE_TO_MISSING_CONSTRUCTOR]);
+  }
+
+  void test_dependencyOnNonFactoryRedirect_toNonConst() {
+    // a depends on A.foo() which depends on nothing, since A.bar() is
+    // non-const.
+    _assertProperDependencies(r'''
+const A a = const A.foo();
+class A {
+  const A.foo() : this.bar();
+  A.bar();
+}''');
+  }
+
+  void test_dependencyOnNonFactoryRedirect_unnamed() {
+    // a depends on A.foo() depends on A()
+    _assertProperDependencies(r'''
+const A a = const A.foo();
+class A {
+  const A.foo() : this();
+  const A();
+}''');
+  }
+
+  void test_dependencyOnOptionalParameterDefault() {
+    // a depends on A() depends on B()
+    _assertProperDependencies(r'''
+class A {
+  const A([x = const B()]) : b = x;
+  final B b;
+}
+class B {
+  const B();
+}
+const A a = const A();''');
+  }
+
+  void test_dependencyOnVariable() {
+    // x depends on y
+    _assertProperDependencies(r'''
+const x = y + 1;
+const y = 2;''');
+  }
+
+  void test_final_initialized_at_declaration() {
+    CompilationUnit compilationUnit = resolveSource('''
+class A {
+  final int i = 123;
+  const A();
+}
+
+const A a = const A();
+''');
+    EvaluationResultImpl result =
+        _evaluateTopLevelVariable(compilationUnit, 'a');
+    Map<String, DartObjectImpl> fields = _assertType(result, "A");
+    expect(fields, hasLength(1));
+    _assertIntField(fields, "i", 123);
+  }
+
+  void test_fromEnvironment_bool_default_false() {
+    expect(_assertValidBool(_check_fromEnvironment_bool(null, "false")), false);
+  }
+
+  void test_fromEnvironment_bool_default_overridden() {
+    expect(
+        _assertValidBool(_check_fromEnvironment_bool("false", "true")), false);
+  }
+
+  void test_fromEnvironment_bool_default_parseError() {
+    expect(_assertValidBool(_check_fromEnvironment_bool("parseError", "true")),
+        true);
+  }
+
+  void test_fromEnvironment_bool_default_true() {
+    expect(_assertValidBool(_check_fromEnvironment_bool(null, "true")), true);
+  }
+
+  void test_fromEnvironment_bool_false() {
+    expect(_assertValidBool(_check_fromEnvironment_bool("false", null)), false);
+  }
+
+  void test_fromEnvironment_bool_parseError() {
+    expect(_assertValidBool(_check_fromEnvironment_bool("parseError", null)),
+        false);
+  }
+
+  void test_fromEnvironment_bool_true() {
+    expect(_assertValidBool(_check_fromEnvironment_bool("true", null)), true);
+  }
+
+  void test_fromEnvironment_bool_undeclared() {
+    _assertValidUnknown(_check_fromEnvironment_bool(null, null));
+  }
+
+  void test_fromEnvironment_int_default_overridden() {
+    expect(_assertValidInt(_check_fromEnvironment_int("234", "123")), 234);
+  }
+
+  void test_fromEnvironment_int_default_parseError() {
+    expect(
+        _assertValidInt(_check_fromEnvironment_int("parseError", "123")), 123);
+  }
+
+  void test_fromEnvironment_int_default_undeclared() {
+    expect(_assertValidInt(_check_fromEnvironment_int(null, "123")), 123);
+  }
+
+  void test_fromEnvironment_int_ok() {
+    expect(_assertValidInt(_check_fromEnvironment_int("234", null)), 234);
+  }
+
+  void test_fromEnvironment_int_parseError() {
+    _assertValidNull(_check_fromEnvironment_int("parseError", null));
+  }
+
+  void test_fromEnvironment_int_parseError_nullDefault() {
+    _assertValidNull(_check_fromEnvironment_int("parseError", "null"));
+  }
+
+  void test_fromEnvironment_int_undeclared() {
+    _assertValidUnknown(_check_fromEnvironment_int(null, null));
+  }
+
+  void test_fromEnvironment_int_undeclared_nullDefault() {
+    _assertValidNull(_check_fromEnvironment_int(null, "null"));
+  }
+
+  void test_fromEnvironment_string_default_overridden() {
+    expect(_assertValidString(_check_fromEnvironment_string("abc", "'def'")),
+        "abc");
+  }
+
+  void test_fromEnvironment_string_default_undeclared() {
+    expect(_assertValidString(_check_fromEnvironment_string(null, "'def'")),
+        "def");
+  }
+
+  void test_fromEnvironment_string_empty() {
+    expect(_assertValidString(_check_fromEnvironment_string("", null)), "");
+  }
+
+  void test_fromEnvironment_string_ok() {
+    expect(
+        _assertValidString(_check_fromEnvironment_string("abc", null)), "abc");
+  }
+
+  void test_fromEnvironment_string_undeclared() {
+    _assertValidUnknown(_check_fromEnvironment_string(null, null));
+  }
+
+  void test_fromEnvironment_string_undeclared_nullDefault() {
+    _assertValidNull(_check_fromEnvironment_string(null, "null"));
+  }
+
+  void test_instanceCreationExpression_computedField() {
+    CompilationUnit compilationUnit = resolveSource(r'''
+const foo = const A(4, 5);
+class A {
+  const A(int i, int j) : k = 2 * i + j;
+  final int k;
+}''');
+    EvaluationResultImpl result =
+        _evaluateTopLevelVariable(compilationUnit, "foo");
+    Map<String, DartObjectImpl> fields = _assertType(result, "A");
+    expect(fields, hasLength(1));
+    _assertIntField(fields, "k", 13);
+  }
+
+  void
+      test_instanceCreationExpression_computedField_namedOptionalWithDefault() {
+    _checkInstanceCreationOptionalParams(false, true, true);
+  }
+
+  void
+      test_instanceCreationExpression_computedField_namedOptionalWithoutDefault() {
+    _checkInstanceCreationOptionalParams(false, true, false);
+  }
+
+  void
+      test_instanceCreationExpression_computedField_unnamedOptionalWithDefault() {
+    _checkInstanceCreationOptionalParams(false, false, true);
+  }
+
+  void
+      test_instanceCreationExpression_computedField_unnamedOptionalWithoutDefault() {
+    _checkInstanceCreationOptionalParams(false, false, false);
+  }
+
+  void test_instanceCreationExpression_computedField_usesConstConstructor() {
+    CompilationUnit compilationUnit = resolveSource(r'''
+const foo = const A(3);
+class A {
+  const A(int i) : b = const B(4);
+  final int b;
+}
+class B {
+  const B(this.k);
+  final int k;
+}''');
+    EvaluationResultImpl result =
+        _evaluateTopLevelVariable(compilationUnit, "foo");
+    Map<String, DartObjectImpl> fieldsOfA = _assertType(result, "A");
+    expect(fieldsOfA, hasLength(1));
+    Map<String, DartObjectImpl> fieldsOfB =
+        _assertFieldType(fieldsOfA, "b", "B");
+    expect(fieldsOfB, hasLength(1));
+    _assertIntField(fieldsOfB, "k", 4);
+  }
+
+  void test_instanceCreationExpression_computedField_usesStaticConst() {
+    CompilationUnit compilationUnit = resolveSource(r'''
+const foo = const A(3);
+class A {
+  const A(int i) : k = i + B.bar;
+  final int k;
+}
+class B {
+  static const bar = 4;
+}''');
+    EvaluationResultImpl result =
+        _evaluateTopLevelVariable(compilationUnit, "foo");
+    Map<String, DartObjectImpl> fields = _assertType(result, "A");
+    expect(fields, hasLength(1));
+    _assertIntField(fields, "k", 7);
+  }
+
+  void test_instanceCreationExpression_computedField_usesTopLevelConst() {
+    CompilationUnit compilationUnit = resolveSource(r'''
+const foo = const A(3);
+const bar = 4;
+class A {
+  const A(int i) : k = i + bar;
+  final int k;
+}''');
+    EvaluationResultImpl result =
+        _evaluateTopLevelVariable(compilationUnit, "foo");
+    Map<String, DartObjectImpl> fields = _assertType(result, "A");
+    expect(fields, hasLength(1));
+    _assertIntField(fields, "k", 7);
+  }
+
+  void test_instanceCreationExpression_explicitSuper() {
+    CompilationUnit compilationUnit = resolveSource(r'''
+const foo = const B(4, 5);
+class A {
+  const A(this.x);
+  final int x;
+}
+class B extends A {
+  const B(int x, this.y) : super(x * 2);
+  final int y;
+}''');
+    EvaluationResultImpl result =
+        _evaluateTopLevelVariable(compilationUnit, "foo");
+    Map<String, DartObjectImpl> fields = _assertType(result, "B");
+    expect(fields, hasLength(2));
+    _assertIntField(fields, "y", 5);
+    Map<String, DartObjectImpl> superclassFields =
+        _assertFieldType(fields, GenericState.SUPERCLASS_FIELD, "A");
+    expect(superclassFields, hasLength(1));
+    _assertIntField(superclassFields, "x", 8);
+  }
+
+  void test_instanceCreationExpression_fieldFormalParameter() {
+    CompilationUnit compilationUnit = resolveSource(r'''
+const foo = const A(42);
+class A {
+  int x;
+  const A(this.x)
+}''');
+    EvaluationResultImpl result =
+        _evaluateTopLevelVariable(compilationUnit, "foo");
+    Map<String, DartObjectImpl> fields = _assertType(result, "A");
+    expect(fields, hasLength(1));
+    _assertIntField(fields, "x", 42);
+  }
+
+  void
+      test_instanceCreationExpression_fieldFormalParameter_namedOptionalWithDefault() {
+    _checkInstanceCreationOptionalParams(true, true, true);
+  }
+
+  void
+      test_instanceCreationExpression_fieldFormalParameter_namedOptionalWithoutDefault() {
+    _checkInstanceCreationOptionalParams(true, true, false);
+  }
+
+  void
+      test_instanceCreationExpression_fieldFormalParameter_unnamedOptionalWithDefault() {
+    _checkInstanceCreationOptionalParams(true, false, true);
+  }
+
+  void
+      test_instanceCreationExpression_fieldFormalParameter_unnamedOptionalWithoutDefault() {
+    _checkInstanceCreationOptionalParams(true, false, false);
+  }
+
+  void test_instanceCreationExpression_implicitSuper() {
+    CompilationUnit compilationUnit = resolveSource(r'''
+const foo = const B(4);
+class A {
+  const A() : x = 3;
+  final int x;
+}
+class B extends A {
+  const B(this.y);
+  final int y;
+}''');
+    EvaluationResultImpl result =
+        _evaluateTopLevelVariable(compilationUnit, "foo");
+    Map<String, DartObjectImpl> fields = _assertType(result, "B");
+    expect(fields, hasLength(2));
+    _assertIntField(fields, "y", 4);
+    Map<String, DartObjectImpl> superclassFields =
+        _assertFieldType(fields, GenericState.SUPERCLASS_FIELD, "A");
+    expect(superclassFields, hasLength(1));
+    _assertIntField(superclassFields, "x", 3);
+  }
+
+  void test_instanceCreationExpression_nonFactoryRedirect() {
+    CompilationUnit compilationUnit = resolveSource(r'''
+const foo = const A.a1();
+class A {
+  const A.a1() : this.a2();
+  const A.a2() : x = 5;
+  final int x;
+}''');
+    Map<String, DartObjectImpl> aFields =
+        _assertType(_evaluateTopLevelVariable(compilationUnit, "foo"), "A");
+    _assertIntField(aFields, 'x', 5);
+  }
+
+  void test_instanceCreationExpression_nonFactoryRedirect_arg() {
+    CompilationUnit compilationUnit = resolveSource(r'''
+const foo = const A.a1(1);
+class A {
+  const A.a1(x) : this.a2(x + 100);
+  const A.a2(x) : y = x + 10;
+  final int y;
+}''');
+    Map<String, DartObjectImpl> aFields =
+        _assertType(_evaluateTopLevelVariable(compilationUnit, "foo"), "A");
+    _assertIntField(aFields, 'y', 111);
+  }
+
+  void test_instanceCreationExpression_nonFactoryRedirect_cycle() {
+    // It is an error to have a cycle in non-factory redirects; however, we
+    // need to make sure that even if the error occurs, attempting to evaluate
+    // the constant will terminate.
+    CompilationUnit compilationUnit = resolveSource(r'''
+const foo = const A();
+class A {
+  const A() : this.b();
+  const A.b() : this();
+}''');
+    _assertValidUnknown(_evaluateTopLevelVariable(compilationUnit, "foo"));
+  }
+
+  void test_instanceCreationExpression_nonFactoryRedirect_defaultArg() {
+    CompilationUnit compilationUnit = resolveSource(r'''
+const foo = const A.a1();
+class A {
+  const A.a1() : this.a2();
+  const A.a2([x = 100]) : y = x + 10;
+  final int y;
+}''');
+    Map<String, DartObjectImpl> aFields =
+        _assertType(_evaluateTopLevelVariable(compilationUnit, "foo"), "A");
+    _assertIntField(aFields, 'y', 110);
+  }
+
+  void test_instanceCreationExpression_nonFactoryRedirect_toMissing() {
+    CompilationUnit compilationUnit = resolveSource(r'''
+const foo = const A.a1();
+class A {
+  const A.a1() : this.a2();
+}''');
+    // We don't care what value foo evaluates to (since there is a compile
+    // error), but we shouldn't crash, and we should figure
+    // out that it evaluates to an instance of class A.
+    _assertType(_evaluateTopLevelVariable(compilationUnit, "foo"), "A");
+  }
+
+  void test_instanceCreationExpression_nonFactoryRedirect_toNonConst() {
+    CompilationUnit compilationUnit = resolveSource(r'''
+const foo = const A.a1();
+class A {
+  const A.a1() : this.a2();
+  A.a2();
+}''');
+    // We don't care what value foo evaluates to (since there is a compile
+    // error), but we shouldn't crash, and we should figure
+    // out that it evaluates to an instance of class A.
+    _assertType(_evaluateTopLevelVariable(compilationUnit, "foo"), "A");
+  }
+
+  void test_instanceCreationExpression_nonFactoryRedirect_unnamed() {
+    CompilationUnit compilationUnit = resolveSource(r'''
+const foo = const A.a1();
+class A {
+  const A.a1() : this();
+  const A() : x = 5;
+  final int x;
+}''');
+    Map<String, DartObjectImpl> aFields =
+        _assertType(_evaluateTopLevelVariable(compilationUnit, "foo"), "A");
+    _assertIntField(aFields, 'x', 5);
+  }
+
+  void test_instanceCreationExpression_redirect() {
+    CompilationUnit compilationUnit = resolveSource(r'''
+const foo = const A();
+class A {
+  const factory A() = B;
+}
+class B implements A {
+  const B();
+}''');
+    _assertType(_evaluateTopLevelVariable(compilationUnit, "foo"), "B");
+  }
+
+  void test_instanceCreationExpression_redirect_cycle() {
+    // It is an error to have a cycle in factory redirects; however, we need
+    // to make sure that even if the error occurs, attempting to evaluate the
+    // constant will terminate.
+    CompilationUnit compilationUnit = resolveSource(r'''
+const foo = const A();
+class A {
+  const factory A() = A.b;
+  const factory A.b() = A;
+}''');
+    _assertValidUnknown(_evaluateTopLevelVariable(compilationUnit, "foo"));
+  }
+
+  void test_instanceCreationExpression_redirect_external() {
+    CompilationUnit compilationUnit = resolveSource(r'''
+const foo = const A();
+class A {
+  external const factory A();
+}''');
+    _assertValidUnknown(_evaluateTopLevelVariable(compilationUnit, "foo"));
+  }
+
+  void test_instanceCreationExpression_redirect_nonConst() {
+    // It is an error for a const factory constructor redirect to a non-const
+    // constructor; however, we need to make sure that even if the error
+    // attempting to evaluate the constant won't cause a crash.
+    CompilationUnit compilationUnit = resolveSource(r'''
+const foo = const A();
+class A {
+  const factory A() = A.b;
+  A.b();
+}''');
+    _assertValidUnknown(_evaluateTopLevelVariable(compilationUnit, "foo"));
+  }
+
+  void test_instanceCreationExpression_redirectWithTypeParams() {
+    CompilationUnit compilationUnit = resolveSource(r'''
+class A {
+  const factory A(var a) = B<int>;
+}
+
+class B<T> implements A {
+  final T x;
+  const B(this.x);
+}
+
+const A a = const A(10);''');
+    EvaluationResultImpl result =
+        _evaluateTopLevelVariable(compilationUnit, "a");
+    Map<String, DartObjectImpl> fields = _assertType(result, "B<int>");
+    expect(fields, hasLength(1));
+    _assertIntField(fields, "x", 10);
+  }
+
+  void test_instanceCreationExpression_redirectWithTypeSubstitution() {
+    // To evaluate the redirection of A<int>,
+    // A's template argument (T=int) must be substituted
+    // into B's template argument (B<U> where U=T) to get B<int>.
+    CompilationUnit compilationUnit = resolveSource(r'''
+class A<T> {
+  const factory A(var a) = B<T>;
+}
+
+class B<U> implements A {
+  final U x;
+  const B(this.x);
+}
+
+const A<int> a = const A<int>(10);''');
+    EvaluationResultImpl result =
+        _evaluateTopLevelVariable(compilationUnit, "a");
+    Map<String, DartObjectImpl> fields = _assertType(result, "B<int>");
+    expect(fields, hasLength(1));
+    _assertIntField(fields, "x", 10);
+  }
+
+  void test_instanceCreationExpression_symbol() {
+    CompilationUnit compilationUnit =
+        resolveSource("const foo = const Symbol('a');");
+    EvaluationResultImpl evaluationResult =
+        _evaluateTopLevelVariable(compilationUnit, "foo");
+    expect(evaluationResult.value, isNotNull);
+    DartObjectImpl value = evaluationResult.value;
+    expect(value.type, typeProvider.symbolType);
+    expect(value.toSymbolValue(), "a");
+  }
+
+  void test_instanceCreationExpression_withSupertypeParams_explicit() {
+    _checkInstanceCreation_withSupertypeParams(true);
+  }
+
+  void test_instanceCreationExpression_withSupertypeParams_implicit() {
+    _checkInstanceCreation_withSupertypeParams(false);
+  }
+
+  void test_instanceCreationExpression_withTypeParams() {
+    CompilationUnit compilationUnit = resolveSource(r'''
+class C<E> {
+  const C();
+}
+const c_int = const C<int>();
+const c_num = const C<num>();''');
+    EvaluationResultImpl c_int =
+        _evaluateTopLevelVariable(compilationUnit, "c_int");
+    _assertType(c_int, "C<int>");
+    DartObjectImpl c_int_value = c_int.value;
+    EvaluationResultImpl c_num =
+        _evaluateTopLevelVariable(compilationUnit, "c_num");
+    _assertType(c_num, "C<num>");
+    DartObjectImpl c_num_value = c_num.value;
+    expect(c_int_value == c_num_value, isFalse);
+  }
+
+  void test_isValidSymbol() {
+    expect(ConstantEvaluationEngine.isValidPublicSymbol(""), isTrue);
+    expect(ConstantEvaluationEngine.isValidPublicSymbol("foo"), isTrue);
+    expect(ConstantEvaluationEngine.isValidPublicSymbol("foo.bar"), isTrue);
+    expect(ConstantEvaluationEngine.isValidPublicSymbol("foo\$"), isTrue);
+    expect(ConstantEvaluationEngine.isValidPublicSymbol("foo\$bar"), isTrue);
+    expect(ConstantEvaluationEngine.isValidPublicSymbol("iff"), isTrue);
+    expect(ConstantEvaluationEngine.isValidPublicSymbol("gif"), isTrue);
+    expect(ConstantEvaluationEngine.isValidPublicSymbol("if\$"), isTrue);
+    expect(ConstantEvaluationEngine.isValidPublicSymbol("\$if"), isTrue);
+    expect(ConstantEvaluationEngine.isValidPublicSymbol("foo="), isTrue);
+    expect(ConstantEvaluationEngine.isValidPublicSymbol("foo.bar="), isTrue);
+    expect(ConstantEvaluationEngine.isValidPublicSymbol("foo.+"), isTrue);
+    expect(ConstantEvaluationEngine.isValidPublicSymbol("void"), isTrue);
+    expect(ConstantEvaluationEngine.isValidPublicSymbol("_foo"), isFalse);
+    expect(ConstantEvaluationEngine.isValidPublicSymbol("_foo.bar"), isFalse);
+    expect(ConstantEvaluationEngine.isValidPublicSymbol("foo._bar"), isFalse);
+    expect(ConstantEvaluationEngine.isValidPublicSymbol("if"), isFalse);
+    expect(ConstantEvaluationEngine.isValidPublicSymbol("if.foo"), isFalse);
+    expect(ConstantEvaluationEngine.isValidPublicSymbol("foo.if"), isFalse);
+    expect(ConstantEvaluationEngine.isValidPublicSymbol("foo=.bar"), isFalse);
+    expect(ConstantEvaluationEngine.isValidPublicSymbol("foo."), isFalse);
+    expect(ConstantEvaluationEngine.isValidPublicSymbol("+.foo"), isFalse);
+    expect(ConstantEvaluationEngine.isValidPublicSymbol("void.foo"), isFalse);
+    expect(ConstantEvaluationEngine.isValidPublicSymbol("foo.void"), isFalse);
+  }
+
+  void test_length_of_improperly_typed_string_expression() {
+    // Since type annotations are ignored in unchecked mode, the improper
+    // types on s1 and s2 shouldn't prevent us from evaluating i to
+    // 'alpha'.length.
+    CompilationUnit compilationUnit = resolveSource('''
+const int s1 = 'alpha';
+const int s2 = 'beta';
+const int i = (true ? s1 : s2).length;
+''');
+    ConstTopLevelVariableElementImpl element =
+        findTopLevelDeclaration(compilationUnit, 'i').element;
+    EvaluationResultImpl result = element.evaluationResult;
+    expect(_assertValidInt(result), 5);
+  }
+
+  void test_length_of_improperly_typed_string_identifier() {
+    // Since type annotations are ignored in unchecked mode, the improper type
+    // on s shouldn't prevent us from evaluating i to 'alpha'.length.
+    CompilationUnit compilationUnit = resolveSource('''
+const int s = 'alpha';
+const int i = s.length;
+''');
+    ConstTopLevelVariableElementImpl element =
+        findTopLevelDeclaration(compilationUnit, 'i').element;
+    EvaluationResultImpl result = element.evaluationResult;
+    expect(_assertValidInt(result), 5);
+  }
+
+  void test_non_static_const_initialized_at_declaration() {
+    // Even though non-static consts are not allowed by the language, we need
+    // to handle them for error recovery purposes.
+    CompilationUnit compilationUnit = resolveSource('''
+class A {
+  const int i = 123;
+  const A();
+}
+
+const A a = const A();
+''');
+    EvaluationResultImpl result =
+        _evaluateTopLevelVariable(compilationUnit, 'a');
+    Map<String, DartObjectImpl> fields = _assertType(result, "A");
+    expect(fields, hasLength(1));
+    _assertIntField(fields, "i", 123);
+  }
+
+  void test_symbolLiteral_void() {
+    CompilationUnit compilationUnit =
+        resolveSource("const voidSymbol = #void;");
+    VariableDeclaration voidSymbol =
+        findTopLevelDeclaration(compilationUnit, "voidSymbol");
+    EvaluationResultImpl voidSymbolResult =
+        (voidSymbol.element as VariableElementImpl).evaluationResult;
+    DartObjectImpl value = voidSymbolResult.value;
+    expect(value.type, typeProvider.symbolType);
+    expect(value.toSymbolValue(), "void");
+  }
+
+  Map<String, DartObjectImpl> _assertFieldType(
+      Map<String, DartObjectImpl> fields,
+      String fieldName,
+      String expectedType) {
+    DartObjectImpl field = fields[fieldName];
+    expect(field.type.displayName, expectedType);
+    return field.fields;
+  }
+
+  void _assertIntField(
+      Map<String, DartObjectImpl> fields, String fieldName, int expectedValue) {
+    DartObjectImpl field = fields[fieldName];
+    expect(field.type.name, "int");
+    expect(field.toIntValue(), expectedValue);
+  }
+
+  void _assertNullField(Map<String, DartObjectImpl> fields, String fieldName) {
+    DartObjectImpl field = fields[fieldName];
+    expect(field.isNull, isTrue);
+  }
+
+  void _assertProperDependencies(String sourceText,
+      [List<ErrorCode> expectedErrorCodes = ErrorCode.EMPTY_LIST]) {
+    Source source = addSource(sourceText);
+    LibraryElement element = resolve2(source);
+    CompilationUnit unit =
+        analysisContext.resolveCompilationUnit(source, element);
+    expect(unit, isNotNull);
+    ConstantValueComputer computer = _makeConstantValueComputer();
+    computer.add(unit, source, source);
+    computer.computeValues();
+    assertErrors(source, expectedErrorCodes);
+  }
+
+  Map<String, DartObjectImpl> _assertType(
+      EvaluationResultImpl result, String typeName) {
+    expect(result.value, isNotNull);
+    DartObjectImpl value = result.value;
+    expect(value.type.displayName, typeName);
+    return value.fields;
+  }
+
+  bool _assertValidBool(EvaluationResultImpl result) {
+    expect(result.value, isNotNull);
+    DartObjectImpl value = result.value;
+    expect(value.type, typeProvider.boolType);
+    bool boolValue = value.toBoolValue();
+    expect(boolValue, isNotNull);
+    return boolValue;
+  }
+
+  int _assertValidInt(EvaluationResultImpl result) {
+    expect(result, isNotNull);
+    expect(result.value, isNotNull);
+    DartObjectImpl value = result.value;
+    expect(value.type, typeProvider.intType);
+    return value.toIntValue();
+  }
+
+  void _assertValidNull(EvaluationResultImpl result) {
+    expect(result.value, isNotNull);
+    DartObjectImpl value = result.value;
+    expect(value.type, typeProvider.nullType);
+  }
+
+  String _assertValidString(EvaluationResultImpl result) {
+    expect(result.value, isNotNull);
+    DartObjectImpl value = result.value;
+    expect(value.type, typeProvider.stringType);
+    return value.toStringValue();
+  }
+
+  void _assertValidUnknown(EvaluationResultImpl result) {
+    expect(result.value, isNotNull);
+    DartObjectImpl value = result.value;
+    expect(value.isUnknown, isTrue);
+  }
+
+  EvaluationResultImpl _check_fromEnvironment_bool(
+      String valueInEnvironment, String defaultExpr) {
+    String envVarName = "x";
+    String varName = "foo";
+    if (valueInEnvironment != null) {
+      analysisContext2.declaredVariables.define(envVarName, valueInEnvironment);
+    }
+    String defaultArg =
+        defaultExpr == null ? "" : ", defaultValue: $defaultExpr";
+    CompilationUnit compilationUnit = resolveSource(
+        "const $varName = const bool.fromEnvironment('$envVarName'$defaultArg);");
+    return _evaluateTopLevelVariable(compilationUnit, varName);
+  }
+
+  EvaluationResultImpl _check_fromEnvironment_int(
+      String valueInEnvironment, String defaultExpr) {
+    String envVarName = "x";
+    String varName = "foo";
+    if (valueInEnvironment != null) {
+      analysisContext2.declaredVariables.define(envVarName, valueInEnvironment);
+    }
+    String defaultArg =
+        defaultExpr == null ? "" : ", defaultValue: $defaultExpr";
+    CompilationUnit compilationUnit = resolveSource(
+        "const $varName = const int.fromEnvironment('$envVarName'$defaultArg);");
+    return _evaluateTopLevelVariable(compilationUnit, varName);
+  }
+
+  EvaluationResultImpl _check_fromEnvironment_string(
+      String valueInEnvironment, String defaultExpr) {
+    String envVarName = "x";
+    String varName = "foo";
+    if (valueInEnvironment != null) {
+      analysisContext2.declaredVariables.define(envVarName, valueInEnvironment);
+    }
+    String defaultArg =
+        defaultExpr == null ? "" : ", defaultValue: $defaultExpr";
+    CompilationUnit compilationUnit = resolveSource(
+        "const $varName = const String.fromEnvironment('$envVarName'$defaultArg);");
+    return _evaluateTopLevelVariable(compilationUnit, varName);
+  }
+
+  void _checkInstanceCreation_withSupertypeParams(bool isExplicit) {
+    String superCall = isExplicit ? " : super()" : "";
+    CompilationUnit compilationUnit = resolveSource("""
+class A<T> {
+  const A();
+}
+class B<T, U> extends A<T> {
+  const B()$superCall;
+}
+class C<T, U> extends A<U> {
+  const C()$superCall;
+}
+const b_int_num = const B<int, num>();
+const c_int_num = const C<int, num>();""");
+    EvaluationResultImpl b_int_num =
+        _evaluateTopLevelVariable(compilationUnit, "b_int_num");
+    Map<String, DartObjectImpl> b_int_num_fields =
+        _assertType(b_int_num, "B<int, num>");
+    _assertFieldType(b_int_num_fields, GenericState.SUPERCLASS_FIELD, "A<int>");
+    EvaluationResultImpl c_int_num =
+        _evaluateTopLevelVariable(compilationUnit, "c_int_num");
+    Map<String, DartObjectImpl> c_int_num_fields =
+        _assertType(c_int_num, "C<int, num>");
+    _assertFieldType(c_int_num_fields, GenericState.SUPERCLASS_FIELD, "A<num>");
+  }
+
+  void _checkInstanceCreationOptionalParams(
+      bool isFieldFormal, bool isNamed, bool hasDefault) {
+    String fieldName = "j";
+    String paramName = isFieldFormal ? fieldName : "i";
+    String formalParam =
+        "${isFieldFormal ? "this." : "int "}$paramName${hasDefault ? " = 3" : ""}";
+    CompilationUnit compilationUnit = resolveSource("""
+const x = const A();
+const y = const A(${isNamed ? '$paramName: ' : ''}10);
+class A {
+  const A(${isNamed ? "{$formalParam}" : "[$formalParam]"})${isFieldFormal ? "" : " : $fieldName = $paramName"};
+  final int $fieldName;
+}""");
+    EvaluationResultImpl x = _evaluateTopLevelVariable(compilationUnit, "x");
+    Map<String, DartObjectImpl> fieldsOfX = _assertType(x, "A");
+    expect(fieldsOfX, hasLength(1));
+    if (hasDefault) {
+      _assertIntField(fieldsOfX, fieldName, 3);
+    } else {
+      _assertNullField(fieldsOfX, fieldName);
+    }
+    EvaluationResultImpl y = _evaluateTopLevelVariable(compilationUnit, "y");
+    Map<String, DartObjectImpl> fieldsOfY = _assertType(y, "A");
+    expect(fieldsOfY, hasLength(1));
+    _assertIntField(fieldsOfY, fieldName, 10);
+  }
+
+  /**
+   * Search [compilationUnit] for a class named [className], containing a
+   * method [methodName], with exactly one annotation.  Return the constant
+   * value of the annotation.
+   */
+  EvaluationResultImpl _evaluateAnnotation(
+      CompilationUnit compilationUnit, String className, String memberName) {
+    for (CompilationUnitMember member in compilationUnit.declarations) {
+      if (member is ClassDeclaration && member.name.name == className) {
+        for (ClassMember classMember in member.members) {
+          if (classMember is MethodDeclaration &&
+              classMember.name.name == memberName) {
+            expect(classMember.metadata, hasLength(1));
+            ElementAnnotationImpl elementAnnotation =
+                classMember.metadata[0].elementAnnotation;
+            return elementAnnotation.evaluationResult;
+          }
+        }
+      }
+    }
+    fail('Class member not found');
+    return null;
+  }
+
+  EvaluationResultImpl _evaluateTopLevelVariable(
+      CompilationUnit compilationUnit, String name) {
+    VariableDeclaration varDecl =
+        findTopLevelDeclaration(compilationUnit, name);
+    ConstTopLevelVariableElementImpl varElement = varDecl.element;
+    return varElement.evaluationResult;
+  }
+
+  ConstantValueComputer _makeConstantValueComputer() {
+    ConstantEvaluationValidator_ForTest validator =
+        new ConstantEvaluationValidator_ForTest(analysisContext2);
+    validator.computer = new ConstantValueComputer(
+        analysisContext2,
+        analysisContext2.typeProvider,
+        analysisContext2.declaredVariables,
+        validator,
+        analysisContext2.typeSystem);
+    return validator.computer;
+  }
+
+  void _validate(bool shouldBeValid, VariableDeclarationList declarationList) {
+    for (VariableDeclaration declaration in declarationList.variables) {
+      VariableElementImpl element = declaration.element as VariableElementImpl;
+      expect(element, isNotNull);
+      EvaluationResultImpl result = element.evaluationResult;
+      if (shouldBeValid) {
+        expect(result.value, isNotNull);
+      } else {
+        expect(result.value, isNull);
+      }
+    }
+  }
+}
+
+@reflectiveTest
+class ConstantVisitorTest extends ResolverTestCase {
+  void test_visitBinaryExpression_questionQuestion_notNull_notNull() {
+    Expression left = AstFactory.string2('a');
+    Expression right = AstFactory.string2('b');
+    Expression expression =
+        AstFactory.binaryExpression(left, TokenType.QUESTION_QUESTION, right);
+
+    GatheringErrorListener errorListener = new GatheringErrorListener();
+    ErrorReporter errorReporter =
+        new ErrorReporter(errorListener, _dummySource());
+    DartObjectImpl result = _evaluate(expression, errorReporter);
+    expect(result, isNotNull);
+    expect(result.isNull, isFalse);
+    expect(result.toStringValue(), 'a');
+    errorListener.assertNoErrors();
+  }
+
+  void test_visitBinaryExpression_questionQuestion_null_notNull() {
+    Expression left = AstFactory.nullLiteral();
+    Expression right = AstFactory.string2('b');
+    Expression expression =
+        AstFactory.binaryExpression(left, TokenType.QUESTION_QUESTION, right);
+
+    GatheringErrorListener errorListener = new GatheringErrorListener();
+    ErrorReporter errorReporter =
+        new ErrorReporter(errorListener, _dummySource());
+    DartObjectImpl result = _evaluate(expression, errorReporter);
+    expect(result, isNotNull);
+    expect(result.isNull, isFalse);
+    expect(result.toStringValue(), 'b');
+    errorListener.assertNoErrors();
+  }
+
+  void test_visitBinaryExpression_questionQuestion_null_null() {
+    Expression left = AstFactory.nullLiteral();
+    Expression right = AstFactory.nullLiteral();
+    Expression expression =
+        AstFactory.binaryExpression(left, TokenType.QUESTION_QUESTION, right);
+
+    GatheringErrorListener errorListener = new GatheringErrorListener();
+    ErrorReporter errorReporter =
+        new ErrorReporter(errorListener, _dummySource());
+    DartObjectImpl result = _evaluate(expression, errorReporter);
+    expect(result, isNotNull);
+    expect(result.isNull, isTrue);
+    errorListener.assertNoErrors();
+  }
+
+  void test_visitConditionalExpression_false() {
+    Expression thenExpression = AstFactory.integer(1);
+    Expression elseExpression = AstFactory.integer(0);
+    ConditionalExpression expression = AstFactory.conditionalExpression(
+        AstFactory.booleanLiteral(false), thenExpression, elseExpression);
+    GatheringErrorListener errorListener = new GatheringErrorListener();
+    ErrorReporter errorReporter =
+        new ErrorReporter(errorListener, _dummySource());
+    _assertValue(0, _evaluate(expression, errorReporter));
+    errorListener.assertNoErrors();
+  }
+
+  void test_visitConditionalExpression_nonBooleanCondition() {
+    Expression thenExpression = AstFactory.integer(1);
+    Expression elseExpression = AstFactory.integer(0);
+    NullLiteral conditionExpression = AstFactory.nullLiteral();
+    ConditionalExpression expression = AstFactory.conditionalExpression(
+        conditionExpression, thenExpression, elseExpression);
+    GatheringErrorListener errorListener = new GatheringErrorListener();
+    ErrorReporter errorReporter =
+        new ErrorReporter(errorListener, _dummySource());
+    DartObjectImpl result = _evaluate(expression, errorReporter);
+    expect(result, isNull);
+    errorListener
+        .assertErrorsWithCodes([CompileTimeErrorCode.CONST_EVAL_TYPE_BOOL]);
+  }
+
+  void test_visitConditionalExpression_nonConstantElse() {
+    Expression thenExpression = AstFactory.integer(1);
+    Expression elseExpression = AstFactory.identifier3("x");
+    ConditionalExpression expression = AstFactory.conditionalExpression(
+        AstFactory.booleanLiteral(true), thenExpression, elseExpression);
+    GatheringErrorListener errorListener = new GatheringErrorListener();
+    ErrorReporter errorReporter =
+        new ErrorReporter(errorListener, _dummySource());
+    DartObjectImpl result = _evaluate(expression, errorReporter);
+    expect(result, isNull);
+    errorListener
+        .assertErrorsWithCodes([CompileTimeErrorCode.INVALID_CONSTANT]);
+  }
+
+  void test_visitConditionalExpression_nonConstantThen() {
+    Expression thenExpression = AstFactory.identifier3("x");
+    Expression elseExpression = AstFactory.integer(0);
+    ConditionalExpression expression = AstFactory.conditionalExpression(
+        AstFactory.booleanLiteral(true), thenExpression, elseExpression);
+    GatheringErrorListener errorListener = new GatheringErrorListener();
+    ErrorReporter errorReporter =
+        new ErrorReporter(errorListener, _dummySource());
+    DartObjectImpl result = _evaluate(expression, errorReporter);
+    expect(result, isNull);
+    errorListener
+        .assertErrorsWithCodes([CompileTimeErrorCode.INVALID_CONSTANT]);
+  }
+
+  void test_visitConditionalExpression_true() {
+    Expression thenExpression = AstFactory.integer(1);
+    Expression elseExpression = AstFactory.integer(0);
+    ConditionalExpression expression = AstFactory.conditionalExpression(
+        AstFactory.booleanLiteral(true), thenExpression, elseExpression);
+    GatheringErrorListener errorListener = new GatheringErrorListener();
+    ErrorReporter errorReporter =
+        new ErrorReporter(errorListener, _dummySource());
+    _assertValue(1, _evaluate(expression, errorReporter));
+    errorListener.assertNoErrors();
+  }
+
+  void test_visitSimpleIdentifier_className() {
+    CompilationUnit compilationUnit = resolveSource('''
+const a = C;
+class C {}
+''');
+    DartObjectImpl result = _evaluateConstant(compilationUnit, 'a', null);
+    expect(result.type, typeProvider.typeType);
+    expect(result.toTypeValue().name, 'C');
+  }
+
+  void test_visitSimpleIdentifier_dynamic() {
+    CompilationUnit compilationUnit = resolveSource('''
+const a = dynamic;
+''');
+    DartObjectImpl result = _evaluateConstant(compilationUnit, 'a', null);
+    expect(result.type, typeProvider.typeType);
+    expect(result.toTypeValue(), typeProvider.dynamicType);
+  }
+
+  void test_visitSimpleIdentifier_inEnvironment() {
+    CompilationUnit compilationUnit = resolveSource(r'''
+const a = b;
+const b = 3;''');
+    Map<String, DartObjectImpl> environment = new Map<String, DartObjectImpl>();
+    DartObjectImpl six =
+        new DartObjectImpl(typeProvider.intType, new IntState(6));
+    environment["b"] = six;
+    _assertValue(6, _evaluateConstant(compilationUnit, "a", environment));
+  }
+
+  void test_visitSimpleIdentifier_notInEnvironment() {
+    CompilationUnit compilationUnit = resolveSource(r'''
+const a = b;
+const b = 3;''');
+    Map<String, DartObjectImpl> environment = new Map<String, DartObjectImpl>();
+    DartObjectImpl six =
+        new DartObjectImpl(typeProvider.intType, new IntState(6));
+    environment["c"] = six;
+    _assertValue(3, _evaluateConstant(compilationUnit, "a", environment));
+  }
+
+  void test_visitSimpleIdentifier_withoutEnvironment() {
+    CompilationUnit compilationUnit = resolveSource(r'''
+const a = b;
+const b = 3;''');
+    _assertValue(3, _evaluateConstant(compilationUnit, "a", null));
+  }
+
+  void _assertValue(int expectedValue, DartObjectImpl result) {
+    expect(result, isNotNull);
+    expect(result.type.name, "int");
+    expect(result.toIntValue(), expectedValue);
+  }
+
+  NonExistingSource _dummySource() {
+    String path = '/test.dart';
+    return new NonExistingSource(path, toUri(path), UriKind.FILE_URI);
+  }
+
+  DartObjectImpl _evaluate(Expression expression, ErrorReporter errorReporter) {
+    return expression.accept(new ConstantVisitor(
+        new ConstantEvaluationEngine(
+            new TestTypeProvider(), new DeclaredVariables(),
+            typeSystem: new TypeSystemImpl()),
+        errorReporter));
+  }
+
+  DartObjectImpl _evaluateConstant(CompilationUnit compilationUnit, String name,
+      Map<String, DartObjectImpl> lexicalEnvironment) {
+    Source source = compilationUnit.element.source;
+    Expression expression =
+        findTopLevelConstantExpression(compilationUnit, name);
+    GatheringErrorListener errorListener = new GatheringErrorListener();
+    ErrorReporter errorReporter = new ErrorReporter(errorListener, source);
+    DartObjectImpl result = expression.accept(new ConstantVisitor(
+        new ConstantEvaluationEngine(typeProvider, new DeclaredVariables(),
+            typeSystem: typeSystem),
+        errorReporter,
+        lexicalEnvironment: lexicalEnvironment));
+    errorListener.assertNoErrors();
+    return result;
+  }
+}