Split KernelToElementMap mixins to match interfaces

pkg/compiler/lib/src/kernel/element_map.dart

Index: pkg/compiler/lib/src/kernel/element_map.dart
diff --git a/pkg/compiler/lib/src/kernel/element_map.dart b/pkg/compiler/lib/src/kernel/element_map.dart
index 6dcff310c781af918b18ba09432f2e945b255aaf..3b701de96d4bb9b9baa1efa0557106ec2b8627e1 100644
--- a/pkg/compiler/lib/src/kernel/element_map.dart
+++ b/pkg/compiler/lib/src/kernel/element_map.dart
@@ -2,23 +2,17 @@
 // 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.
 
-import 'package:js_runtime/shared/embedded_names.dart';
 import 'package:kernel/ast.dart' as ir;
 
 import '../closure.dart';
 import '../common.dart';
-import '../common/names.dart';
-import '../constants/constructors.dart';
-import '../constants/expressions.dart';
 import '../constants/values.dart';
 import '../common_elements.dart';
 import '../elements/entities.dart';
 import '../elements/jumps.dart';
 import '../elements/names.dart';
-import '../elements/operators.dart';
 import '../elements/types.dart';
 import '../js/js.dart' as js;
-import '../js_backend/backend.dart' show JavaScriptBackend;
 import '../js_backend/namer.dart';
 import '../js_emitter/code_emitter_task.dart';
 import '../native/native.dart' as native;
@@ -26,7 +20,6 @@ import '../types/types.dart';
 import '../universe/call_structure.dart';
 import '../universe/selector.dart';
 import '../world.dart';
-import 'kernel_debug.dart';
 
 /// Interface that translates between Kernel IR nodes and entities.
 abstract class KernelToElementMap {
@@ -36,11 +29,20 @@ abstract class KernelToElementMap {
   /// Returns the [DartType] corresponding to [type].
   DartType getDartType(ir.DartType type);
 
+  /// Returns the [InterfaceType] corresponding to [type].
+  InterfaceType getInterfaceType(ir.InterfaceType type);
+
+  /// Returns the [FunctionType] of the [node].
+  FunctionType getFunctionType(ir.FunctionNode node);
+
   /// Return the [InterfaceType] corresponding to the [cls] with the given
   /// [typeArguments].
   InterfaceType createInterfaceType(
       ir.Class cls, List<ir.DartType> typeArguments);
 
+  /// Returns the [CallStructure] corresponding to the [arguments].
+  CallStructure getCallStructure(ir.Arguments arguments);
+
   /// Returns the [Selector] corresponding to the invocation or getter/setter
   /// access of [node].
   Selector getSelector(ir.Expression node);
@@ -58,6 +60,9 @@ abstract class KernelToElementMap {
   /// Returns the [FieldEntity] corresponding to the field [node].
   FieldEntity getField(ir.Field node);
 
+  /// Returns the [ClassEntity] corresponding to the class [node].
+  ClassEntity getClass(ir.Class node);
+
   /// Returns the [Local] corresponding to the [node]. The node must be either
   /// a [ir.FunctionDeclaration] or [ir.FunctionExpression].
   Local getLocalFunction(ir.TreeNode node);
@@ -103,9 +108,6 @@ abstract class KernelToElementMap {
 /// Interface that translates between Kernel IR nodes and entities used for
 /// computing the [WorldImpact] for members.
 abstract class KernelToElementMapForImpact extends KernelToElementMap {
-  /// Returns the [CallStructure] corresponding to the [arguments].
-  CallStructure getCallStructure(ir.Arguments arguments);
-
   /// Returns the [ConstructorEntity] corresponding to a super initializer in
   /// [constructor].
   ///
@@ -153,21 +155,12 @@ abstract class KernelToElementMapForBuilding implements KernelToElementMap {
   /// [ElementEnvironment] for library, class and member lookup.
   ElementEnvironment get elementEnvironment;
 
-  /// Returns the [FunctionType] of the [node].
-  FunctionType getFunctionType(ir.FunctionNode node);
-
   /// Returns the list of [DartType]s corresponding to [types].
   List<DartType> getDartTypes(List<ir.DartType> types);
 
-  /// Returns the [InterfaceType] corresponding to [type].
-  InterfaceType getInterfaceType(ir.InterfaceType type);
-
   /// Returns the kernel IR node that defines the [member].
   ir.Node getMemberNode(covariant MemberEntity member);
 
-  /// Returns the [ClassEntity] corresponding to the class [node].
-  ClassEntity getClass(ir.Class node);
-
   /// Returns the [LibraryEntity] corresponding to the library [node].
   LibraryEntity getLibrary(ir.Library node);
 
@@ -197,823 +190,6 @@ enum ForeignKind {
   NONE,
 }
 
-abstract class KernelToElementMapMixin
-    implements KernelToElementMapForBuilding {
-  DiagnosticReporter get reporter;
-  native.BehaviorBuilder get nativeBehaviorBuilder;
-  ConstantValue computeConstantValue(ConstantExpression constant,
-      {bool requireConstant: true});
-
-  @override
-  Name getName(ir.Name name) {
-    return new Name(
-        name.name, name.isPrivate ? getLibrary(name.library) : null);
-  }
-
-  CallStructure getCallStructure(ir.Arguments arguments) {
-    int argumentCount = arguments.positional.length + arguments.named.length;
-    List<String> namedArguments = arguments.named.map((e) => e.name).toList();
-    return new CallStructure(argumentCount, namedArguments);
-  }
-
-  @override
-  Selector getSelector(ir.Expression node) {
-    // TODO(efortuna): This is screaming for a common interface between
-    // PropertyGet and SuperPropertyGet (and same for *Get). Talk to kernel
-    // folks.
-    if (node is ir.PropertyGet) {
-      return getGetterSelector(node.name);
-    }
-    if (node is ir.SuperPropertyGet) {
-      return getGetterSelector(node.name);
-    }
-    if (node is ir.PropertySet) {
-      return getSetterSelector(node.name);
-    }
-    if (node is ir.SuperPropertySet) {
-      return getSetterSelector(node.name);
-    }
-    if (node is ir.InvocationExpression) {
-      return getInvocationSelector(node);
-    }
-    throw new SpannableAssertionFailure(
-        CURRENT_ELEMENT_SPANNABLE,
-        "Can only get the selector for a property get or an invocation: "
-        "${node}");
-  }
-
-  Selector getInvocationSelector(ir.InvocationExpression invocation) {
-    Name name = getName(invocation.name);
-    SelectorKind kind;
-    if (Selector.isOperatorName(name.text)) {
-      if (name == Names.INDEX_NAME || name == Names.INDEX_SET_NAME) {
-        kind = SelectorKind.INDEX;
-      } else {
-        kind = SelectorKind.OPERATOR;
-      }
-    } else {
-      kind = SelectorKind.CALL;
-    }
-
-    CallStructure callStructure = getCallStructure(invocation.arguments);
-    return new Selector(kind, name, callStructure);
-  }
-
-  Selector getGetterSelector(ir.Name irName) {
-    Name name = new Name(
-        irName.name, irName.isPrivate ? getLibrary(irName.library) : null);
-    return new Selector.getter(name);
-  }
-
-  Selector getSetterSelector(ir.Name irName) {
-    Name name = new Name(
-        irName.name, irName.isPrivate ? getLibrary(irName.library) : null);
-    return new Selector.setter(name);
-  }
-
-  ConstantValue getConstantValue(ir.Expression node,
-      {bool requireConstant: true, bool implicitNull: false}) {
-    ConstantExpression constant;
-    if (node == null) {
-      if (!implicitNull) {
-        throw new SpannableAssertionFailure(
-            CURRENT_ELEMENT_SPANNABLE, 'No expression for constant.');
-      }
-      constant = new NullConstantExpression();
-    } else {
-      constant =
-          new Constantifier(this, requireConstant: requireConstant).visit(node);
-    }
-    if (constant == null) {
-      if (requireConstant) {
-        throw new UnsupportedError(
-            'No constant for ${DebugPrinter.prettyPrint(node)}');
-      }
-      return null;
-    }
-    return computeConstantValue(constant, requireConstant: requireConstant);
-  }
-
-  /// Converts [annotations] into a list of [ConstantValue]s.
-  List<ConstantValue> getMetadata(List<ir.Expression> annotations) {
-    if (annotations.isEmpty) return const <ConstantValue>[];
-    List<ConstantValue> metadata = <ConstantValue>[];
-    annotations.forEach((ir.Expression node) {
-      metadata.add(getConstantValue(node));
-    });
-    return metadata;
-  }
-
-  /// Returns `true` is [node] has a `@Native(...)` annotation.
-  // TODO(johnniwinther): Cache this for later use.
-  bool isNativeClass(ir.Class node) {
-    for (ir.Expression annotation in node.annotations) {
-      if (annotation is ir.ConstructorInvocation) {
-        FunctionEntity target = getConstructor(annotation.target);
-        if (target.enclosingClass == commonElements.nativeAnnotationClass) {
-          return true;
-        }
-      }
-    }
-    return false;
-  }
-
-  /// Compute the kind of foreign helper function called by [node], if any.
-  ForeignKind getForeignKind(ir.StaticInvocation node) {
-    if (isForeignLibrary(node.target.enclosingLibrary)) {
-      switch (node.target.name.name) {
-        case JavaScriptBackend.JS:
-          return ForeignKind.JS;
-        case JavaScriptBackend.JS_BUILTIN:
-          return ForeignKind.JS_BUILTIN;
-        case JavaScriptBackend.JS_EMBEDDED_GLOBAL:
-          return ForeignKind.JS_EMBEDDED_GLOBAL;
-        case JavaScriptBackend.JS_INTERCEPTOR_CONSTANT:
-          return ForeignKind.JS_INTERCEPTOR_CONSTANT;
-      }
-    }
-    return ForeignKind.NONE;
-  }
-
-  /// Return `true` if [node] is the `dart:_foreign_helper` library.
-  bool isForeignLibrary(ir.Library node) {
-    return node.importUri == Uris.dart__foreign_helper;
-  }
-
-  /// Looks up [typeName] for use in the spec-string of a `JS` called.
-  // TODO(johnniwinther): Use this in [native.NativeBehavior] instead of calling
-  // the `ForeignResolver`.
-  // TODO(johnniwinther): Cache the result to avoid redundant lookups?
-  native.TypeLookup typeLookup({bool resolveAsRaw: true}) {
-    DartType lookup(String typeName, {bool required}) {
-      DartType findIn(Uri uri) {
-        LibraryEntity library = elementEnvironment.lookupLibrary(uri);
-        if (library != null) {
-          ClassEntity cls = elementEnvironment.lookupClass(library, typeName);
-          if (cls != null) {
-            // TODO(johnniwinther): Align semantics.
-            return resolveAsRaw
-                ? elementEnvironment.getRawType(cls)
-                : elementEnvironment.getThisType(cls);
-          }
-        }
-        return null;
-      }
-
-      // TODO(johnniwinther): Narrow the set of lookups base on the depending
-      // library.
-      DartType type = findIn(Uris.dart_core);
-      type ??= findIn(Uris.dart__js_helper);
-      type ??= findIn(Uris.dart__interceptors);
-      type ??= findIn(Uris.dart__isolate_helper);
-      type ??= findIn(Uris.dart__native_typed_data);
-      type ??= findIn(Uris.dart_collection);
-      type ??= findIn(Uris.dart_math);
-      type ??= findIn(Uris.dart_html);
-      type ??= findIn(Uris.dart_html_common);
-      type ??= findIn(Uris.dart_svg);
-      type ??= findIn(Uris.dart_web_audio);
-      type ??= findIn(Uris.dart_web_gl);
-      type ??= findIn(Uris.dart_web_sql);
-      type ??= findIn(Uris.dart_indexed_db);
-      type ??= findIn(Uris.dart_typed_data);
-      if (type == null && required) {
-        reporter.reportErrorMessage(CURRENT_ELEMENT_SPANNABLE,
-            MessageKind.GENERIC, {'text': "Type '$typeName' not found."});
-      }
-      return type;
-    }
-
-    return lookup;
-  }
-
-  String _getStringArgument(ir.StaticInvocation node, int index) {
-    return node.arguments.positional[index].accept(new Stringifier());
-  }
-
-  /// Computes the [native.NativeBehavior] for a call to the [JS] function.
-  // TODO(johnniwinther): Cache this for later use.
-  native.NativeBehavior getNativeBehaviorForJsCall(ir.StaticInvocation node) {
-    if (node.arguments.positional.length < 2 ||
-        node.arguments.named.isNotEmpty) {
-      reporter.reportErrorMessage(
-          CURRENT_ELEMENT_SPANNABLE, MessageKind.WRONG_ARGUMENT_FOR_JS);
-      return new native.NativeBehavior();
-    }
-    String specString = _getStringArgument(node, 0);
-    if (specString == null) {
-      reporter.reportErrorMessage(
-          CURRENT_ELEMENT_SPANNABLE, MessageKind.WRONG_ARGUMENT_FOR_JS_FIRST);
-      return new native.NativeBehavior();
-    }
-
-    String codeString = _getStringArgument(node, 1);
-    if (codeString == null) {
-      reporter.reportErrorMessage(
-          CURRENT_ELEMENT_SPANNABLE, MessageKind.WRONG_ARGUMENT_FOR_JS_SECOND);
-      return new native.NativeBehavior();
-    }
-
-    return native.NativeBehavior.ofJsCall(
-        specString,
-        codeString,
-        typeLookup(resolveAsRaw: true),
-        CURRENT_ELEMENT_SPANNABLE,
-        reporter,
-        commonElements);
-  }
-
-  /// Computes the [native.NativeBehavior] for a call to the [JS_BUILTIN]
-  /// function.
-  // TODO(johnniwinther): Cache this for later use.
-  native.NativeBehavior getNativeBehaviorForJsBuiltinCall(
-      ir.StaticInvocation node) {
-    if (node.arguments.positional.length < 1) {
-      reporter.internalError(
-          CURRENT_ELEMENT_SPANNABLE, "JS builtin expression has no type.");
-      return new native.NativeBehavior();
-    }
-    if (node.arguments.positional.length < 2) {
-      reporter.internalError(
-          CURRENT_ELEMENT_SPANNABLE, "JS builtin is missing name.");
-      return new native.NativeBehavior();
-    }
-    String specString = _getStringArgument(node, 0);
-    if (specString == null) {
-      reporter.internalError(
-          CURRENT_ELEMENT_SPANNABLE, "Unexpected first argument.");
-      return new native.NativeBehavior();
-    }
-    return native.NativeBehavior.ofJsBuiltinCall(
-        specString,
-        typeLookup(resolveAsRaw: true),
-        CURRENT_ELEMENT_SPANNABLE,
-        reporter,
-        commonElements);
-  }
-
-  /// Computes the [native.NativeBehavior] for a call to the
-  /// [JS_EMBEDDED_GLOBAL] function.
-  // TODO(johnniwinther): Cache this for later use.
-  native.NativeBehavior getNativeBehaviorForJsEmbeddedGlobalCall(
-      ir.StaticInvocation node) {
-    if (node.arguments.positional.length < 1) {
-      reporter.internalError(CURRENT_ELEMENT_SPANNABLE,
-          "JS embedded global expression has no type.");
-      return new native.NativeBehavior();
-    }
-    if (node.arguments.positional.length < 2) {
-      reporter.internalError(
-          CURRENT_ELEMENT_SPANNABLE, "JS embedded global is missing name.");
-      return new native.NativeBehavior();
-    }
-    if (node.arguments.positional.length > 2 ||
-        node.arguments.named.isNotEmpty) {
-      reporter.internalError(CURRENT_ELEMENT_SPANNABLE,
-          "JS embedded global has more than 2 arguments.");
-      return new native.NativeBehavior();
-    }
-    String specString = _getStringArgument(node, 0);
-    if (specString == null) {
-      reporter.internalError(
-          CURRENT_ELEMENT_SPANNABLE, "Unexpected first argument.");
-      return new native.NativeBehavior();
-    }
-    return native.NativeBehavior.ofJsEmbeddedGlobalCall(
-        specString,
-        typeLookup(resolveAsRaw: true),
-        CURRENT_ELEMENT_SPANNABLE,
-        reporter,
-        commonElements);
-  }
-
-  /// Computes the [InterfaceType] referenced by a call to the
-  /// [JS_INTERCEPTOR_CONSTANT] function, if any.
-  InterfaceType getInterfaceTypeForJsInterceptorCall(ir.StaticInvocation node) {
-    if (node.arguments.positional.length != 1 ||
-        node.arguments.named.isNotEmpty) {
-      reporter.reportErrorMessage(CURRENT_ELEMENT_SPANNABLE,
-          MessageKind.WRONG_ARGUMENT_FOR_JS_INTERCEPTOR_CONSTANT);
-    }
-    ir.Node argument = node.arguments.positional.first;
-    if (argument is ir.TypeLiteral && argument.type is ir.InterfaceType) {
-      return getInterfaceType(argument.type);
-    }
-    return null;
-  }
-
-  /// Computes the native behavior for reading the native [field].
-  // TODO(johnniwinther): Cache this for later use.
-  native.NativeBehavior getNativeBehaviorForFieldLoad(ir.Field field,
-      {bool isJsInterop}) {
-    DartType type = getDartType(field.type);
-    List<ConstantValue> metadata = getMetadata(field.annotations);
-    return nativeBehaviorBuilder.buildFieldLoadBehavior(
-        type, metadata, typeLookup(resolveAsRaw: false),
-        isJsInterop: isJsInterop);
-  }
-
-  /// Computes the native behavior for writing to the native [field].
-  // TODO(johnniwinther): Cache this for later use.
-  native.NativeBehavior getNativeBehaviorForFieldStore(ir.Field field) {
-    DartType type = getDartType(field.type);
-    return nativeBehaviorBuilder.buildFieldStoreBehavior(type);
-  }
-
-  /// Computes the native behavior for calling [procedure].
-  // TODO(johnniwinther): Cache this for later use.
-  native.NativeBehavior getNativeBehaviorForMethod(ir.Procedure procedure,
-      {bool isJsInterop}) {
-    DartType type = getFunctionType(procedure.function);
-    List<ConstantValue> metadata = getMetadata(procedure.annotations);
-    return nativeBehaviorBuilder.buildMethodBehavior(
-        type, metadata, typeLookup(resolveAsRaw: false),
-        isJsInterop: isJsInterop);
-  }
-
-  @override
-  FunctionEntity getSuperNoSuchMethod(ClassEntity cls) {
-    while (cls != null) {
-      cls = elementEnvironment.getSuperClass(cls);
-      MemberEntity member =
-          elementEnvironment.lookupClassMember(cls, Identifiers.noSuchMethod_);
-      if (member != null) {
-        if (member.isFunction) {
-          FunctionEntity function = member;
-          if (function.parameterStructure.positionalParameters >= 1) {
-            return function;
-          }
-        }
-        // If [member] is not a valid `noSuchMethod` the target is
-        // `Object.superNoSuchMethod`.
-        break;
-      }
-    }
-    FunctionEntity function = elementEnvironment.lookupClassMember(
-        commonElements.objectClass, Identifiers.noSuchMethod_);
-    assert(function != null,
-        failedAt(cls, "No super noSuchMethod found for class $cls."));
-    return function;
-  }
-
-  js.Name getNameForJsGetName(ConstantValue constant, Namer namer) {
-    int index = _extractEnumIndexFromConstantValue(
-        constant, commonElements.jsGetNameEnum);
-    if (index == null) return null;
-    return namer.getNameForJsGetName(
-        CURRENT_ELEMENT_SPANNABLE, JsGetName.values[index]);
-  }
-
-  js.Template getJsBuiltinTemplate(
-      ConstantValue constant, CodeEmitterTask emitter) {
-    int index = _extractEnumIndexFromConstantValue(
-        constant, commonElements.jsBuiltinEnum);
-    if (index == null) return null;
-    return emitter.builtinTemplateFor(JsBuiltin.values[index]);
-  }
-
-  int _extractEnumIndexFromConstantValue(
-      ConstantValue constant, ClassEntity classElement) {
-    if (constant is ConstructedConstantValue) {
-      if (constant.type.element == classElement) {
-        assert(constant.fields.length == 1 || constant.fields.length == 2);
-        ConstantValue indexConstant = constant.fields.values.first;
-        if (indexConstant is IntConstantValue) {
-          return indexConstant.primitiveValue;
-        }
-      }
-    }
-    return null;
-  }
-}
-
-/// Visitor that converts string literals and concatenations of string literals
-/// into the string value.
-class Stringifier extends ir.ExpressionVisitor<String> {
-  @override
-  String visitStringLiteral(ir.StringLiteral node) => node.value;
-
-  @override
-  String visitStringConcatenation(ir.StringConcatenation node) {
-    StringBuffer sb = new StringBuffer();
-    for (ir.Expression expression in node.expressions) {
-      String value = expression.accept(this);
-      if (value == null) return null;
-      sb.write(value);
-    }
-    return sb.toString();
-  }
-}
-
-/// Visitor that converts a kernel constant expression into a
-/// [ConstantExpression].
-class Constantifier extends ir.ExpressionVisitor<ConstantExpression> {
-  final bool requireConstant;
-  final KernelToElementMapMixin elementAdapter;
-
-  Constantifier(this.elementAdapter, {this.requireConstant: true});
-
-  CommonElements get _commonElements => elementAdapter.commonElements;
-
-  ConstantExpression visit(ir.Expression node) {
-    ConstantExpression constant = node.accept(this);
-    if (constant == null && requireConstant) {
-      throw new UnsupportedError(
-          "No constant computed for $node (${node.runtimeType})");
-    }
-    return constant;
-  }
-
-  ConstantExpression defaultExpression(ir.Expression node) {
-    if (requireConstant) {
-      throw new UnimplementedError(
-          'Unimplemented constant expression $node (${node.runtimeType})');
-    }
-    return null;
-  }
-
-  List<ConstantExpression> _computeList(List<ir.Expression> expressions) {
-    List<ConstantExpression> list = <ConstantExpression>[];
-    for (ir.Expression expression in expressions) {
-      ConstantExpression constant = visit(expression);
-      if (constant == null) return null;
-      list.add(constant);
-    }
-    return list;
-  }
-
-  List<ConstantExpression> _computeArguments(ir.Arguments node) {
-    List<ConstantExpression> arguments = <ConstantExpression>[];
-    for (ir.Expression argument in node.positional) {
-      ConstantExpression constant = visit(argument);
-      if (constant == null) return null;
-      arguments.add(constant);
-    }
-    for (ir.NamedExpression argument in node.named) {
-      ConstantExpression constant = visit(argument.value);
-      if (constant == null) return null;
-      arguments.add(constant);
-    }
-    return arguments;
-  }
-
-  ConstructedConstantExpression _computeConstructorInvocation(
-      ir.Constructor target, ir.Arguments arguments) {
-    List<ConstantExpression> expressions = _computeArguments(arguments);
-    if (expressions == null) return null;
-    return new ConstructedConstantExpression(
-        elementAdapter.createInterfaceType(
-            target.enclosingClass, arguments.types),
-        elementAdapter.getConstructor(target),
-        elementAdapter.getCallStructure(arguments),
-        expressions);
-  }
-
-  @override
-  ConstantExpression visitConstructorInvocation(ir.ConstructorInvocation node) {
-    return _computeConstructorInvocation(node.target, node.arguments);
-  }
-
-  @override
-  ConstantExpression visitVariableGet(ir.VariableGet node) {
-    if (node.variable.parent is ir.FunctionNode) {
-      ir.FunctionNode function = node.variable.parent;
-      int index = function.positionalParameters.indexOf(node.variable);
-      if (index != -1) {
-        return new PositionalArgumentReference(index);
-      } else {
-        assert(function.namedParameters.contains(node.variable));
-        return new NamedArgumentReference(node.variable.name);
-      }
-    } else if (node.variable.isConst) {
-      return visit(node.variable.initializer);
-    }
-    return defaultExpression(node);
-  }
-
-  @override
-  ConstantExpression visitStaticGet(ir.StaticGet node) {
-    ir.Member target = node.target;
-    if (target is ir.Field && target.isConst) {
-      return new FieldConstantExpression(elementAdapter.getField(node.target));
-    } else if (node.target is ir.Procedure) {
-      FunctionEntity function = elementAdapter.getMethod(node.target);
-      DartType type = elementAdapter.getFunctionType(node.target.function);
-      return new FunctionConstantExpression(function, type);
-    }
-    return defaultExpression(node);
-  }
-
-  @override
-  ConstantExpression visitNullLiteral(ir.NullLiteral node) {
-    return new NullConstantExpression();
-  }
-
-  @override
-  ConstantExpression visitBoolLiteral(ir.BoolLiteral node) {
-    return new BoolConstantExpression(node.value);
-  }
-
-  @override
-  ConstantExpression visitIntLiteral(ir.IntLiteral node) {
-    return new IntConstantExpression(node.value);
-  }
-
-  @override
-  ConstantExpression visitDoubleLiteral(ir.DoubleLiteral node) {
-    return new DoubleConstantExpression(node.value);
-  }
-
-  @override
-  ConstantExpression visitStringLiteral(ir.StringLiteral node) {
-    return new StringConstantExpression(node.value);
-  }
-
-  @override
-  ConstantExpression visitSymbolLiteral(ir.SymbolLiteral node) {
-    return new SymbolConstantExpression(node.value);
-  }
-
-  @override
-  ConstantExpression visitStringConcatenation(ir.StringConcatenation node) {
-    List<ConstantExpression> expressions = _computeList(node.expressions);
-    if (expressions == null) return null;
-    return new ConcatenateConstantExpression(expressions);
-  }
-
-  @override
-  ConstantExpression visitMapLiteral(ir.MapLiteral node) {
-    if (!node.isConst) {
-      return defaultExpression(node);
-    }
-    DartType keyType = elementAdapter.getDartType(node.keyType);
-    DartType valueType = elementAdapter.getDartType(node.valueType);
-    List<ConstantExpression> keys = <ConstantExpression>[];
-    List<ConstantExpression> values = <ConstantExpression>[];
-    for (ir.MapEntry entry in node.entries) {
-      ConstantExpression key = visit(entry.key);
-      if (key == null) return null;
-      keys.add(key);
-      ConstantExpression value = visit(entry.value);
-      if (value == null) return null;
-      values.add(value);
-    }
-    return new MapConstantExpression(
-        _commonElements.mapType(keyType, valueType), keys, values);
-  }
-
-  @override
-  ConstantExpression visitListLiteral(ir.ListLiteral node) {
-    if (!node.isConst) {
-      return defaultExpression(node);
-    }
-    DartType elementType = elementAdapter.getDartType(node.typeArgument);
-    List<ConstantExpression> values = <ConstantExpression>[];
-    for (ir.Expression expression in node.expressions) {
-      ConstantExpression value = visit(expression);
-      if (value == null) return null;
-      values.add(value);
-    }
-    return new ListConstantExpression(
-        _commonElements.listType(elementType), values);
-  }
-
-  @override
-  ConstantExpression visitTypeLiteral(ir.TypeLiteral node) {
-    DartType type = elementAdapter.getDartType(node.type);
-    String name;
-    if (type.isDynamic) {
-      name = 'dynamic';
-    } else if (type is InterfaceType) {
-      name = type.element.name;
-    } else if (type.isFunctionType || type.isTypedef) {
-      // TODO(johnniwinther): Compute a name for the type literal? It is only
-      // used in error messages in the old SSA builder.
-      name = '?';
-    } else {
-      return defaultExpression(node);
-    }
-    return new TypeConstantExpression(type, name);
-  }
-
-  @override
-  ConstantExpression visitNot(ir.Not node) {
-    ConstantExpression expression = visit(node.operand);
-    if (expression == null) return null;
-    return new UnaryConstantExpression(UnaryOperator.NOT, expression);
-  }
-
-  @override
-  ConstantExpression visitConditionalExpression(ir.ConditionalExpression node) {
-    ConstantExpression condition = visit(node.condition);
-    if (condition == null) return null;
-    ConstantExpression trueExp = visit(node.then);
-    if (trueExp == null) return null;
-    ConstantExpression falseExp = visit(node.otherwise);
-    if (falseExp == null) return null;
-    return new ConditionalConstantExpression(condition, trueExp, falseExp);
-  }
-
-  @override
-  ConstantExpression visitPropertyGet(ir.PropertyGet node) {
-    if (node.name.name != 'length') {
-      throw new UnimplementedError(
-          'Unexpected constant expression $node (${node.runtimeType})');
-    }
-    ConstantExpression receiver = visit(node.receiver);
-    if (receiver == null) return null;
-    return new StringLengthConstantExpression(receiver);
-  }
-
-  @override
-  ConstantExpression visitMethodInvocation(ir.MethodInvocation node) {
-    // Method invocations are generally not constant expressions but unary
-    // and binary expressions are encoded as method invocations in kernel.
-    if (node.arguments.named.isNotEmpty) {
-      return defaultExpression(node);
-    }
-    if (node.arguments.positional.length == 0) {
-      UnaryOperator operator;
-      if (node.name.name == UnaryOperator.NEGATE.selectorName) {
-        operator = UnaryOperator.NEGATE;
-      } else {
-        operator = UnaryOperator.parse(node.name.name);
-      }
-      if (operator != null) {
-        ConstantExpression expression = visit(node.receiver);
-        if (expression == null) return null;
-        return new UnaryConstantExpression(operator, expression);
-      }
-    }
-    if (node.arguments.positional.length == 1) {
-      BinaryOperator operator = BinaryOperator.parse(node.name.name);
-      if (operator != null) {
-        ConstantExpression left = visit(node.receiver);
-        if (left == null) return null;
-        ConstantExpression right = visit(node.arguments.positional.single);
-        if (right == null) return null;
-        return new BinaryConstantExpression(left, operator, right);
-      }
-    }
-    return defaultExpression(node);
-  }
-
-  @override
-  ConstantExpression visitStaticInvocation(ir.StaticInvocation node) {
-    MemberEntity member = elementAdapter.getMember(node.target);
-    if (member == _commonElements.identicalFunction) {
-      if (node.arguments.positional.length == 2 &&
-          node.arguments.named.isEmpty) {
-        ConstantExpression left = visit(node.arguments.positional[0]);
-        if (left == null) return null;
-        ConstantExpression right = visit(node.arguments.positional[1]);
-        if (right == null) return null;
-        return new IdenticalConstantExpression(left, right);
-      }
-    } else if (member.name == 'fromEnvironment' &&
-        node.arguments.positional.length == 1) {
-      ConstantExpression name = visit(node.arguments.positional.single);
-      if (name == null) return null;
-      ConstantExpression defaultValue;
-      if (node.arguments.named.length == 1) {
-        if (node.arguments.named.single.name != 'defaultValue') {
-          return defaultExpression(node);
-        }
-        defaultValue = visit(node.arguments.named.single.value);
-        if (defaultValue == null) return null;
-      }
-      if (member.enclosingClass == _commonElements.boolClass) {
-        return new BoolFromEnvironmentConstantExpression(name, defaultValue);
-      } else if (member.enclosingClass == _commonElements.intClass) {
-        return new IntFromEnvironmentConstantExpression(name, defaultValue);
-      } else if (member.enclosingClass == _commonElements.stringClass) {
-        return new StringFromEnvironmentConstantExpression(name, defaultValue);
-      }
-    }
-    return defaultExpression(node);
-  }
-
-  @override
-  ConstantExpression visitLogicalExpression(ir.LogicalExpression node) {
-    BinaryOperator operator = BinaryOperator.parse(node.operator);
-    if (operator != null) {
-      ConstantExpression left = visit(node.left);
-      if (left == null) return null;
-      ConstantExpression right = visit(node.right);
-      if (right == null) return null;
-      return new BinaryConstantExpression(left, operator, right);
-    }
-    return defaultExpression(node);
-  }
-
-  @override
-  ConstantExpression visitLet(ir.Let node) {
-    ir.Expression body = node.body;
-    if (body is ir.ConditionalExpression) {
-      ir.Expression condition = body.condition;
-      if (condition is ir.MethodInvocation) {
-        ir.Expression receiver = condition.receiver;
-        ir.Expression otherwise = body.otherwise;
-        if (condition.name.name == BinaryOperator.EQ.name &&
-            receiver is ir.VariableGet &&
-            condition.arguments.positional.single is ir.NullLiteral &&
-            otherwise is ir.VariableGet) {
-          if (receiver.variable == node.variable &&
-              otherwise.variable == node.variable) {
-            // We have <left> ?? <right> encoded as:
-            //    let #1 = <left> in #1 == null ? <right> : #1
-            ConstantExpression left = visit(node.variable.initializer);
-            if (left == null) return null;
-            ConstantExpression right = visit(body.then);
-            if (right == null) return null;
-            // TODO(johnniwinther): Remove [IF_NULL] binary constant expression
-            // when the resolver is removed; then we no longer need the
-            // expressions to be structurally equivalence for equivalence
-            // testing.
-            return new BinaryConstantExpression(
-                left, BinaryOperator.IF_NULL, right);
-          }
-        }
-      }
-    }
-    return defaultExpression(node);
-  }
-
-  /// Compute the [ConstantConstructor] corresponding to the const constructor
-  /// [node].
-  ConstantConstructor computeConstantConstructor(ir.Constructor node) {
-    assert(node.isConst);
-    ir.Class cls = node.enclosingClass;
-    InterfaceType type = elementAdapter.elementEnvironment
-        .getThisType(elementAdapter.getClass(cls));
-
-    Map<dynamic, ConstantExpression> defaultValues =
-        <dynamic, ConstantExpression>{};
-    int parameterIndex = 0;
-    for (ir.VariableDeclaration parameter
-        in node.function.positionalParameters) {
-      if (parameterIndex >= node.function.requiredParameterCount) {
-        ConstantExpression defaultValue;
-        if (parameter.initializer != null) {
-          defaultValue = parameter.initializer.accept(this);
-        } else {
-          defaultValue = new NullConstantExpression();
-        }
-        if (defaultValue == null) return null;
-        defaultValues[parameterIndex] = defaultValue;
-      }
-      parameterIndex++;
-    }
-    for (ir.VariableDeclaration parameter in node.function.namedParameters) {
-      ConstantExpression defaultValue = parameter.initializer.accept(this);
-      if (defaultValue == null) return null;
-      defaultValues[parameter.name] = defaultValue;
-    }
-
-    bool isRedirecting = node.initializers.length == 1 &&
-        node.initializers.single is ir.RedirectingInitializer;
-
-    Map<FieldEntity, ConstantExpression> fieldMap =
-        <FieldEntity, ConstantExpression>{};
-
-    void registerField(ir.Field field, ConstantExpression constant) {
-      fieldMap[elementAdapter.getField(field)] = constant;
-    }
-
-    if (!isRedirecting) {
-      for (ir.Field field in cls.fields) {
-        if (field.isStatic) continue;
-        if (field.initializer != null) {
-          registerField(field, field.initializer.accept(this));
-        }
-      }
-    }
-
-    ConstructedConstantExpression superConstructorInvocation;
-    for (ir.Initializer initializer in node.initializers) {
-      if (initializer is ir.FieldInitializer) {
-        registerField(initializer.field, initializer.value.accept(this));
-      } else if (initializer is ir.SuperInitializer) {
-        superConstructorInvocation = _computeConstructorInvocation(
-            initializer.target, initializer.arguments);
-      } else if (initializer is ir.RedirectingInitializer) {
-        superConstructorInvocation = _computeConstructorInvocation(
-            initializer.target, initializer.arguments);
-      } else {
-        throw new UnsupportedError(
-            'Unexpected initializer $node (${node.runtimeType})');
-      }
-    }
-    if (isRedirecting) {
-      return new RedirectingGenerativeConstantConstructor(
-          defaultValues, superConstructorInvocation);
-    } else {
-      return new GenerativeConstantConstructor(
-          type, defaultValues, fieldMap, superConstructorInvocation);
-    }
-  }
-}
-
 /// Interface for type inference results for kernel IR nodes.
 abstract class KernelToTypeInferenceMap {
   /// Returns the inferred return type of [function].