Rename Type to DartType to avoid conflicts with the class Type in the core library.

lib/compiler/implementation/typechecker.dart

 // Copyright (c) 2012, 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.
 
 class TypeCheckerTask extends CompilerTask {
   TypeCheckerTask(Compiler compiler) : super(compiler);
   String get name => "Type checker";
 
   static const bool LOG_FAILURES = false;
 
   void check(Node tree, TreeElements elements) {
     measure(() {
       Visitor visitor =
           new TypeCheckerVisitor(compiler, elements, compiler.types);
       try {
         tree.accept(visitor);
       } on CancelTypeCheckException catch (e) {
         if (LOG_FAILURES) {
           // Do not warn about unimplemented features; log message instead.
           compiler.log("'${e.node}': ${e.reason}");
         }
       }
     });
   }
 }
 
-interface Type {
+interface DartType {
   SourceString get name();
   Element get element();
 
   /**
    * Returns the unaliased type of this type.
    *
    * The unaliased type of a typedef'd type is the unaliased type to which its
    * name is bound. The unaliased version of any other type is the type itself.
    *
    * For example, the unaliased type of [: typedef A Func<A,B>(B b) :] is the
    * function type [: (B) -> A :] and the unaliased type of
    * [: Func<int,String> :] is the function type [: (String) -> int :].
    */
-  Type unalias(Compiler compiler);
+  DartType unalias(Compiler compiler);
 }
 
-class TypeVariableType implements Type {
+class TypeVariableType implements DartType {
   final TypeVariableElement element;
 
   TypeVariableType(this.element);
 
   SourceString get name => element.name;
 
-  Type unalias(Compiler compiler) => this;
+  DartType unalias(Compiler compiler) => this;
 
   String toString() => name.slowToString();
 }
 
 /**
  * A statement type tracks whether a statement returns or may return.
  */
-class StatementType implements Type {
+class StatementType implements DartType {
   final String stringName;
   Element get element => null;
 
   SourceString get name => new SourceString(stringName);
 
   const StatementType(this.stringName);
 
   static const RETURNING = const StatementType('<returning>');
   static const NOT_RETURNING = const StatementType('<not returning>');
   static const MAYBE_RETURNING = const StatementType('<maybe returning>');
 
   /** Combine the information about two control-flow edges that are joined. */
   StatementType join(StatementType other) {
     return (this === other) ? this : MAYBE_RETURNING;
   }
 
-  Type unalias(Compiler compiler) => this;
+  DartType unalias(Compiler compiler) => this;
 
   String toString() => stringName;
 }
 
-class VoidType implements Type {
+class VoidType implements DartType {
   const VoidType(this.element);
   SourceString get name => element.name;
   final VoidElement element;
 
-  Type unalias(Compiler compiler) => this;
+  DartType unalias(Compiler compiler) => this;
 
   String toString() => name.slowToString();
 }
 
-class InterfaceType implements Type {
+class InterfaceType implements DartType {
   final Element element;
-  final Link<Type> arguments;
+  final Link<DartType> arguments;
 
   const InterfaceType(this.element,
-                      [this.arguments = const EmptyLink<Type>()]);
+                      [this.arguments = const EmptyLink<DartType>()]);
 
   SourceString get name => element.name;
 
-  Type unalias(Compiler compiler) => this;
+  DartType unalias(Compiler compiler) => this;
 
   String toString() {
     StringBuffer sb = new StringBuffer();
     sb.add(name.slowToString());
     if (!arguments.isEmpty()) {
       sb.add('<');
       arguments.printOn(sb, ', ');
       sb.add('>');
     }
     return sb.toString();
   }
 }
 
-class FunctionType implements Type {
+class FunctionType implements DartType {
   final Element element;
-  Type returnType;
-  Link<Type> parameterTypes;
+  DartType returnType;
+  Link<DartType> parameterTypes;
 
-  FunctionType(Type this.returnType, Link<Type> this.parameterTypes,
+  FunctionType(DartType this.returnType, Link<DartType> this.parameterTypes,
                Element this.element);
 
-  Type unalias(Compiler compiler) => this;
+  DartType unalias(Compiler compiler) => this;
 
   String toString() {
     StringBuffer sb = new StringBuffer();
     bool first = true;
     sb.add('(');
     parameterTypes.printOn(sb, ', ');
     sb.add(') -> ${returnType}');
     return sb.toString();
   }
 
   SourceString get name => const SourceString('Function');
 
   int computeArity() {
     int arity = 0;
     parameterTypes.forEach((_) { arity++; });
     return arity;
   }
 
   void initializeFrom(FunctionType other) {
     assert(returnType === null);
     assert(parameterTypes === null);
     returnType = other.returnType;
     parameterTypes = other.parameterTypes;
   }
 }
 
-class TypedefType implements Type {
+class TypedefType implements DartType {
   final TypedefElement element;
-  final Link<Type> typeArguments;
+  final Link<DartType> typeArguments;
 
   const TypedefType(this.element,
-      [this.typeArguments = const EmptyLink<Type>()]);
+      [this.typeArguments = const EmptyLink<DartType>()]);
 
   SourceString get name => element.name;
 
-  Type unalias(Compiler compiler) {
+  DartType unalias(Compiler compiler) {
     // TODO(ahe): This should be [ensureResolved].
     compiler.resolveTypedef(element);
     return element.alias.unalias(compiler);
   }
 
   String toString() {
     StringBuffer sb = new StringBuffer();
     sb.add(name.slowToString());
     if (!typeArguments.isEmpty()) {
       sb.add('<');
@@ skipping 14 matching lines @@
     : this.with(compiler, dynamicElement,
                 new LibraryElement(new Script(null, null)));
 
   Types.with(Compiler this.compiler,
              Element dynamicElement,
              LibraryElement library)
     : voidType = new VoidType(new VoidElement(library)),
       dynamicType = new InterfaceType(dynamicElement);
 
   /** Returns true if t is a subtype of s */
-  bool isSubtype(Type t, Type s) {
+  bool isSubtype(DartType t, DartType s) {
     if (t === s ||
         t === dynamicType ||
         s === dynamicType ||
         s.element === compiler.objectClass) {
       return true;
     }
     t = t.unalias(compiler);
     s = s.unalias(compiler);
 
     if (t is VoidType) {
       return false;
     } else if (t is InterfaceType) {
       if (s is !InterfaceType) return false;
       ClassElement tc = t.element;
       if (tc === s.element) return true;
-      for (Link<Type> supertypes = tc.allSupertypes;
+      for (Link<DartType> supertypes = tc.allSupertypes;
            supertypes != null && !supertypes.isEmpty();
            supertypes = supertypes.tail) {
-        Type supertype = supertypes.head;
+        DartType supertype = supertypes.head;
         if (supertype.element === s.element) return true;
       }
       return false;
     } else if (t is FunctionType) {
       if (s.element === compiler.functionClass) return true;
       if (s is !FunctionType) return false;
       FunctionType tf = t;
       FunctionType sf = s;
-      Link<Type> tps = tf.parameterTypes;
-      Link<Type> sps = sf.parameterTypes;
+      Link<DartType> tps = tf.parameterTypes;
+      Link<DartType> sps = sf.parameterTypes;
       while (!tps.isEmpty() && !sps.isEmpty()) {
         if (!isAssignable(tps.head, sps.head)) return false;
         tps = tps.tail;
         sps = sps.tail;
       }
       if (!tps.isEmpty() || !sps.isEmpty()) return false;
       if (!isAssignable(sf.returnType, tf.returnType)) return false;
       return true;
     } else if (t is TypeVariableType) {
       if (s is !TypeVariableType) return false;
       return (t.element === s.element);
     } else {
       throw 'internal error: unknown type kind';
     }
   }
 
-  bool isAssignable(Type r, Type s) {
+  bool isAssignable(DartType r, DartType s) {
     return isSubtype(r, s) || isSubtype(s, r);
   }
 }
 
 class CancelTypeCheckException {
   final Node node;
   final String reason;
 
   CancelTypeCheckException(this.node, this.reason);
 }
 
-class TypeCheckerVisitor implements Visitor<Type> {
+class TypeCheckerVisitor implements Visitor<DartType> {
   final Compiler compiler;
   final TreeElements elements;
   final Types types;
 
   Node lastSeenNode;
-  Type expectedReturnType;
+  DartType expectedReturnType;
   ClassElement currentClass;
 
-  Link<Type> cascadeTypes = const EmptyLink<Type>();
+  Link<DartType> cascadeTypes = const EmptyLink<DartType>();
 
-  Type intType;
-  Type doubleType;
-  Type boolType;
-  Type stringType;
-  Type objectType;
-  Type listType;
+  DartType intType;
+  DartType doubleType;
+  DartType boolType;
+  DartType stringType;
+  DartType objectType;
+  DartType listType;
 
   TypeCheckerVisitor(this.compiler, this.elements, this.types) {
     intType = compiler.intClass.computeType(compiler);
     doubleType = compiler.doubleClass.computeType(compiler);
     boolType = compiler.boolClass.computeType(compiler);
     stringType = compiler.stringClass.computeType(compiler);
     objectType = compiler.objectClass.computeType(compiler);
     listType = compiler.listClass.computeType(compiler);
   }
 
-  Type fail(node, [reason]) {
+  DartType fail(node, [reason]) {
     String message = 'cannot type-check';
     if (reason !== null) {
       message = '$message: $reason';
     }
     throw new CancelTypeCheckException(node, message);
   }
 
   reportTypeWarning(Node node, MessageKind kind, [List arguments = const []]) {
     compiler.reportWarning(node, new TypeWarning(kind, arguments));
   }
 
   // TODO(karlklose): remove these functions.
-  Type unhandledStatement() => StatementType.NOT_RETURNING;
-  Type unhandledExpression() => types.dynamicType;
+  DartType unhandledStatement() => StatementType.NOT_RETURNING;
+  DartType unhandledExpression() => types.dynamicType;
 
-  Type analyzeNonVoid(Node node) {
-    Type type = analyze(node);
+  DartType analyzeNonVoid(Node node) {
+    DartType type = analyze(node);
     if (type == types.voidType) {
       reportTypeWarning(node, MessageKind.VOID_EXPRESSION);
     }
     return type;
   }
 
-  Type analyzeWithDefault(Node node, Type defaultValue) {
+  DartType analyzeWithDefault(Node node, DartType defaultValue) {
     return node !== null ? analyze(node) : defaultValue;
   }
 
-  Type analyze(Node node) {
+  DartType analyze(Node node) {
     if (node == null) {
       final String error = 'internal error: unexpected node: null';
       if (lastSeenNode != null) {
         fail(null, error);
       } else {
         compiler.cancel(error);
       }
     } else {
       lastSeenNode = node;
     }
-    Type result = node.accept(this);
+    DartType result = node.accept(this);
     // TODO(karlklose): record type?
     if (result === null) {
       fail(node, 'internal error: type is null');
     }
     return result;
   }
 
   /**
    * Check if a value of type t can be assigned to a variable,
    * parameter or return value of type s.
    */
-  checkAssignable(Node node, Type s, Type t) {
+  checkAssignable(Node node, DartType s, DartType t) {
     if (!types.isAssignable(s, t)) {
       reportTypeWarning(node, MessageKind.NOT_ASSIGNABLE, [s, t]);
     }
   }
 
   checkCondition(Expression condition) {
     checkAssignable(condition, boolType, analyze(condition));
   }
 
-  void pushCascadeType(Type type) {
+  void pushCascadeType(DartType type) {
     cascadeTypes = cascadeTypes.prepend(type);
   }
 
-  Type popCascadeType() {
-    Type type = cascadeTypes.head;
+  DartType popCascadeType() {
+    DartType type = cascadeTypes.head;
     cascadeTypes = cascadeTypes.tail;
     return type;
   }
 
-  Type visitBlock(Block node) {
+  DartType visitBlock(Block node) {
     return analyze(node.statements);
   }
 
-  Type visitCascade(Cascade node) {
+  DartType visitCascade(Cascade node) {
     analyze(node.expression);
     return popCascadeType();
   }
 
-  Type visitCascadeReceiver(CascadeReceiver node) {
-    Type type = analyze(node.expression);
+  DartType visitCascadeReceiver(CascadeReceiver node) {
+    DartType type = analyze(node.expression);
     pushCascadeType(type);
     return type;
   }
 
-  Type visitClassNode(ClassNode node) {
+  DartType visitClassNode(ClassNode node) {
     fail(node);
   }
 
-  Type visitDoWhile(DoWhile node) {
+  DartType visitDoWhile(DoWhile node) {
     StatementType bodyType = analyze(node.body);
     checkCondition(node.condition);
     return bodyType.join(StatementType.NOT_RETURNING);
   }
 
-  Type visitExpressionStatement(ExpressionStatement node) {
+  DartType visitExpressionStatement(ExpressionStatement node) {
     analyze(node.expression);
     return StatementType.NOT_RETURNING;
   }
 
   /** Dart Programming Language Specification: 11.5.1 For Loop */
-  Type visitFor(For node) {
+  DartType visitFor(For node) {
     analyzeWithDefault(node.initializer, StatementType.NOT_RETURNING);
     checkCondition(node.condition);
     analyzeWithDefault(node.update, StatementType.NOT_RETURNING);
     StatementType bodyType = analyze(node.body);
     return bodyType.join(StatementType.NOT_RETURNING);
   }
 
-  Type visitFunctionDeclaration(FunctionDeclaration node) {
+  DartType visitFunctionDeclaration(FunctionDeclaration node) {
     analyze(node.function);
     return StatementType.NOT_RETURNING;
   }
 
-  Type visitFunctionExpression(FunctionExpression node) {
-    Type type;
-    Type returnType;
-    Type previousType;
+  DartType visitFunctionExpression(FunctionExpression node) {
+    DartType type;
+    DartType returnType;
+    DartType previousType;
     final FunctionElement element = elements[node];
     if (Element.isInvalid(element)) return types.dynamicType;
     if (element.kind === ElementKind.GENERATIVE_CONSTRUCTOR ||
         element.kind === ElementKind.GENERATIVE_CONSTRUCTOR_BODY) {
       type = types.dynamicType;
       returnType = types.voidType;
     } else {
       FunctionType functionType = computeType(element);
       returnType = functionType.returnType;
       type = functionType;
     }
-    Type previous = expectedReturnType;
+    DartType previous = expectedReturnType;
     expectedReturnType = returnType;
     if (element.isMember()) currentClass = element.getEnclosingClass();
     StatementType bodyType = analyze(node.body);
     if (returnType != types.voidType && returnType != types.dynamicType
         && bodyType != StatementType.RETURNING) {
       MessageKind kind;
       if (bodyType == StatementType.MAYBE_RETURNING) {
         kind = MessageKind.MAYBE_MISSING_RETURN;
       } else {
         kind = MessageKind.MISSING_RETURN;
       }
       reportTypeWarning(node.name, kind);
     }
     expectedReturnType = previous;
     return type;
   }
 
-  Type visitIdentifier(Identifier node) {
+  DartType visitIdentifier(Identifier node) {
     if (node.isThis()) {
       return currentClass.computeType(compiler);
     } else {
       // This is an identifier of a formal parameter.
       return types.dynamicType;
     }
   }
 
-  Type visitIf(If node) {
+  DartType visitIf(If node) {
     checkCondition(node.condition);
     StatementType thenType = analyze(node.thenPart);
     StatementType elseType = node.hasElsePart ? analyze(node.elsePart)
                                               : StatementType.NOT_RETURNING;
     return thenType.join(elseType);
   }
 
-  Type visitLoop(Loop node) {
+  DartType visitLoop(Loop node) {
     return unhandledStatement();
   }
 
-  Type lookupMethodType(Node node, ClassElement classElement,
+  DartType lookupMethodType(Node node, ClassElement classElement,
                         SourceString name) {
     Element member = classElement.lookupLocalMember(name);
     if (member === null) {
       classElement.ensureResolved(compiler);
-      for (Link<Type> supertypes = classElement.allSupertypes;
+      for (Link<DartType> supertypes = classElement.allSupertypes;
            !supertypes.isEmpty() && member === null;
            supertypes = supertypes.tail) {
         ClassElement lookupTarget = supertypes.head.element;
         member = lookupTarget.lookupLocalMember(name);
       }
     }
     if (member !== null && member.kind == ElementKind.FUNCTION) {
       return computeType(member);
     }
     reportTypeWarning(node, MessageKind.METHOD_NOT_FOUND,
                       [classElement.name, name]);
     return types.dynamicType;
   }
 
-  void analyzeArguments(Send send, Type type) {
+  void analyzeArguments(Send send, DartType type) {
     Link<Node> arguments = send.arguments;
     if (type === null || type === types.dynamicType) {
       while(!arguments.isEmpty()) {
         analyze(arguments.head);
         arguments = arguments.tail;
       }
     } else {
       FunctionType funType = type;
-      Link<Type> parameterTypes = funType.parameterTypes;
+      Link<DartType> parameterTypes = funType.parameterTypes;
       while (!arguments.isEmpty() && !parameterTypes.isEmpty()) {
         checkAssignable(arguments.head, parameterTypes.head,
                         analyze(arguments.head));
         arguments = arguments.tail;
         parameterTypes = parameterTypes.tail;
       }
       if (!arguments.isEmpty()) {
         reportTypeWarning(arguments.head, MessageKind.ADDITIONAL_ARGUMENT);
       } else if (!parameterTypes.isEmpty()) {
         reportTypeWarning(send, MessageKind.MISSING_ARGUMENT,
                           [parameterTypes.head]);
       }
     }
   }
 
-  Type visitSend(Send node) {
+  DartType visitSend(Send node) {
     Element element = elements[node];
 
     if (Elements.isClosureSend(node, element)) {
       // TODO(karlklose): Finish implementation.
       return types.dynamicType;
     }
 
     Identifier selector = node.selector.asIdentifier();
     String name = selector.source.stringValue;
 
     if (node.isOperator && name === 'is') {
       analyze(node.receiver);
       return boolType;
     } else if (node.isOperator) {
       final Node firstArgument = node.receiver;
-      final Type firstArgumentType = analyze(node.receiver);
+      final DartType firstArgumentType = analyze(node.receiver);
       final arguments = node.arguments;
       final Node secondArgument = arguments.isEmpty() ? null : arguments.head;
-      final Type secondArgumentType = analyzeWithDefault(secondArgument, null);
+      final DartType secondArgumentType =
+          analyzeWithDefault(secondArgument, null);
 
       if (name === '+' || name === '=' || name === '-'
           || name === '*' || name === '/' || name === '%'
           || name === '~/' || name === '|' || name ==='&'
           || name === '^' || name === '~'|| name === '<<'
           || name === '>>' || name === '[]') {
         return types.dynamicType;
       } else if (name === '<' || name === '>' || name === '<='
                  || name === '>=' || name === '==' || name === '!='
                  || name === '===' || name === '!==') {
@@ skipping 15 matching lines @@
       }
       if (element === null) return types.dynamicType;
       return computeType(element);
 
     } else if (node.isFunctionObjectInvocation) {
       fail(node.receiver, 'function object invocation unimplemented');
 
     } else {
       FunctionType computeFunType() {
         if (node.receiver !== null) {
-          Type receiverType = analyze(node.receiver);
+          DartType receiverType = analyze(node.receiver);
           if (receiverType.element == compiler.dynamicClass) return null;
           if (receiverType === null) {
             fail(node.receiver, 'receivertype is null');
           }
           if (receiverType.element.kind === ElementKind.GETTER) {
             FunctionType getterType  = receiverType;
             receiverType = getterType.returnType;
           }
           ElementKind receiverKind = receiverType.element.kind;
           if (receiverKind === ElementKind.TYPEDEF) {
             // TODO(karlklose): handle typedefs.
             return null;
           }
           if (receiverKind === ElementKind.TYPE_VARIABLE) {
             // TODO(karlklose): handle type variables.
             return null;
           }
           if (receiverKind !== ElementKind.CLASS) {
             fail(node.receiver, 'unexpected receiver kind: ${receiverKind}');
           }
           ClassElement classElement = receiverType.element;
           // TODO(karlklose): substitute type arguments.
-          Type memberType =
+          DartType memberType =
             lookupMethodType(selector, classElement, selector.source);
           if (memberType.element === compiler.dynamicClass) return null;
           return memberType;
         } else {
           if (element === null) {
             fail(node, 'unresolved ${node.selector}');
           } else if (element.kind === ElementKind.FUNCTION) {
             return computeType(element);
           } else if (element.kind === ElementKind.FOREIGN) {
             return null;
@@ skipping 10 matching lines @@
       analyzeArguments(node, funType);
       return (funType !== null) ? funType.returnType : types.dynamicType;
     }
   }
 
   visitSendSet(SendSet node) {
     Identifier selector = node.selector;
     final name = node.assignmentOperator.source.stringValue;
     if (name === '++' || name === '--') {
       final Element element = elements[node.selector];
-      final Type receiverType = computeType(element);
+      final DartType receiverType = computeType(element);
       // TODO(karlklose): this should be the return type instead of int.
       return node.isPrefix ? intType : receiverType;
     } else {
-      Type targetType = computeType(elements[node]);
+      DartType targetType = computeType(elements[node]);
       Node value = node.arguments.head;
       checkAssignable(value, targetType, analyze(value));
       return targetType;
     }
   }
 
-  Type visitLiteralInt(LiteralInt node) {
+  DartType visitLiteralInt(LiteralInt node) {
     return intType;
   }
 
-  Type visitLiteralDouble(LiteralDouble node) {
+  DartType visitLiteralDouble(LiteralDouble node) {
     return doubleType;
   }
 
-  Type visitLiteralBool(LiteralBool node) {
+  DartType visitLiteralBool(LiteralBool node) {
     return boolType;
   }
 
-  Type visitLiteralString(LiteralString node) {
+  DartType visitLiteralString(LiteralString node) {
     return stringType;
   }
 
-  Type visitStringJuxtaposition(StringJuxtaposition node) {
+  DartType visitStringJuxtaposition(StringJuxtaposition node) {
     analyze(node.first);
     analyze(node.second);
     return stringType;
   }
 
-  Type visitLiteralNull(LiteralNull node) {
+  DartType visitLiteralNull(LiteralNull node) {
     return types.dynamicType;
   }
 
-  Type visitNewExpression(NewExpression node) {
+  DartType visitNewExpression(NewExpression node) {
     Element element = elements[node.send];
     analyzeArguments(node.send, computeType(element));
     return analyze(node.send.selector);
   }
 
-  Type visitLiteralList(LiteralList node) {
+  DartType visitLiteralList(LiteralList node) {
     return listType;
   }
 
-  Type visitNodeList(NodeList node) {
-    Type type = StatementType.NOT_RETURNING;
+  DartType visitNodeList(NodeList node) {
+    DartType type = StatementType.NOT_RETURNING;
     bool reportedDeadCode = false;
     for (Link<Node> link = node.nodes; !link.isEmpty(); link = link.tail) {
-      Type nextType = analyze(link.head);
+      DartType nextType = analyze(link.head);
       if (type == StatementType.RETURNING) {
         if (!reportedDeadCode) {
           reportTypeWarning(link.head, MessageKind.UNREACHABLE_CODE);
           reportedDeadCode = true;
         }
       } else if (type == StatementType.MAYBE_RETURNING){
         if (nextType == StatementType.RETURNING) {
           type = nextType;
         }
       } else {
         type = nextType;
       }
     }
     return type;
   }
 
-  Type visitOperator(Operator node) {
+  DartType visitOperator(Operator node) {
     fail(node, 'internal error');
   }
 
   /** Dart Programming Language Specification: 11.10 Return */
-  Type visitReturn(Return node) {
+  DartType visitReturn(Return node) {
     if (node.getBeginToken().stringValue === 'native') {
       return StatementType.RETURNING;
     }
 
     final expression = node.expression;
     final isVoidFunction = (expectedReturnType === types.voidType);
 
     // Executing a return statement return e; [...] It is a static type warning
     // if the type of e may not be assigned to the declared return type of the
     // immediately enclosing function.
@@ skipping 11 matching lines @@
     // form 'return;' It is a static warning if both of the following conditions
     // hold:
     // - f is not a generative constructor.
     // - The return type of f may not be assigned to void.
     } else if (!types.isAssignable(expectedReturnType, types.voidType)) {
       reportTypeWarning(node, MessageKind.RETURN_NOTHING, [expectedReturnType]);
     }
     return StatementType.RETURNING;
   }
 
-  Type visitThrow(Throw node) {
+  DartType visitThrow(Throw node) {
     if (node.expression !== null) analyze(node.expression);
     return StatementType.RETURNING;
   }
 
-  Type computeType(Element element) {
+  DartType computeType(Element element) {
     if (Element.isInvalid(element)) return types.dynamicType;
-    Type result = element.computeType(compiler);
+    DartType result = element.computeType(compiler);
     return (result !== null) ? result : types.dynamicType;
   }
 
-  Type visitTypeAnnotation(TypeAnnotation node) {
+  DartType visitTypeAnnotation(TypeAnnotation node) {
     return elements.getType(node);
   }
 
   visitTypeVariable(TypeVariable node) {
     return types.dynamicType;
   }
 
-  Type visitVariableDefinitions(VariableDefinitions node) {
-    Type type = analyzeWithDefault(node.type, types.dynamicType);
+  DartType visitVariableDefinitions(VariableDefinitions node) {
+    DartType type = analyzeWithDefault(node.type, types.dynamicType);
     if (type == types.voidType) {
       reportTypeWarning(node.type, MessageKind.VOID_VARIABLE);
       type = types.dynamicType;
     }
     for (Link<Node> link = node.definitions.nodes; !link.isEmpty();
          link = link.tail) {
       Node initialization = link.head;
       compiler.ensure(initialization is Identifier
                       || initialization is Send);
       if (initialization is Send) {
-        Type initializer = analyzeNonVoid(link.head);
+        DartType initializer = analyzeNonVoid(link.head);
         checkAssignable(node, type, initializer);
       }
     }
     return StatementType.NOT_RETURNING;
   }
 
-  Type visitWhile(While node) {
+  DartType visitWhile(While node) {
     checkCondition(node.condition);
     StatementType bodyType = analyze(node.body);
     Expression cond = node.condition.asParenthesizedExpression().expression;
     if (cond.asLiteralBool() !== null && cond.asLiteralBool().value == true) {
       // If the condition is a constant boolean expression denoting true,
       // control-flow always enters the loop body.
       // TODO(karlklose): this should be StatementType.RETURNING unless there
       // is a break in the loop body that has the loop or a label outside the
       // loop as a target.
       return bodyType;
     } else {
       return bodyType.join(StatementType.NOT_RETURNING);
     }
   }
 
-  Type visitParenthesizedExpression(ParenthesizedExpression node) {
+  DartType visitParenthesizedExpression(ParenthesizedExpression node) {
     return analyze(node.expression);
   }
 
-  Type visitConditional(Conditional node) {
+  DartType visitConditional(Conditional node) {
     checkCondition(node.condition);
-    Type thenType = analyzeNonVoid(node.thenExpression);
-    Type elseType = analyzeNonVoid(node.elseExpression);
+    DartType thenType = analyzeNonVoid(node.thenExpression);
+    DartType elseType = analyzeNonVoid(node.elseExpression);
     if (types.isSubtype(thenType, elseType)) {
       return thenType;
     } else if (types.isSubtype(elseType, thenType)) {
       return elseType;
     } else {
       return objectType;
     }
   }
 
-  Type visitModifiers(Modifiers node) {}
+  DartType visitModifiers(Modifiers node) {}
 
   visitStringInterpolation(StringInterpolation node) {
     node.visitChildren(this);
     return stringType;
   }
 
   visitStringInterpolationPart(StringInterpolationPart node) {
     node.visitChildren(this);
     return stringType;
   }
@@ skipping 55 matching lines @@
   }
 
   visitCatchBlock(CatchBlock node) {
     return unhandledStatement();
   }
 
   visitTypedef(Typedef node) {
     return unhandledStatement();
   }
 }