Clean up handling of types.

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 final bool LOG_FAILURES = false;
 
@@ skipping 101 matching lines @@
   static final DOUBLE = const SourceString('double');
   static final DYNAMIC = const SourceString('Dynamic');
   static final STRING = const SourceString('String');
   static final BOOL = const SourceString('bool');
   static final OBJECT = const SourceString('Object');
   static final LIST = const SourceString('List');
 
   final SimpleType voidType;
   final SimpleType dynamicType;
 
-  Types() : this.with(new LibraryElement(new Script(null, null)));
+  Types(Element dynamicElement)
+    : this.with(dynamicElement, new LibraryElement(new Script(null, null)));
 
-  Types.with(LibraryElement library)
+  Types.with(Element dynamicElement, LibraryElement library)
     : voidType = new SimpleType(VOID, new ClassElement(VOID, library)),

[ahe, 2012/04/17 16:14:47]

Perhaps we should have a Void class as well.

[karlklose, 2012/04/18 08:19:08]

I am not sure, I added a TODO for now.

[ahe, 2012/04/18 08:49:04]

Good plan.

-      dynamicType = new SimpleType(DYNAMIC, new ClassElement(DYNAMIC, library));
+      dynamicType = new SimpleType(DYNAMIC, dynamicElement);
 
   Type lookup(SourceString s) {
     if (VOID == s) {
       return voidType;
     } else if (DYNAMIC == s || s.stringValue === 'var') {
       return dynamicType;
     }
     return null;
   }
 
   /** Returns true if t is a subtype of s */
   bool isSubtype(Type t, Type s) {
     if (t === s || t === dynamicType || s === dynamicType ||
         s.name == OBJECT) return true;
-    if (t is SimpleType) {
-      if (s is !SimpleType) return false;
+    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;
            supertypes != null && !supertypes.isEmpty();
            supertypes = supertypes.tail) {
         Type supertype = supertypes.head;
         if (supertype.element === s.element) return true;
       }
       return false;
     } else if (t is FunctionType) {
       if (s is !FunctionType) return false;
       FunctionType tf = t;
       FunctionType sf = s;
       Link<Type> tps = tf.parameterTypes;
       Link<Type> 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) {
     return isSubtype(r, s) || isSubtype(s, r);
   }
 }
 
 class CancelTypeCheckException {
   final Node node;
   final String reason;
 
   CancelTypeCheckException(this.node, this.reason);
 }
 
-Type lookupType(SourceString name, Compiler compiler, types) {
-  Type t = types.lookup(name);
-  if (t !== null) return t;
-  Element element = compiler.coreLibrary.find(name);
-  if (element !== null && element.kind === ElementKind.CLASS) {
-    return element.computeType(compiler);
-  }
-  return null;
-}
-
 class TypeCheckerVisitor implements Visitor<Type> {
   final Compiler compiler;
   final TreeElements elements;
   final Types types;
 
   Node lastSeenNode;
   Type expectedReturnType;
   ClassElement currentClass;
 
   Link<Type> cascadeTypes = const EmptyLink<Type>();
 
   Type intType;
   Type doubleType;
   Type boolType;
   Type stringType;
   Type objectType;
   Type listType;
 
   TypeCheckerVisitor(this.compiler, this.elements, this.types) {
-    intType = lookupType(Types.INT, compiler, types);
-    doubleType = lookupType(Types.DOUBLE, compiler, types);
-    boolType = lookupType(Types.BOOL, compiler, types);
-    stringType = lookupType(Types.STRING, compiler, types);
-    objectType = lookupType(Types.OBJECT, compiler, types);
-    listType = lookupType(Types.LIST, compiler, 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]) {
     String message = 'cannot type-check';
     if (reason !== null) {
       message = '$message: $reason';
     }
     throw new CancelTypeCheckException(node, message);
   }
 
@@ skipping 391 matching lines @@
     return StatementType.RETURNING;
   }
 
   Type computeType(Element element) {
     if (element === null) return types.dynamicType;
     Type result = element.computeType(compiler);
     return (result !== null) ? result : types.dynamicType;
   }
 
   Type visitTypeAnnotation(TypeAnnotation node) {
-    if (node.typeName === null) return types.dynamicType;
-    Identifier identifier = node.typeName.asIdentifier();
-    if (identifier === null) {
-      fail(node.typeName, 'library prefix not implemented');
-    }
-    // TODO(ahe): Why wasn't this resolved by the resolver?
-    Type type = lookupType(identifier.source, compiler, types);
-    if (type === null) {
-      // The type name cannot be resolved, but the resolver
-      // already gave a warning, so we continue checking.
-      return types.dynamicType;
-    }
-    return type;
+    return elements.getType(node);
   }
 
   visitTypeVariable(TypeVariable node) {
     return types.dynamicType;
   }
 
   Type visitVariableDefinitions(VariableDefinitions node) {
     Type type = analyzeWithDefault(node.type, types.dynamicType);
     if (type == types.voidType) {
       reportTypeWarning(node.type, MessageKind.VOID_VARIABLE);
@@ skipping 98 matching lines @@
   }
 
   visitCatchBlock(CatchBlock node) {
     fail(node);
   }
 
   visitTypedef(Typedef node) {
     fail(node);
   }
 }