Fix type variables in closures.

sdk/lib/_internal/compiler/implementation/closure.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.
 
 library closureToClassMapper;
 
 import "elements/elements.dart";
 import "dart2jslib.dart";
 import "dart_types.dart";
 import "scanner/scannerlib.dart" show Token;
@@ skipping 459 matching lines @@
     // from a parameter which has been analyzed before the method has been
     // resolved and the result has been thrown away.
     if (compiler.enableTypeAssertions && type != null &&
         type.containsTypeVariables) {
       if (insideClosure && member.isFactoryConstructor()) {
         // This is a closure in a factory constructor.  Since there is no
         // [:this:], we have to mark the type arguments as free variables to
         // capture them in the closure.
         type.forEachTypeVariable((variable) => useLocal(variable.element));
       }
-      // TODO(karlklose): try to get rid of the isField check; there is a bug
-      // with type variable use in field initializer (in both modes).
       if (member.isInstanceMember() && !member.isField()) {
         // In checked mode, using a type variable in a type annotation may lead
         // to a runtime type check that needs to access the type argument and
-        // therefore the closure needs a this-element.
+        // therefore the closure needs a this-element, if it is not a field;

[ngeoffray, 2013/06/19 20:03:57]

not a field -> not declared in a field initializer?

[karlklose, 2013/06/20 10:18:00]

Done.

+        // field initatializers are evaluated in a context where the type
+        // arguments are available in locals.
         registerNeedsThis();
       }
     }
   }
 
   visitIdentifier(Identifier node) {
     if (node.isThis()) {
       registerNeedsThis();
     } else {
       Element element = elements[node];
       if (element != null && element.kind == ElementKind.TYPE_VARIABLE) {
         registerNeedsThis();
       }
     }
     node.visitChildren(this);
   }
 
   visitSend(Send node) {
     Element element = elements[node];
     if (Elements.isLocal(element)) {
       useLocal(element);
     } else if (node.receiver == null &&
                Elements.isInstanceSend(node, elements)) {
       registerNeedsThis();
     } else if (node.isSuperCall) {
       registerNeedsThis();
+    } else if (node.isIsCheck || node.isIsNotCheck || node.isTypeCast) {
+      TypeAnnotation annotation = node.typeAnnotationFromIsCheck;
+      DartType type = elements.getType(annotation);
+      if (type != null && type.containsTypeVariables) {
+        registerNeedsThis();
+      }
     } else if (node.isParameterCheck) {
       Element parameter = elements[node.receiver];
       FunctionElement enclosing = parameter.enclosingElement;
       FunctionExpression function = enclosing.parseNode(compiler);
       ClosureClassMap cached = closureMappingCache[function];
       if (!cached.parametersWithSentinel.containsKey(parameter)) {
         SourceString parameterName = parameter.name;
         String name = '${parameterName.slowToString()}_check';
         Element newElement = new CheckVariableElement(new SourceString(name),
                                                       parameter,
@@ skipping 13 matching lines @@
     if (Elements.isLocal(element) &&
         element.computeType(compiler).containsTypeVariables) {
       registerNeedsThis();
     }
     super.visitSendSet(node);
   }
 
   visitNewExpression(NewExpression node) {
     DartType type = elements.getType(node);
 
-    bool hasTypeVariable(DartType type) {
-      if (type is TypeVariableType) {
-        return true;
-      } else if (type is InterfaceType) {
-        InterfaceType ifcType = type;
-        for (DartType argument in ifcType.typeArguments) {
-          if (hasTypeVariable(argument)) {
-            return true;
-          }
-        }
-      }
-      return false;
-    }
-
     void analyzeTypeVariables(DartType type) {
       if (type is TypeVariableType) {
         useLocal(type.element);
+        // Field initializers are inlined and access the type variable as
+        // normal parameters.
+        if (!outermostElement.isField()) {
+          registerNeedsThis();
+        }
       } else if (type is InterfaceType) {
         InterfaceType ifcType = type;
         for (DartType argument in ifcType.typeArguments) {
           analyzeTypeVariables(argument);
         }
       }
     }
 
     if (outermostElement.isMember() &&
         compiler.backend.needsRti(outermostElement.getEnclosingClass())) {
       if (outermostElement.isConstructor() || outermostElement.isField()) {
         analyzeTypeVariables(type);
       } else if (outermostElement.isInstanceMember()) {
-        if (hasTypeVariable(type)) {
+        if (type.containsTypeVariables) {
           registerNeedsThis();
         }
       }
     }
 
     node.visitChildren(this);
   }
 
   // If variables that are declared in the [node] scope are captured and need
   // to be boxed create a box-element and update the [capturingScopes] in the
@@ skipping 216 matching lines @@
   }
 
   visitTryStatement(TryStatement node) {
     // TODO(ngeoffray): implement finer grain state.
     bool oldInTryStatement = inTryStatement;
     inTryStatement = true;
     node.visitChildren(this);
     inTryStatement = oldInTryStatement;
   }
 }