Support runtime check of function types.

sdk/lib/_internal/compiler/implementation/closure.dart

Index: sdk/lib/_internal/compiler/implementation/closure.dart
diff --git a/sdk/lib/_internal/compiler/implementation/closure.dart b/sdk/lib/_internal/compiler/implementation/closure.dart
index 61ab9b20fe6c7c7d23c6cd4d8e0aa7670b5921c0..38153903b3c0c0fa57993f5737d1102ec24ad451 100644
--- a/sdk/lib/_internal/compiler/implementation/closure.dart
+++ b/sdk/lib/_internal/compiler/implementation/closure.dart
@@ -529,6 +529,12 @@ class ClosureTranslator extends Visitor {
         useLocal(newElement);
         cached.parametersWithSentinel[parameter] = newElement;
       }
+    } else if (node.isTypeTest) {
+      DartType type = elements.getType(node.typeAnnotationFromIsCheckOrCast);
+      analyzeType(type);
+    } else if (node.isTypeCast) {
+      DartType type = elements.getType(node.arguments.head);
+      analyzeType(type);
     }
     node.visitChildren(this);
   }
@@ -547,26 +553,28 @@ class ClosureTranslator extends Visitor {
 
   visitNewExpression(NewExpression node) {
     DartType type = elements.getType(node);
+    analyzeType(type);
+    node.visitChildren(this);
+  }
 
-    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);
-        }
+  void analyzeTypeVariables(DartType type) {
+    type.forEachTypeVariable((TypeVariableType typeVariable) {
+      useLocal(typeVariable.element);
+      // Field initializers are inlined and access the type variable as
+      // normal parameters.
+      if (!outermostElement.isField()) {
+        registerNeedsThis();
       }
-    }
+    });
+  }
 
+  void analyzeType(DartType type) {
+    // TODO(johnniwinther): Find out why this can be null.
+    if (type == null) return;
     if (outermostElement.isMember() &&
-        compiler.backend.needsRti(outermostElement.getEnclosingClass())) {
-      if (outermostElement.isConstructor() || outermostElement.isField()) {
+        compiler.backend.classNeedsRti(outermostElement.getEnclosingClass())) {
+      if (outermostElement.isConstructor() ||
+          outermostElement.isField()) {
         analyzeTypeVariables(type);
       } else if (outermostElement.isInstanceMember()) {
         if (type.containsTypeVariables) {
@@ -574,8 +582,6 @@ class ClosureTranslator extends Visitor {
         }
       }
     }
-
-    node.visitChildren(this);
   }
 
   // If variables that are declared in the [node] scope are captured and need
@@ -734,7 +740,7 @@ class ClosureTranslator extends Visitor {
       }
 
       if (currentElement.isFactoryConstructor() &&
-          compiler.backend.needsRti(currentElement.enclosingElement)) {
+          compiler.backend.classNeedsRti(currentElement.enclosingElement)) {
         // Declare the type parameters in the scope. Generative
         // constructors just use 'this'.
         ClassElement cls = currentElement.enclosingElement;
@@ -743,9 +749,18 @@ class ClosureTranslator extends Visitor {
         });
       }
 
+      DartType type = element.computeType(compiler);
       // Compute the function type and check for type variables in return or
       // parameter types.
-      if (element.computeType(compiler).containsTypeVariables) {
+      if (type.containsTypeVariables) {
+        registerNeedsThis();
+      }
+      // Ensure that closure that need runtime type information has access to
+      // this of the enclosing class.
+      if (element is FunctionElement &&
+          closureData.thisElement != null &&
+          type.containsTypeVariables &&
+          compiler.backend.methodNeedsRti(element)) {
         registerNeedsThis();
       }