diff --git a/idea/src/org/jetbrains/jet/codegen/ClassCodegen.java b/idea/src/org/jetbrains/jet/codegen/ClassCodegen.java
index 36975870014..92af8158517 100644
--- a/idea/src/org/jetbrains/jet/codegen/ClassCodegen.java
+++ b/idea/src/org/jetbrains/jet/codegen/ClassCodegen.java
@@ -73,7 +73,7 @@ public class ClassCodegen {
         ClassVisitor v = kind == OwnerKind.IMPLEMENTATION ? factory.forClassImplementation(descriptor) : factory.forClassDelegatingImplementation(descriptor);
         v.visit(Opcodes.V1_6,
                 Opcodes.ACC_PUBLIC,
-                JetTypeMapper.jvmName(descriptor, kind),
+                JetTypeMapper.jetJvmName(descriptor, kind),
                 null,
                 superClass,
                 new String[] { "jet/JetObject", JetTypeMapper.jvmNameForInterface(descriptor) }
@@ -113,7 +113,7 @@ public class ClassCodegen {
         else if (first instanceof JetDelegatorToSuperCall) {
             JetType superType = bindingContext.resolveTypeReference(first.getTypeReference());
             ClassDescriptor superClassDescriptor = (ClassDescriptor) superType.getConstructor().getDeclarationDescriptor();
-            return JetTypeMapper.jvmName(superClassDescriptor, kind);
+            return typeMapper.jvmName(superClassDescriptor, kind);
         }
 
         return "java/lang/Object";
@@ -177,7 +177,7 @@ public class ClassCodegen {
         final InstructionAdapter iv = new InstructionAdapter(mv);
         ExpressionCodegen codegen = new ExpressionCodegen(mv, bindingContext, frameMap, typeMapper, Type.VOID_TYPE, classDescriptor, kind);
 
-        String classname = JetTypeMapper.jvmName(classDescriptor, kind);
+        String classname = typeMapper.jvmName(classDescriptor, kind);
         final Type classType = Type.getType("L" + classname + ";");
 
         if (kind == OwnerKind.DELEGATING_IMPLEMENTATION) {
diff --git a/idea/src/org/jetbrains/jet/codegen/ExpressionCodegen.java b/idea/src/org/jetbrains/jet/codegen/ExpressionCodegen.java
index 4260ee3e098..2071803269d 100644
--- a/idea/src/org/jetbrains/jet/codegen/ExpressionCodegen.java
+++ b/idea/src/org/jetbrains/jet/codegen/ExpressionCodegen.java
@@ -43,6 +43,7 @@ public class ExpressionCodegen extends JetVisitor {
     private static final String ITERATOR_NEXT_DESCRIPTOR = "()Ljava/lang/Object;";
     private static final String INT_RANGE_CONSTRUCTOR_DESCRIPTOR = "(II)V";
 
+    private static final Type OBJECT_TYPE = Type.getType(Object.class);
     private static final Type ITERATOR_TYPE = Type.getType(Iterator.class);
     private static final Type INT_RANGE_TYPE = Type.getType(IntRange.class);
     private static final Type JET_OBJECT_TYPE = Type.getType(JetObject.class);
@@ -501,11 +502,11 @@ public class ExpressionCodegen extends JetVisitor {
         String fieldOwner;
         String interfaceOwner;
         if (isInsideClass || isStatic) {
-            fieldOwner = interfaceOwner = JetTypeMapper.getOwner(propertyDescriptor, contextKind);
+            fieldOwner = interfaceOwner = typeMapper.getOwner(propertyDescriptor, contextKind);
         }
         else {
             fieldOwner = null;
-            interfaceOwner = JetTypeMapper.getOwner(propertyDescriptor, OwnerKind.INTERFACE);
+            interfaceOwner = typeMapper.getOwner(propertyDescriptor, OwnerKind.INTERFACE);
         }
 
         return StackValue.property(propertyDescriptor.getName(), fieldOwner, interfaceOwner, typeMapper.mapType(outType), isStatic, getter, setter);
@@ -1201,7 +1202,7 @@ public class ExpressionCodegen extends JetVisitor {
             v.load(0, JetTypeMapper.jetImplementationType(contextClass));
         }
         else if (contextKind == OwnerKind.DELEGATING_IMPLEMENTATION) {
-            v.getfield(JetTypeMapper.jvmName(contextClass, contextKind), "$this", JetTypeMapper.jetInterfaceType(contextClass).getDescriptor());
+            v.getfield(typeMapper.jvmName(contextClass, contextKind), "$this", JetTypeMapper.jetInterfaceType(contextClass).getDescriptor());
         }
         else {
             throw new UnsupportedOperationException("Unknown kind: " + contextKind);
@@ -1242,11 +1243,35 @@ public class ExpressionCodegen extends JetVisitor {
     @Override
     public void visitBinaryWithTypeRHSExpression(JetBinaryExpressionWithTypeRHS expression) {
         JetSimpleNameExpression operationSign = expression.getOperationSign();
-        if (operationSign.getReferencedNameElementType() == JetTokens.COLON) {
+        IElementType opToken = operationSign.getReferencedNameElementType();
+        if (opToken == JetTokens.COLON) {
             gen(expression.getLeft());
         }
         else {
-            throw new UnsupportedOperationException("should generate a cast, but don't know how");
+            JetTypeReference typeReference = expression.getRight();
+            JetType jetType = bindingContext.resolveTypeReference(typeReference);
+            if (jetType.getArguments().size() > 0) {
+                throw new UnsupportedOperationException("don't know how to handle type arguments in as/as?");
+            }
+            DeclarationDescriptor descriptor = jetType.getConstructor().getDeclarationDescriptor();
+            if (!(descriptor instanceof ClassDescriptor)) {
+                throw new UnsupportedOperationException("don't know how to handle non-class types in as/as?");
+            }
+            Type type = typeMapper.jvmType((ClassDescriptor) descriptor, OwnerKind.INTERFACE);
+            gen(expression.getLeft(), OBJECT_TYPE);
+            if (opToken == JetTokens.AS_SAFE) {
+                v.dup();
+                v.instanceOf(type);
+                Label isInstance = new Label();
+                v.ifne(isInstance);
+                v.pop();
+                v.aconst(null);
+                v.mark(isInstance);
+                myStack.push(StackValue.onStack(type));
+            }
+            else {
+                throw new UnsupportedOperationException("as not yet implemented");
+            }
         }
     }
 
diff --git a/idea/src/org/jetbrains/jet/codegen/JetTypeMapper.java b/idea/src/org/jetbrains/jet/codegen/JetTypeMapper.java
index c7cb69c4c82..a32aefb4913 100644
--- a/idea/src/org/jetbrains/jet/codegen/JetTypeMapper.java
+++ b/idea/src/org/jetbrains/jet/codegen/JetTypeMapper.java
@@ -32,7 +32,15 @@ public class JetTypeMapper {
         return psiClass.getQualifiedName().replace(".", "/");
     }
 
-    static String jvmName(ClassDescriptor jetClass, OwnerKind kind) {
+    public String jvmName(ClassDescriptor jetClass, OwnerKind kind) {
+        PsiElement declaration = bindingContext.getDeclarationPsiElement(jetClass);
+        if (declaration instanceof PsiClass) {
+            return jvmName((PsiClass) declaration);
+        }
+        return jetJvmName(jetClass, kind);
+    }
+
+    public static String jetJvmName(ClassDescriptor jetClass, OwnerKind kind) {
         if (kind == OwnerKind.INTERFACE) {
             return jvmNameForInterface(jetClass);
         }
@@ -48,6 +56,10 @@ public class JetTypeMapper {
         }
     }
 
+    public Type jvmType(ClassDescriptor jetClass, OwnerKind kind) {
+        return Type.getType("L" + jvmName(jetClass, kind) + ";");
+    }
+
     static Type psiClassType(PsiClass psiClass) {
         return Type.getType("L" + jvmName(psiClass) + ";");
     }
@@ -84,7 +96,7 @@ public class JetTypeMapper {
         return jvmNameForInterface(descriptor) + "$$DImpl";
     }
 
-    static String getOwner(DeclarationDescriptor descriptor, OwnerKind kind) {
+    public String getOwner(DeclarationDescriptor descriptor, OwnerKind kind) {
         String owner;
         if (descriptor.getContainingDeclaration() instanceof NamespaceDescriptor) {
             owner = jvmName((NamespaceDescriptor) descriptor.getContainingDeclaration());
diff --git a/idea/src/org/jetbrains/jet/codegen/PropertyCodegen.java b/idea/src/org/jetbrains/jet/codegen/PropertyCodegen.java
index 3efba079165..dcdead60d80 100644
--- a/idea/src/org/jetbrains/jet/codegen/PropertyCodegen.java
+++ b/idea/src/org/jetbrains/jet/codegen/PropertyCodegen.java
@@ -160,7 +160,7 @@ public class PropertyCodegen {
             }
             else {
                 iv.visitFieldInsn(kind == OwnerKind.NAMESPACE ? Opcodes.GETSTATIC : Opcodes.GETFIELD,
-                        JetTypeMapper.getOwner(propertyDescriptor, kind), propertyDescriptor.getName(),
+                        mapper.getOwner(propertyDescriptor, kind), propertyDescriptor.getName(),
                         type.getDescriptor());
             }
             iv.areturn(type);
@@ -206,7 +206,7 @@ public class PropertyCodegen {
             else {
                 iv.load(paramCode, type);
                 iv.visitFieldInsn(kind == OwnerKind.NAMESPACE ? Opcodes.PUTSTATIC : Opcodes.PUTFIELD,
-                        JetTypeMapper.getOwner(propertyDescriptor, kind), propertyDescriptor.getName(),
+                        mapper.getOwner(propertyDescriptor, kind), propertyDescriptor.getName(),
                         type.getDescriptor());
             }
 
diff --git a/idea/tests/org/jetbrains/jet/codegen/TypeInfoTest.java b/idea/tests/org/jetbrains/jet/codegen/TypeInfoTest.java
index bc316608e86..cd9773c6beb 100644
--- a/idea/tests/org/jetbrains/jet/codegen/TypeInfoTest.java
+++ b/idea/tests/org/jetbrains/jet/codegen/TypeInfoTest.java
@@ -28,5 +28,18 @@ public class TypeInfoTest extends CodegenTestCase {
         TypeInfo typeInfo = (TypeInfo) foo.invoke(null);
         assertNotNull(typeInfo);
     }
+
+    public void testAsSafeOperator() throws Exception {
+        loadText("fun foo(x: Any) = x as? Runnable");
+        System.out.println(generateToText());
+        Method foo = generateFunction();
+        assertNull(foo.invoke(null, new Object()));
+        Runnable r = new Runnable() {
+            @Override
+            public void run() {
+            }
+        };
+        assertSame(r, foo.invoke(null, r));
+    }
 }