diff --git a/idea/src/org/jetbrains/jet/codegen/ClassContext.java b/idea/src/org/jetbrains/jet/codegen/ClassContext.java
index 3ad0f4da7ca..da21e7e8501 100644
--- a/idea/src/org/jetbrains/jet/codegen/ClassContext.java
+++ b/idea/src/org/jetbrains/jet/codegen/ClassContext.java
@@ -36,6 +36,13 @@ public class ClassContext {
         return contextType;
     }
 
+    public String getNamespaceClassName() {
+        if(parentContext != STATIC)
+            return parentContext.getNamespaceClassName();
+
+        return NamespaceCodegen.getJVMClassName(contextType.getName());
+    }
+
     public OwnerKind getContextKind() {
         return contextKind;
     }
@@ -171,7 +178,7 @@ public class ClassContext {
     
     public int getTypeInfoConstantIndex(JetType type) {
         if(parentContext != STATIC)
-            parentContext.getTypeInfoConstantIndex(type);
+            return parentContext.getTypeInfoConstantIndex(type);
         
         if(typeInfoConstants == null)
             typeInfoConstants = new HashMap<JetType, Integer>();
diff --git a/idea/src/org/jetbrains/jet/codegen/ExpressionCodegen.java b/idea/src/org/jetbrains/jet/codegen/ExpressionCodegen.java
index 95588c972c3..d07d89a63d5 100644
--- a/idea/src/org/jetbrains/jet/codegen/ExpressionCodegen.java
+++ b/idea/src/org/jetbrains/jet/codegen/ExpressionCodegen.java
@@ -1947,8 +1947,6 @@ public class ExpressionCodegen extends JetVisitor<StackValue, StackValue> {
             return;
         }
 
-        final Type jvmType = typeMapper.mapType(jetType, OwnerKind.INTERFACE);
-
         if(jetType.getArguments().size() == 0 && !(declarationDescriptor instanceof JavaClassDescriptor)) {
             // TODO: we need some better checks here
             v.getstatic(typeMapper.mapType(jetType, OwnerKind.IMPLEMENTATION).getInternalName(), "$typeInfo", "Ljet/typeinfo/TypeInfo;");
@@ -1957,9 +1955,13 @@ public class ExpressionCodegen extends JetVisitor<StackValue, StackValue> {
         
         boolean hasUnsubstituted = TypeUtils.hasUnsubstitutedTypeParameters(jetType);
         if(!hasUnsubstituted) {
-            context.getTypeInfoConstantIndex(jetType);
+            int typeInfoConstantIndex = context.getTypeInfoConstantIndex(jetType);
+            v.invokestatic(context.getNamespaceClassName(), "$getCachedTypeInfo$" + typeInfoConstantIndex, "()Ljet/typeinfo/TypeInfo;");
+            return;
         }
 
+        final Type jvmType = typeMapper.mapType(jetType, OwnerKind.INTERFACE);
+
         v.aconst(jvmType);
         v.iconst(jetType.isNullable()?1:0);
         List<TypeProjection> arguments = jetType.getArguments();
diff --git a/idea/src/org/jetbrains/jet/codegen/JetTypeMapper.java b/idea/src/org/jetbrains/jet/codegen/JetTypeMapper.java
index 745074db43f..8666e7cd8ba 100644
--- a/idea/src/org/jetbrains/jet/codegen/JetTypeMapper.java
+++ b/idea/src/org/jetbrains/jet/codegen/JetTypeMapper.java
@@ -37,7 +37,7 @@ public class JetTypeMapper {
     public static final Type JL_DOUBLE_TYPE = Type.getObjectType("java/lang/Double");
     public static final Type JL_BOOLEAN_TYPE = Type.getObjectType("java/lang/Boolean");
     public static final Type JL_NUMBER_TYPE = Type.getObjectType("java/lang/Number");
-    public static final Type JL_STRING_BUILDER = Type.getObjectType(ExpressionCodegen.CLASS_STRING_BUILDER);
+    public static final Type JL_STRING_BUILDER = Type.getObjectType("java/lang/StringBuilder");
 
     private final JetStandardLibrary standardLibrary;
     private final BindingContext bindingContext;
diff --git a/idea/src/org/jetbrains/jet/codegen/NamespaceCodegen.java b/idea/src/org/jetbrains/jet/codegen/NamespaceCodegen.java
index 7f0b3c961a0..b5e599721b4 100644
--- a/idea/src/org/jetbrains/jet/codegen/NamespaceCodegen.java
+++ b/idea/src/org/jetbrains/jet/codegen/NamespaceCodegen.java
@@ -1,20 +1,21 @@
 package org.jetbrains.jet.codegen;
 
 import com.intellij.psi.PsiFile;
+import org.jetbrains.jet.lang.descriptors.DeclarationDescriptor;
 import org.jetbrains.jet.lang.descriptors.PropertyDescriptor;
+import org.jetbrains.jet.lang.descriptors.TypeParameterDescriptor;
 import org.jetbrains.jet.lang.psi.*;
 import org.jetbrains.jet.lang.resolve.BindingContext;
+import org.jetbrains.jet.lang.resolve.java.JavaClassDescriptor;
 import org.jetbrains.jet.lang.types.JetType;
-import org.objectweb.asm.ClassVisitor;
-import org.objectweb.asm.MethodVisitor;
-import org.objectweb.asm.Opcodes;
-import org.objectweb.asm.Type;
+import org.jetbrains.jet.lang.types.TypeProjection;
+import org.jetbrains.jet.lang.types.TypeUtils;
+import org.objectweb.asm.*;
 import org.objectweb.asm.commons.InstructionAdapter;
 
-import java.util.Collections;
-import java.util.HashMap;
-import java.util.HashSet;
-import java.util.Map;
+import java.util.*;
+
+import static org.objectweb.asm.Opcodes.*;
 
 /**
  * @author max
@@ -27,8 +28,8 @@ public class NamespaceCodegen {
         this.v = v;
         this.state = state;
 
-        v.visit(Opcodes.V1_6,
-                Opcodes.ACC_PUBLIC,
+        v.visit(V1_6,
+                ACC_PUBLIC,
                 getJVMClassName(fqName),
                 null,
                 //"jet/lang/Namespace",
@@ -68,18 +69,15 @@ public class NamespaceCodegen {
             }
         }
 
-//        System.out.println("-----------");
-//        for(Map.Entry<JetType,Integer> e : (context.typeInfoConstants != null ? context.typeInfoConstants : Collections.<JetType,Integer>emptyMap()).entrySet()) {
-//            System.out.println(e.getKey() + " -> " + e.getValue());
-//        }
-
-        if (hasNonConstantPropertyInitializers(namespace)) {
+        if (hasNonConstantPropertyInitializers(namespace, context)) {
             generateStaticInitializers(namespace, context);
         }
+
+        generateTypeInfoFields(namespace, context);
     }
 
     private void generateStaticInitializers(JetNamespace namespace, ClassContext context) {
-        MethodVisitor mv = v.visitMethod(Opcodes.ACC_PUBLIC | Opcodes.ACC_STATIC,
+        MethodVisitor mv = v.visitMethod(ACC_PUBLIC | ACC_STATIC,
                 "<clinit>", "()V", null, null);
         mv.visitCode();
 
@@ -96,12 +94,85 @@ public class NamespaceCodegen {
                 }
             }
         }
-        mv.visitInsn(Opcodes.RETURN);
+
+        mv.visitInsn(RETURN);
         mv.visitMaxs(0, 0);
         mv.visitEnd();
     }
 
-    private static boolean hasNonConstantPropertyInitializers(JetNamespace namespace) {
+    private void generateTypeInfoFields(JetNamespace namespace, ClassContext context) {
+        if(context.typeInfoConstants != null) {
+            String jvmClassName = getJVMClassName(namespace.getName());
+            for(Map.Entry<JetType,Integer> e : (context.typeInfoConstants != null ? context.typeInfoConstants : Collections.<JetType,Integer>emptyMap()).entrySet()) {
+                String fieldName = "$typeInfoCache$" + e.getValue();
+                v.visitField(ACC_PRIVATE|ACC_STATIC|ACC_SYNTHETIC, fieldName, "Ljet/typeinfo/TypeInfo;", null, null);
+
+                MethodVisitor mmv = v.visitMethod(ACC_PUBLIC|ACC_STATIC|ACC_SYNTHETIC, "$getCachedTypeInfo$" + e.getValue(), "()Ljet/typeinfo/TypeInfo;", null, null);
+                InstructionAdapterEx v = new InstructionAdapterEx(mmv);
+                v.visitFieldInsn(GETSTATIC, jvmClassName, fieldName, "Ljet/typeinfo/TypeInfo;");
+                v.visitInsn(DUP);
+                Label end = new Label();
+                v.visitJumpInsn(IFNONNULL, end);
+
+                v.pop();
+                generateTypeInfo(context, v, e.getKey(), state.getTypeMapper(), e.getKey());
+                v.dup();
+
+                v.visitFieldInsn(PUTSTATIC, jvmClassName, fieldName, "Ljet/typeinfo/TypeInfo;");
+                v.visitLabel(end);
+                v.visitInsn(ARETURN);
+                v.visitMaxs(0, 0);
+                v.visitEnd();
+            }
+        }
+    }
+
+    private void generateTypeInfo(ClassContext context, InstructionAdapterEx v, JetType jetType, JetTypeMapper typeMapper, JetType root) {
+        String knownTypeInfo = typeMapper.isKnownTypeInfo(jetType);
+        if(knownTypeInfo != null) {
+            v.getstatic("jet/typeinfo/TypeInfo", knownTypeInfo, "Ljet/typeinfo/TypeInfo;");
+            return;
+        }
+
+        DeclarationDescriptor declarationDescriptor = jetType.getConstructor().getDeclarationDescriptor();
+        if(!jetType.equals(root) && jetType.getArguments().size() == 0 && !(declarationDescriptor instanceof JavaClassDescriptor)) {
+            // TODO: we need some better checks here
+            v.getstatic(typeMapper.mapType(jetType, OwnerKind.IMPLEMENTATION).getInternalName(), "$typeInfo", "Ljet/typeinfo/TypeInfo;");
+            return;
+        }
+
+        boolean hasUnsubstituted = TypeUtils.hasUnsubstitutedTypeParameters(jetType);
+        if(!jetType.equals(root) && !hasUnsubstituted) {
+            int typeInfoConstantIndex = context.getTypeInfoConstantIndex(jetType);
+            v.invokestatic(context.getNamespaceClassName(), "$getCachedTypeInfo$" + typeInfoConstantIndex, "()Ljet/typeinfo/TypeInfo;");
+            return;
+        }
+
+        final Type jvmType = typeMapper.mapType(jetType, OwnerKind.INTERFACE);
+
+        v.aconst(jvmType);
+        v.iconst(jetType.isNullable() ? 1 : 0);
+        List<TypeProjection> arguments = jetType.getArguments();
+        if (arguments.size() > 0) {
+            v.iconst(arguments.size());
+            v.newarray(JetTypeMapper.TYPE_TYPEINFOPROJECTION);
+
+            for (int i = 0, argumentsSize = arguments.size(); i < argumentsSize; i++) {
+                TypeProjection argument = arguments.get(i);
+                v.dup();
+                v.iconst(i);
+                generateTypeInfo(context, v, argument.getType(), typeMapper, root);
+                ExpressionCodegen.genTypeInfoToProjection(v, argument.getProjectionKind());
+                v.astore(JetTypeMapper.TYPE_OBJECT);
+            }
+            v.invokestatic("jet/typeinfo/TypeInfo", "getTypeInfo", "(Ljava/lang/Class;Z[Ljet/typeinfo/TypeInfoProjection;)Ljet/typeinfo/TypeInfo;");
+        }
+        else {
+            v.invokestatic("jet/typeinfo/TypeInfo", "getTypeInfo", "(Ljava/lang/Class;Z)Ljet/typeinfo/TypeInfo;");
+        }
+    }
+
+    private static boolean hasNonConstantPropertyInitializers(JetNamespace namespace, ClassContext context) {
         for (JetDeclaration declaration : namespace.getDeclarations()) {
             if (declaration instanceof JetProperty) {
                 final JetExpression initializer = ((JetProperty) declaration).getInitializer();
diff --git a/idea/src/org/jetbrains/jet/lang/types/JetTypeImpl.java b/idea/src/org/jetbrains/jet/lang/types/JetTypeImpl.java
index 4d7945db4c4..c5371ba11bb 100644
--- a/idea/src/org/jetbrains/jet/lang/types/JetTypeImpl.java
+++ b/idea/src/org/jetbrains/jet/lang/types/JetTypeImpl.java
@@ -96,7 +96,7 @@ public final class JetTypeImpl extends AnnotatedImpl implements JetType {
         JetTypeImpl type = (JetTypeImpl) o;
 
         // TODO
-        return equalTypes(this, type, EMPTY_AXIOMS);
+        return nullable == type.nullable && equalTypes(this, type, EMPTY_AXIOMS);
 //        if (nullable != type.nullable) return false;
 //        if (arguments != null ? !arguments.equals(type.arguments) : type.arguments != null) return false;
 //        if (constructor != null ? !constructor.equals(type.constructor) : type.constructor != null) return false;
diff --git a/idea/testData/codegen/regressions/kt259.jet b/idea/testData/codegen/regressions/kt259.jet
index bf6ac4b0fe1..dada6e9c2cd 100644
--- a/idea/testData/codegen/regressions/kt259.jet
+++ b/idea/testData/codegen/regressions/kt259.jet
@@ -8,52 +8,143 @@ class B<T>() {
 fun t1() : Boolean {
     val a = A()
     if(a !is A)   return false
+    return true
+}
+
+fun t2() : Boolean {
+    val a = A()
     if(a !is A?)   return false
+    return true
+}
+
+fun t3() : Boolean {
+    val a = A()
     if(null !is A?)   return false
     return true
 }
 
-fun t2 () : Boolean {
+fun t4 () : Boolean {
     val b = B<String>()
     if(b !is B<String>)   return false
+    return true
+}
+
+fun t5 () : Boolean {
+    val b = B<String>()
     if(b !is B<String>?)  return false
+    return true
+}
+
+fun t6 () : Boolean {
     if(null !is B<String>?)  return false
+    return true
+}
 
-    val v = b as B<String>   //ok
-    val u = b as B<String>?  //TypeCastException
+fun t7 () : Boolean {
+    val b = B<String>()
+    if(!b.isT("aaa")) return false
+    return true
+}
 
+fun t8 () : Boolean {
+    val b = B<String>()
+    if(b.isT(10))     return false
+    return true
+}
+
+fun t9 () : Boolean {
+    val b = B<String>()
+    if(b.isT(null))   return false
+    return true
+}
+
+fun t10 () : Boolean {
+    val d = B<String?>()
+    if(!d.isT("aaa")) return false
+    return true
+}
+fun t11 () : Boolean {
+    val d = B<String?>()
+    if(d.isT(10))     return false
+    return true
+}
+
+fun t12 () : Boolean {
+    val d = B<String?>()
+    if(!d.isT(null))  return false
+    return true
+}
+
+fun t13 () : Boolean {
+    val f = B<java.lang.String?>()
+    if(!f.isT("aaa")) return false
+    return true
+}
+
+fun t14 () : Boolean {
+    val f = B<java.lang.String?>()
+    if(f.isT(10))     return false
+    return true
+}
+
+fun t15 () : Boolean {
+    val f = B<java.lang.String?>()
+    if(!f.isT(null))  return false
+    return true
+}
+
+fun t16 () : Boolean {
+    val c = B<Int>()
+    if(c.isT("aaa")) return false
+    return true
+}
+
+fun t17 () : Boolean {
+    val c = B<Int>()
+    if(!c.isT(10))   return false
+    return true
+}
+
+fun t18 () : Boolean {
+    val c = B<Int>()
+    if(c.isT(null)) return false
+    return true
+}
+
+fun t19 () : Boolean {
+    val e = B<Int?>()
+    if(e.isT("aaa")) return false
+    return true
+}
+
+fun t20 () : Boolean {
+    val e = B<Int?>()
+    if(!e.isT(10))   return false
+    return true
+}
+
+fun t21 () : Boolean {
+    val e = B<Int?>()
+    if(!e.isT(null)) return false
+    return true
+}
+
+fun t22 () : Boolean {
+    val b = B<String>()
     val w : B<String>? = b as B<String>   //ok
     val x = w as B<String>?  //TypeCastException
     return true
 }
 
-fun t3 () : Boolean {
+fun t23 () : Boolean {
     val b = B<String>()
-    if(!b.isT("aaa")) return false
-
-    if(b.isT(10))     return false
-    if(b.isT(null))   return false
-
-    val d = B<String?>()
-    if(!d.isT("aaa")) return false
-    if(d.isT(10))     return false
-    if(!d.isT(null))  return false
-
-    val f = B<java.lang.String?>()
-    if(!f.isT("aaa")) return false
-    if(f.isT(10))     return false
-    if(!f.isT(null))  return false
-
-    val c = B<Int>()
-    if(c.isT("aaa")) return false
-    if(!c.isT(10))   return false
-    if(c.isT(null)) return false
-
-    val e = B<Int?>()
-    if(e.isT("aaa")) return false
-    if(!e.isT(10))   return false
-    if(!e.isT(null)) return false
+    val v = b as B<String>   //ok
+    return true
+}
 
+fun t24 () : Boolean {
+    val b = B<String>()
+    val u = b as B<String>?  //TypeCastException
     return true
 }
 
@@ -67,5 +158,68 @@ fun box() : String {
     if(!t3()) {
         return "t3 failed"
     }
-    return "OK"
+    if(!t4()) {
+         return "t4 failed"
+     }
+     if(!t5()) {
+         return "t5 failed"
+     }
+     if(!t6()) {
+         return "t6 failed"
+     }
+     if(!t7()) {
+         return "t7 failed"
+     }
+    if(!t8()) {
+        return "t8 failed"
+    }
+    if(!t9()) {
+        return "t9 failed"
+    }
+    if(!t10()) {
+        return "t10 failed"
+    }
+    if(!t11()) {
+         return "t11 failed"
+     }
+     if(!t12()) {
+         return "t12 failed"
+     }
+     if(!t13()) {
+         return "t13 failed"
+     }
+     if(!t14()) {
+         return "t14 failed"
+     }
+    if(!t15()) {
+        return "t15 failed"
+    }
+    if(!t16()) {
+        return "t16 failed"
+    }
+    if(!t17()) {
+        return "t17 failed"
+    }
+    if(!t18()) {
+         return "t18 failed"
+     }
+     if(!t19()) {
+         return "t19 failed"
+     }
+     if(!t20()) {
+         return "t10 failed"
+     }
+     if(!t21()) {
+         return "t21 failed"
+     }
+     if(!t22()) {
+         return "t22 failed"
+     }
+     if(!t23()) {
+         return "t23 failed"
+     }
+     if(!t24()) {
+         return "t24 failed"
+     }
+     return "OK"
 }
\ No newline at end of file
diff --git a/idea/tests/org/jetbrains/jet/codegen/PatternMatchingTest.java b/idea/tests/org/jetbrains/jet/codegen/PatternMatchingTest.java
index c82f9a4847d..60337ed4ff2 100644
--- a/idea/tests/org/jetbrains/jet/codegen/PatternMatchingTest.java
+++ b/idea/tests/org/jetbrains/jet/codegen/PatternMatchingTest.java
@@ -49,8 +49,8 @@ public class PatternMatchingTest extends CodegenTestCase {
 
     public void testIs() throws Exception {
         loadFile();
-        blackBox();
         System.out.println(generateToText());
+        blackBox();
     }
 
     public void testRange() throws Exception {