diff --git a/compiler/frontend/serialization/src/org/jetbrains/jet/descriptors/serialization/DescriptorDeserializer.java b/compiler/frontend/serialization/src/org/jetbrains/jet/descriptors/serialization/DescriptorDeserializer.java
index 61df151c942..e7a56f5993b 100644
--- a/compiler/frontend/serialization/src/org/jetbrains/jet/descriptors/serialization/DescriptorDeserializer.java
+++ b/compiler/frontend/serialization/src/org/jetbrains/jet/descriptors/serialization/DescriptorDeserializer.java
@@ -219,7 +219,7 @@ public class DescriptorDeserializer {
     @NotNull
     private CallableMemberDescriptor loadFunction(@NotNull Callable proto) {
         int flags = proto.getFlags();
-        DeserializedSimpleFunctionDescriptor function = new DeserializedSimpleFunctionDescriptor(
+        DeserializedSimpleFunctionDescriptor function = DeserializedSimpleFunctionDescriptor.create(
                 containingDeclaration, proto,
                 deserializers,
                 nameResolver
diff --git a/compiler/frontend/serialization/src/org/jetbrains/jet/descriptors/serialization/descriptors/DeserializedSimpleFunctionDescriptor.java b/compiler/frontend/serialization/src/org/jetbrains/jet/descriptors/serialization/descriptors/DeserializedSimpleFunctionDescriptor.java
index 8e03fb2282c..d5624e05b21 100644
--- a/compiler/frontend/serialization/src/org/jetbrains/jet/descriptors/serialization/descriptors/DeserializedSimpleFunctionDescriptor.java
+++ b/compiler/frontend/serialization/src/org/jetbrains/jet/descriptors/serialization/descriptors/DeserializedSimpleFunctionDescriptor.java
@@ -17,6 +17,7 @@
 package org.jetbrains.jet.descriptors.serialization.descriptors;
 
 import org.jetbrains.annotations.NotNull;
+import org.jetbrains.annotations.Nullable;
 import org.jetbrains.jet.descriptors.serialization.DescriptorDeserializer;
 import org.jetbrains.jet.descriptors.serialization.Flags;
 import org.jetbrains.jet.descriptors.serialization.NameResolver;
@@ -35,20 +36,7 @@ public class DeserializedSimpleFunctionDescriptor extends SimpleFunctionDescript
 
     private DeserializedSimpleFunctionDescriptor(
             @NotNull DeclarationDescriptor containingDeclaration,
-            @NotNull Annotations annotations,
-            @NotNull Name name,
-            @NotNull Kind kind,
-            @NotNull ProtoBuf.Callable functionProto,
-            @NotNull NameResolver nameResolver
-    ) {
-        super(containingDeclaration, annotations, name, kind);
-        this.functionProto = functionProto;
-        this.nameResolver = nameResolver;
-    }
-
-    private DeserializedSimpleFunctionDescriptor(
-            @NotNull DeclarationDescriptor containingDeclaration,
-            @NotNull SimpleFunctionDescriptor original,
+            @Nullable SimpleFunctionDescriptor original,
             @NotNull Annotations annotations,
             @NotNull Name name,
             @NotNull Kind kind,
@@ -59,45 +47,17 @@ public class DeserializedSimpleFunctionDescriptor extends SimpleFunctionDescript
         this.nameResolver = nameResolver;
     }
 
-    public DeserializedSimpleFunctionDescriptor(
-            @NotNull DeclarationDescriptor containingDeclaration,
-            @NotNull ProtoBuf.Callable functionProto,
-            @NotNull Deserializers deserializers,
-            @NotNull NameResolver nameResolver
-    ) {
-        this(containingDeclaration,
-             DescriptorDeserializer.getAnnotations(containingDeclaration, functionProto, functionProto.getFlags(),
-                                                   Deserializers.AnnotatedCallableKind.FUNCTION, deserializers.getAnnotationDeserializer(),
-                                                   nameResolver),
-             nameResolver.getName(functionProto.getName()),
-             DescriptorDeserializer.memberKind(Flags.MEMBER_KIND.get(functionProto.getFlags())),
-             functionProto,
-             nameResolver);
-    }
-
     @Override
     protected FunctionDescriptorImpl createSubstitutedCopy(DeclarationDescriptor newOwner, boolean preserveOriginal, Kind kind) {
-        if (preserveOriginal) {
-            return new DeserializedSimpleFunctionDescriptor(
-                    newOwner,
-                    getOriginal(),
-                    getAnnotations(),
-                    getName(),
-                    kind,
-                    functionProto,
-                    nameResolver
-            );
-        }
-        else {
-            return new DeserializedSimpleFunctionDescriptor(
-                    newOwner,
-                    getAnnotations(),
-                    getName(),
-                    kind,
-                    functionProto,
-                    nameResolver
-            );
-        }
+        return new DeserializedSimpleFunctionDescriptor(
+                newOwner,
+                preserveOriginal ? getOriginal() : null,
+                getAnnotations(),
+                getName(),
+                kind,
+                functionProto,
+                nameResolver
+        );
     }
 
     @NotNull
@@ -113,4 +73,24 @@ public class DeserializedSimpleFunctionDescriptor extends SimpleFunctionDescript
     public NameResolver getNameResolver() {
         return nameResolver;
     }
+
+    public static DeserializedSimpleFunctionDescriptor create(
+            @NotNull DeclarationDescriptor containingDeclaration,
+            @NotNull ProtoBuf.Callable functionProto,
+            @NotNull Deserializers deserializers,
+            @NotNull NameResolver nameResolver
+    ) {
+        Annotations annotations = DescriptorDeserializer.getAnnotations(containingDeclaration, functionProto, functionProto.getFlags(),
+                                                                        Deserializers.AnnotatedCallableKind.FUNCTION,
+                                                                        deserializers.getAnnotationDeserializer(),
+                                                                        nameResolver);
+        return new DeserializedSimpleFunctionDescriptor(
+                containingDeclaration,
+                null,
+                annotations,
+                nameResolver.getName(functionProto.getName()),
+                DescriptorDeserializer.memberKind(Flags.MEMBER_KIND.get(functionProto.getFlags())),
+                functionProto,
+                nameResolver);
+    }
 }
diff --git a/core/descriptors/src/org/jetbrains/jet/lang/descriptors/impl/ConstructorDescriptorImpl.java b/core/descriptors/src/org/jetbrains/jet/lang/descriptors/impl/ConstructorDescriptorImpl.java
index 50729d6b84c..2c87142e251 100644
--- a/core/descriptors/src/org/jetbrains/jet/lang/descriptors/impl/ConstructorDescriptorImpl.java
+++ b/core/descriptors/src/org/jetbrains/jet/lang/descriptors/impl/ConstructorDescriptorImpl.java
@@ -40,7 +40,7 @@ public class ConstructorDescriptorImpl extends FunctionDescriptorImpl implements
     }
 
     public ConstructorDescriptorImpl(@NotNull ClassDescriptor containingDeclaration, @NotNull Annotations annotations, boolean isPrimary, Kind kind) {
-        super(containingDeclaration, annotations, NAME, kind);
+        super(containingDeclaration, null, annotations, NAME, kind);
         this.isPrimary = isPrimary;
     }
 
diff --git a/core/descriptors/src/org/jetbrains/jet/lang/descriptors/impl/FunctionDescriptorImpl.java b/core/descriptors/src/org/jetbrains/jet/lang/descriptors/impl/FunctionDescriptorImpl.java
index ae6a5baf99f..7dead86d131 100644
--- a/core/descriptors/src/org/jetbrains/jet/lang/descriptors/impl/FunctionDescriptorImpl.java
+++ b/core/descriptors/src/org/jetbrains/jet/lang/descriptors/impl/FunctionDescriptorImpl.java
@@ -50,22 +50,12 @@ public abstract class FunctionDescriptorImpl extends DeclarationDescriptorNonRoo
 
     protected FunctionDescriptorImpl(
             @NotNull DeclarationDescriptor containingDeclaration,
+            @Nullable FunctionDescriptor original,
             @NotNull Annotations annotations,
             @NotNull Name name,
             @NotNull Kind kind) {
         super(containingDeclaration, annotations, name);
-        this.original = this;
-        this.kind = kind;
-    }
-
-    protected FunctionDescriptorImpl(
-            @NotNull DeclarationDescriptor containingDeclaration,
-            @NotNull FunctionDescriptor original,
-            @NotNull Annotations annotations,
-            @NotNull Name name,
-            @NotNull Kind kind) {
-        super(containingDeclaration, annotations, name);
-        this.original = original;
+        this.original = original == null ? this : original;
         this.kind = kind;
     }
 
diff --git a/core/descriptors/src/org/jetbrains/jet/lang/descriptors/impl/ScriptCodeDescriptor.java b/core/descriptors/src/org/jetbrains/jet/lang/descriptors/impl/ScriptCodeDescriptor.java
index f459259b551..d146079fa64 100644
--- a/core/descriptors/src/org/jetbrains/jet/lang/descriptors/impl/ScriptCodeDescriptor.java
+++ b/core/descriptors/src/org/jetbrains/jet/lang/descriptors/impl/ScriptCodeDescriptor.java
@@ -28,7 +28,7 @@ import java.util.List;
 public class ScriptCodeDescriptor extends FunctionDescriptorImpl {
 
     public ScriptCodeDescriptor(@NotNull ScriptDescriptor containingDeclaration) {
-        super(containingDeclaration, Annotations.EMPTY, Name.special("<script-code>"), Kind.DECLARATION);
+        super(containingDeclaration, null, Annotations.EMPTY, Name.special("<script-code>"), Kind.DECLARATION);
         setVisibility(Visibilities.LOCAL);
     }
 
diff --git a/core/descriptors/src/org/jetbrains/jet/lang/descriptors/impl/SimpleFunctionDescriptorImpl.java b/core/descriptors/src/org/jetbrains/jet/lang/descriptors/impl/SimpleFunctionDescriptorImpl.java
index b12e8b52223..91ac0311cac 100644
--- a/core/descriptors/src/org/jetbrains/jet/lang/descriptors/impl/SimpleFunctionDescriptorImpl.java
+++ b/core/descriptors/src/org/jetbrains/jet/lang/descriptors/impl/SimpleFunctionDescriptorImpl.java
@@ -38,12 +38,12 @@ public class SimpleFunctionDescriptorImpl extends FunctionDescriptorImpl impleme
             @NotNull Name name,
             @NotNull Kind kind
     ) {
-        super(containingDeclaration, annotations, name, kind);
+        this(containingDeclaration, null, annotations, name, kind);
     }
 
     protected SimpleFunctionDescriptorImpl(
             @NotNull DeclarationDescriptor containingDeclaration,
-            @NotNull SimpleFunctionDescriptor original,
+            @Nullable SimpleFunctionDescriptor original,
             @NotNull Annotations annotations,
             @NotNull Name name,
             @NotNull Kind kind) {
@@ -76,30 +76,19 @@ public class SimpleFunctionDescriptorImpl extends FunctionDescriptorImpl impleme
 
     @Override
     protected FunctionDescriptorImpl createSubstitutedCopy(DeclarationDescriptor newOwner, boolean preserveOriginal, Kind kind) {
-        if (preserveOriginal) {
-            return new SimpleFunctionDescriptorImpl(
-                    newOwner,
-                    getOriginal(),
-                    // TODO : safeSubstitute
-                    getAnnotations(),
-                    getName(),
-                    kind);
-        }
-        else {
-            return new SimpleFunctionDescriptorImpl(
-                    newOwner,
-                    // TODO : safeSubstitute
-                    getAnnotations(),
-                    getName(),
-                    kind);
-        }
+        return new SimpleFunctionDescriptorImpl(
+                newOwner,
+                preserveOriginal ? getOriginal() : null,
+                // TODO : safeSubstitute
+                getAnnotations(),
+                getName(),
+                kind);
     }
 
     @NotNull
     @Override
     public SimpleFunctionDescriptor copy(DeclarationDescriptor newOwner, Modality modality, Visibility visibility, Kind kind, boolean copyOverrides) {
-        SimpleFunctionDescriptorImpl copy = (SimpleFunctionDescriptorImpl)doSubstitute(TypeSubstitutor.EMPTY, newOwner, modality, visibility, false, copyOverrides, kind);
-        return copy;
+        return (SimpleFunctionDescriptorImpl)doSubstitute(TypeSubstitutor.EMPTY, newOwner, modality, visibility, false, copyOverrides, kind);
     }
 
     @NotNull