diff --git a/compiler/backend/src/org/jetbrains/jet/codegen/AsmUtil.java b/compiler/backend/src/org/jetbrains/jet/codegen/AsmUtil.java
index caa53b937d2..387cdc6d025 100644
--- a/compiler/backend/src/org/jetbrains/jet/codegen/AsmUtil.java
+++ b/compiler/backend/src/org/jetbrains/jet/codegen/AsmUtil.java
@@ -37,7 +37,6 @@ import org.jetbrains.jet.lang.resolve.java.AsmTypeConstants;
 import org.jetbrains.jet.lang.resolve.java.JavaDescriptorResolver;
 import org.jetbrains.jet.lang.resolve.java.JvmAbi;
 import org.jetbrains.jet.lang.resolve.java.JvmPrimitiveType;
-import org.jetbrains.jet.lang.resolve.scopes.receivers.ClassReceiver;
 import org.jetbrains.jet.lang.types.JetType;
 import org.jetbrains.jet.lang.types.lang.KotlinBuiltIns;
 import org.jetbrains.jet.lexer.JetTokens;
@@ -47,8 +46,7 @@ import java.util.Map;
 import java.util.Set;
 
 import static org.jetbrains.asm4.Opcodes.*;
-import static org.jetbrains.jet.codegen.CodegenUtil.isInterface;
-import static org.jetbrains.jet.codegen.CodegenUtil.isNullableType;
+import static org.jetbrains.jet.codegen.CodegenUtil.*;
 import static org.jetbrains.jet.lang.resolve.DescriptorUtils.isClassObject;
 import static org.jetbrains.jet.lang.resolve.java.AsmTypeConstants.JAVA_STRING_TYPE;
 
@@ -269,6 +267,16 @@ public class AsmUtil {
         return null;
     }
 
+    @NotNull
+    public static Type getTraitImplThisParameterType(@NotNull ClassDescriptor traitDescriptor, @NotNull JetTypeMapper typeMapper) {
+        JetType jetType = getSuperClass(traitDescriptor);
+        Type type = typeMapper.mapType(jetType);
+        if (type.getInternalName().equals("java/lang/Object")) {
+            return typeMapper.mapType(traitDescriptor.getDefaultType());
+        }
+        return type;
+    }
+
     private static Type stringValueOfOrStringBuilderAppendType(Type type) {
         int sort = type.getSort();
         return sort == Type.OBJECT || sort == Type.ARRAY
diff --git a/compiler/backend/src/org/jetbrains/jet/codegen/ImplementationBodyCodegen.java b/compiler/backend/src/org/jetbrains/jet/codegen/ImplementationBodyCodegen.java
index 9cad090f9d6..fbc84cf1d44 100644
--- a/compiler/backend/src/org/jetbrains/jet/codegen/ImplementationBodyCodegen.java
+++ b/compiler/backend/src/org/jetbrains/jet/codegen/ImplementationBodyCodegen.java
@@ -64,7 +64,6 @@ import static org.jetbrains.jet.codegen.AsmUtil.*;
 import static org.jetbrains.jet.codegen.CodegenUtil.*;
 import static org.jetbrains.jet.codegen.binding.CodegenBinding.*;
 import static org.jetbrains.jet.lang.resolve.BindingContextUtils.callableDescriptorToDeclaration;
-import static org.jetbrains.jet.lang.resolve.BindingContextUtils.descriptorToDeclaration;
 import static org.jetbrains.jet.lang.resolve.DescriptorUtils.*;
 import static org.jetbrains.jet.lang.resolve.java.AsmTypeConstants.JAVA_STRING_TYPE;
 import static org.jetbrains.jet.lang.resolve.java.AsmTypeConstants.OBJECT_TYPE;
@@ -1431,12 +1430,7 @@ public class ImplementationBodyCodegen extends ClassBodyCodegen {
                         reg += argTypes[i].getSize();
                     }
 
-                    JetType jetType = CodegenUtil.getSuperClass(declaration);
-                    Type type = typeMapper.mapType(jetType, JetTypeMapperMode.IMPL);
-                    if (type.getInternalName().equals("java/lang/Object")) {
-                        jetType = declaration.getDefaultType();
-                        type = typeMapper.mapType(jetType, JetTypeMapperMode.IMPL);
-                    }
+                    Type type = getTraitImplThisParameterType(declaration, typeMapper);
 
                     String fdescriptor = functionOriginal.getDescriptor().replace("(", "(" + type.getDescriptor());
                     Type type1 =
diff --git a/compiler/backend/src/org/jetbrains/jet/codegen/state/JetTypeMapper.java b/compiler/backend/src/org/jetbrains/jet/codegen/state/JetTypeMapper.java
index 079194f1435..cfa747615ca 100644
--- a/compiler/backend/src/org/jetbrains/jet/codegen/state/JetTypeMapper.java
+++ b/compiler/backend/src/org/jetbrains/jet/codegen/state/JetTypeMapper.java
@@ -46,6 +46,7 @@ import java.util.Map;
 
 import static org.jetbrains.asm4.Opcodes.*;
 import static org.jetbrains.jet.codegen.AsmUtil.boxType;
+import static org.jetbrains.jet.codegen.AsmUtil.getTraitImplThisParameterType;
 import static org.jetbrains.jet.codegen.CodegenUtil.*;
 import static org.jetbrains.jet.codegen.binding.CodegenBinding.*;
 import static org.jetbrains.jet.lang.resolve.BindingContextUtils.descriptorToDeclaration;
@@ -547,10 +548,11 @@ public class JetTypeMapper extends BindingTraceAware {
                 thisClass, receiverParameterType, null);
     }
 
-    private static boolean isAccessor(FunctionDescriptor functionDescriptor) {
-        return functionDescriptor instanceof AccessorForFunctionDescriptor ||
-               functionDescriptor instanceof AccessorForPropertyDescriptor.Getter ||
-               functionDescriptor instanceof AccessorForPropertyDescriptor.Setter;
+    private static boolean isAccessor(@NotNull CallableMemberDescriptor descriptor) {
+        return descriptor instanceof AccessorForFunctionDescriptor ||
+               descriptor instanceof AccessorForPropertyDescriptor ||
+               descriptor instanceof AccessorForPropertyDescriptor.Getter ||
+               descriptor instanceof AccessorForPropertyDescriptor.Setter;
     }
 
     @NotNull
@@ -566,7 +568,6 @@ public class JetTypeMapper extends BindingTraceAware {
     }
 
     private JvmMethodSignature mapSignature(FunctionDescriptor f, boolean needGenericSignature, OwnerKind kind) {
-
         if (kind == OwnerKind.TRAIT_IMPL) {
             needGenericSignature = false;
         }
@@ -575,35 +576,11 @@ public class JetTypeMapper extends BindingTraceAware {
 
         writeFormalTypeParameters(f.getTypeParameters(), signatureVisitor);
 
-        JetType receiverType = DescriptorUtils.getReceiverParameterType(f.getReceiverParameter());
-        List<ValueParameterDescriptor> parameters = f.getValueParameters();
-
         signatureVisitor.writeParametersStart();
+        writeThisIfNeeded(f, kind, signatureVisitor);
+        writeReceiverIfNeeded(f.getReceiverParameter(), signatureVisitor);
 
-        if (kind == OwnerKind.TRAIT_IMPL) {
-            ClassDescriptor containingDeclaration = (ClassDescriptor) f.getContainingDeclaration();
-            JetType jetType = CodegenUtil.getSuperClass(containingDeclaration);
-            Type type = mapType(jetType);
-            if (type.getInternalName().equals("java/lang/Object")) {
-                jetType = containingDeclaration.getDefaultType();
-                type = mapType(jetType);
-            }
-
-            signatureVisitor.writeParameterType(JvmMethodParameterKind.THIS);
-            signatureVisitor.writeAsmType(type, jetType.isNullable());
-            signatureVisitor.writeParameterTypeEnd();
-        }
-        else {
-            writeThisForAccessorIfNeeded(f, signatureVisitor);
-        }
-
-        if (receiverType != null) {
-            signatureVisitor.writeParameterType(JvmMethodParameterKind.RECEIVER);
-            mapType(receiverType, signatureVisitor, JetTypeMapperMode.VALUE);
-            signatureVisitor.writeParameterTypeEnd();
-        }
-
-        for (ValueParameterDescriptor parameter : parameters) {
+        for (ValueParameterDescriptor parameter : f.getValueParameters()) {
             writeParameter(signatureVisitor, parameter.getType());
         }
 
@@ -622,10 +599,28 @@ public class JetTypeMapper extends BindingTraceAware {
         return signatureVisitor.makeJvmMethodSignature(f.getName().getName());
     }
 
-    private void writeThisForAccessorIfNeeded(FunctionDescriptor f, BothSignatureWriter signatureVisitor) {
-        if (isAccessor(f) && f.getExpectedThisObject() != null) {
+    private void writeThisIfNeeded(
+            @NotNull CallableMemberDescriptor descriptor,
+            @NotNull OwnerKind kind,
+            @NotNull BothSignatureWriter signatureVisitor
+    ) {
+        if (kind == OwnerKind.TRAIT_IMPL) {
+            ClassDescriptor containingDeclaration = (ClassDescriptor) descriptor.getContainingDeclaration();
+            Type type = getTraitImplThisParameterType(containingDeclaration, this);
+
             signatureVisitor.writeParameterType(JvmMethodParameterKind.THIS);
-            mapType(((ClassifierDescriptor) f.getContainingDeclaration()).getDefaultType(), signatureVisitor, JetTypeMapperMode.VALUE);
+            signatureVisitor.writeAsmType(type, false);
+            signatureVisitor.writeParameterTypeEnd();
+        }
+        else {
+            writeThisForAccessorIfNeeded(descriptor, signatureVisitor);
+        }
+    }
+
+    private void writeThisForAccessorIfNeeded(@NotNull CallableMemberDescriptor descriptor, @NotNull BothSignatureWriter signatureVisitor) {
+        if (isAccessor(descriptor) && descriptor.getExpectedThisObject() != null) {
+            signatureVisitor.writeParameterType(JvmMethodParameterKind.THIS);
+            mapType(((ClassifierDescriptor) descriptor.getContainingDeclaration()).getDefaultType(), signatureVisitor, JetTypeMapperMode.VALUE);
             signatureVisitor.writeParameterTypeEnd();
         }
     }