diff --git a/compiler/backend/src/org/jetbrains/jet/codegen/signature/JvmMethodParameterSignature.java b/compiler/backend/src/org/jetbrains/jet/codegen/signature/JvmMethodParameterSignature.java
index 6c01644ec47..17226b27d83 100644
--- a/compiler/backend/src/org/jetbrains/jet/codegen/signature/JvmMethodParameterSignature.java
+++ b/compiler/backend/src/org/jetbrains/jet/codegen/signature/JvmMethodParameterSignature.java
@@ -19,13 +19,11 @@ package org.jetbrains.jet.codegen.signature;
 import org.jetbrains.annotations.NotNull;
 import org.jetbrains.asm4.Type;
 
-public class JvmMethodParameterSignature {
-    @NotNull
+public final class JvmMethodParameterSignature {
     private final Type asmType;
-    @NotNull
     private final JvmMethodParameterKind kind;
 
-    public JvmMethodParameterSignature(@NotNull Type asmType, @NotNull JvmMethodParameterKind kind) {
+    JvmMethodParameterSignature(@NotNull Type asmType, @NotNull JvmMethodParameterKind kind) {
         this.asmType = asmType;
         this.kind = kind;
     }
@@ -39,4 +37,23 @@ public class JvmMethodParameterSignature {
     public JvmMethodParameterKind getKind() {
         return kind;
     }
+
+    @Override
+    public boolean equals(Object o) {
+        if (this == o) return true;
+        if (!(o instanceof JvmMethodParameterSignature)) return false;
+
+        JvmMethodParameterSignature that = (JvmMethodParameterSignature) o;
+        return asmType.equals(that.asmType) && kind == that.kind;
+    }
+
+    @Override
+    public int hashCode() {
+        return 31 * asmType.hashCode() + kind.hashCode();
+    }
+
+    @Override
+    public String toString() {
+        return kind + " " + asmType;
+    }
 }
diff --git a/compiler/backend/src/org/jetbrains/jet/codegen/signature/JvmMethodSignature.java b/compiler/backend/src/org/jetbrains/jet/codegen/signature/JvmMethodSignature.java
index f41c2bef76e..a3e070dbb62 100644
--- a/compiler/backend/src/org/jetbrains/jet/codegen/signature/JvmMethodSignature.java
+++ b/compiler/backend/src/org/jetbrains/jet/codegen/signature/JvmMethodSignature.java
@@ -28,7 +28,7 @@ public class JvmMethodSignature {
     private final String genericsSignature;
     private final List<JvmMethodParameterSignature> valueParameters;
 
-    protected JvmMethodSignature(
+    JvmMethodSignature(
             @NotNull Method asmMethod,
             @Nullable String genericsSignature,
             @NotNull List<JvmMethodParameterSignature> valueParameters
@@ -65,6 +65,26 @@ public class JvmMethodSignature {
                new JvmMethodSignature(new Method(newName, asmMethod.getDescriptor()), genericsSignature, valueParameters);
     }
 
+    @Override
+    public boolean equals(Object o) {
+        if (this == o) return true;
+        if (!(o instanceof JvmMethodSignature)) return false;
+
+        JvmMethodSignature that = (JvmMethodSignature) o;
+
+        return asmMethod.equals(that.asmMethod) &&
+               (genericsSignature == null ? that.genericsSignature == null : genericsSignature.equals(that.genericsSignature)) &&
+               valueParameters.equals(that.valueParameters);
+    }
+
+    @Override
+    public int hashCode() {
+        int result = asmMethod.hashCode();
+        result = 31 * result + (genericsSignature != null ? genericsSignature.hashCode() : 0);
+        result = 31 * result + valueParameters.hashCode();
+        return result;
+    }
+
     @Override
     public String toString() {
         return asmMethod.toString();