diff --git a/compiler/frontend.java/src/org/jetbrains/jet/lang/resolve/java/DescriptorSearchRule.java b/compiler/frontend.java/src/org/jetbrains/jet/lang/resolve/java/DescriptorSearchRule.java
index 494635e7206..f38ef223f58 100644
--- a/compiler/frontend.java/src/org/jetbrains/jet/lang/resolve/java/DescriptorSearchRule.java
+++ b/compiler/frontend.java/src/org/jetbrains/jet/lang/resolve/java/DescriptorSearchRule.java
@@ -16,11 +16,31 @@
 
 package org.jetbrains.jet.lang.resolve.java;
 
+import org.jetbrains.jet.lang.descriptors.DeclarationDescriptor;
+import org.jetbrains.jet.lang.resolve.DescriptorUtils;
+
 /**
  * @author Stepan Koltsov
  */
 public enum DescriptorSearchRule {
-    INCLUDE_KOTLIN,
-    IGNORE_IF_FOUND_IN_KOTLIN,
-    ERROR_IF_FOUND_IN_KOTLIN,
+    INCLUDE_KOTLIN {
+        @Override
+        public <T extends DeclarationDescriptor> T processFoundInKotlin(T foundDescriptor) {
+            return foundDescriptor;
+        }
+    },
+    IGNORE_IF_FOUND_IN_KOTLIN {
+        @Override
+        public <T extends DeclarationDescriptor> T processFoundInKotlin(T foundDescriptor) {
+            return null;
+        }
+    },
+    ERROR_IF_FOUND_IN_KOTLIN {
+        @Override
+        public <T extends DeclarationDescriptor> T processFoundInKotlin(T foundDescriptor) {
+            throw new IllegalStateException(DescriptorUtils.getFQName(foundDescriptor) + " should not be found in Kotlin.");
+        }
+    };
+
+    public abstract <T extends DeclarationDescriptor> T processFoundInKotlin(T foundDescriptor);
 }
diff --git a/compiler/frontend.java/src/org/jetbrains/jet/lang/resolve/java/resolver/ClassResolver.java b/compiler/frontend.java/src/org/jetbrains/jet/lang/resolve/java/resolver/ClassResolver.java
index adc4ac51421..9e3046e802c 100644
--- a/compiler/frontend.java/src/org/jetbrains/jet/lang/resolve/java/resolver/ClassResolver.java
+++ b/compiler/frontend.java/src/org/jetbrains/jet/lang/resolve/java/resolver/ClassResolver.java
@@ -113,18 +113,7 @@ public final class ClassResolver {
         // First, let's check that this is a real Java class, not a Java's view on a Kotlin class:
         ClassDescriptor kotlinClassDescriptor = javaDescriptorResolver.getSemanticServices().getKotlinClassDescriptor(qualifiedName);
         if (kotlinClassDescriptor != null) {
-            if (searchRule == DescriptorSearchRule.ERROR_IF_FOUND_IN_KOTLIN) {
-                throw new IllegalStateException("class must not be found in kotlin: " + qualifiedName);
-            }
-            else if (searchRule == DescriptorSearchRule.IGNORE_IF_FOUND_IN_KOTLIN) {
-                return null;
-            }
-            else if (searchRule == DescriptorSearchRule.INCLUDE_KOTLIN) {
-                return kotlinClassDescriptor;
-            }
-            else {
-                throw new IllegalStateException("unknown searchRule: " + searchRule);
-            }
+            return searchRule.processFoundInKotlin(kotlinClassDescriptor);
         }
 
         // Not let's take a descriptor of a Java class
diff --git a/compiler/frontend.java/src/org/jetbrains/jet/lang/resolve/java/resolver/NamespaceResolver.java b/compiler/frontend.java/src/org/jetbrains/jet/lang/resolve/java/resolver/NamespaceResolver.java
index 126ae33e3ac..c121e0cb944 100644
--- a/compiler/frontend.java/src/org/jetbrains/jet/lang/resolve/java/resolver/NamespaceResolver.java
+++ b/compiler/frontend.java/src/org/jetbrains/jet/lang/resolve/java/resolver/NamespaceResolver.java
@@ -38,11 +38,14 @@ import java.util.Map;
 
 public final class NamespaceResolver {
 
+    @NotNull
     public static final ModuleDescriptor FAKE_ROOT_MODULE = new ModuleDescriptor(JavaDescriptorResolver.JAVA_ROOT);
+    @NotNull
     private final JavaDescriptorResolver javaDescriptorResolver;
+    @NotNull
     private final Map<FqName, ResolverNamespaceData> namespaceDescriptorCacheByFqn = Maps.newHashMap();
 
-    public NamespaceResolver(JavaDescriptorResolver javaDescriptorResolver) {
+    public NamespaceResolver(@NotNull JavaDescriptorResolver javaDescriptorResolver) {
         this.javaDescriptorResolver = javaDescriptorResolver;
     }
 
@@ -52,19 +55,7 @@ public final class NamespaceResolver {
         NamespaceDescriptor kotlinNamespaceDescriptor =
                 javaDescriptorResolver.getSemanticServices().getKotlinNamespaceDescriptor(qualifiedName);
         if (kotlinNamespaceDescriptor != null) {
-            if (searchRule == DescriptorSearchRule.ERROR_IF_FOUND_IN_KOTLIN) {
-                throw new IllegalStateException("class must not be found in kotlin: " + qualifiedName);
-            }
-            else if (searchRule == DescriptorSearchRule.IGNORE_IF_FOUND_IN_KOTLIN) {
-                return null;
-            }
-            else if (searchRule == DescriptorSearchRule.INCLUDE_KOTLIN) {
-                // TODO: probably this is evil
-                return kotlinNamespaceDescriptor;
-            }
-            else {
-                throw new IllegalStateException("unknown searchRule: " + searchRule);
-            }
+            return searchRule.processFoundInKotlin(kotlinNamespaceDescriptor);
         }
 
         ResolverNamespaceData namespaceData = namespaceDescriptorCacheByFqn.get(qualifiedName);