diff --git a/plugins/groovy/src/org/jetbrains/plugins/groovy/dsl/toplevel/ClassContextFilter.java b/plugins/groovy/src/org/jetbrains/plugins/groovy/dsl/toplevel/ClassContextFilter.java
index 4fbb04adaaa5..0cdcd2890473 100644
--- a/plugins/groovy/src/org/jetbrains/plugins/groovy/dsl/toplevel/ClassContextFilter.java
+++ b/plugins/groovy/src/org/jetbrains/plugins/groovy/dsl/toplevel/ClassContextFilter.java
@@ -4,15 +4,13 @@ import com.intellij.openapi.util.Condition;
 import com.intellij.openapi.util.Key;
 import com.intellij.openapi.util.Pair;
 import com.intellij.patterns.ElementPattern;
-import com.intellij.psi.JavaPsiFacade;
-import com.intellij.psi.PsiClassType;
-import com.intellij.psi.PsiFile;
-import com.intellij.psi.PsiType;
+import com.intellij.psi.*;
 import com.intellij.util.ProcessingContext;
 import com.intellij.util.containers.ConcurrentHashMap;
 import org.jetbrains.annotations.NotNull;
 import org.jetbrains.plugins.groovy.dsl.GroovyClassDescriptor;
 import org.jetbrains.plugins.groovy.lang.psi.impl.statements.expressions.TypesUtil;
+import org.jetbrains.plugins.groovy.lang.resolve.NonCodeMembersContributor;
 
 import java.util.Map;
 
@@ -69,6 +67,18 @@ public class ClassContextFilter implements ContextFilter {
   }
 
   public static boolean isSubtype(PsiType checked, PsiFile placeFile, String typeText) {
+    final boolean isClassType = checked instanceof PsiClassType;
+    if (isClassType) {
+      final PsiClass psiClass = ((PsiClassType)checked).resolve();
+      if (psiClass != null) {
+        final int i = typeText.indexOf("<");
+        String rawName = i > 0 ? typeText.substring(0, i) : typeText;
+        if (!NonCodeMembersContributor.getParentClassNames(psiClass).contains(rawName)) {
+          return false;
+        }
+      }
+    }
+
     PsiType myType = getCachedType(typeText, placeFile);
     if (checked == PsiType.NULL) return myType == PsiType.NULL;
     return TypesUtil.isAssignable(myType, checked, placeFile.getManager(), placeFile.getResolveScope(), false);
diff --git a/plugins/groovy/src/org/jetbrains/plugins/groovy/gant/GantMemberContributor.java b/plugins/groovy/src/org/jetbrains/plugins/groovy/gant/GantMemberContributor.java
index 486317ff2129..cf6e11289060 100644
--- a/plugins/groovy/src/org/jetbrains/plugins/groovy/gant/GantMemberContributor.java
+++ b/plugins/groovy/src/org/jetbrains/plugins/groovy/gant/GantMemberContributor.java
@@ -44,7 +44,7 @@ public class GantMemberContributor extends NonCodeMembersContributor {
                                      PsiScopeProcessor processor,
                                      GroovyPsiElement place,
                                      ResolveState state) {
-    if (aClass != null && Arrays.asList(getParentClassNames(aClass)).contains("groovy.util.AntBuilder")) {
+    if (aClass != null && getParentClassNames(aClass).contains("groovy.util.AntBuilder")) {
       processAntTasks(processor, place, state);
       return;
     }
diff --git a/plugins/groovy/src/org/jetbrains/plugins/groovy/lang/resolve/NonCodeMembersContributor.java b/plugins/groovy/src/org/jetbrains/plugins/groovy/lang/resolve/NonCodeMembersContributor.java
index ffe38b4b2ab1..749900275613 100644
--- a/plugins/groovy/src/org/jetbrains/plugins/groovy/lang/resolve/NonCodeMembersContributor.java
+++ b/plugins/groovy/src/org/jetbrains/plugins/groovy/lang/resolve/NonCodeMembersContributor.java
@@ -40,7 +40,7 @@ import java.util.*;
 public abstract class NonCodeMembersContributor {
   private static final ExtensionPointName<NonCodeMembersContributor> EP_NAME = ExtensionPointName.create("org.intellij.groovy.membersContributor");
 
-  private static final LightCacheKey<String[]> KEY = LightCacheKey.create();
+  private static final LightCacheKey<Set<String>> KEY = LightCacheKey.create();
   
   private static volatile MultiMap<String, NonCodeMembersContributor> ourClassSpecifiedContributors;
   private static NonCodeMembersContributor[] ourAllTypeContributors;
@@ -111,17 +111,16 @@ public abstract class NonCodeMembersContributor {
     return GroovyDslFileIndex.processExecutors(qualifierType, place, processor, state);
   }
 
-  protected static String[] getParentClassNames(@NotNull PsiClass aClass) {
-    String[] superClassNames = KEY.getCachedValue(aClass);
+  public static Set<String> getParentClassNames(@NotNull PsiClass aClass) {
+    Set<String> superClassNames = KEY.getCachedValue(aClass);
     if (superClassNames == null) {
       Set<PsiClass> superClasses = new HashSet<PsiClass>();
       superClasses.add(aClass);
       InheritanceUtil.getSuperClasses(aClass, superClasses, true);
 
-      superClassNames = new String[superClasses.size()];
-      int i = 0;
+      superClassNames = new HashSet<String>();
       for (PsiClass superClass : superClasses) {
-        superClassNames[i++] = superClass.getQualifiedName();
+        superClassNames.add(superClass.getQualifiedName());
       }
 
       superClassNames = KEY.putCachedValue(aClass, superClassNames);