private static HierarchicalMethodSignatureImpl copy(HierarchicalMethodSignature hi) {
   HierarchicalMethodSignatureImpl hierarchicalMethodSignature =
       new HierarchicalMethodSignatureImpl(hi);
   for (HierarchicalMethodSignature his : hi.getSuperSignatures()) {
     hierarchicalMethodSignature.addSuperSignature(copy(his));
   }
   return hierarchicalMethodSignature;
 }
 private static void mergeSupers(
     final HierarchicalMethodSignatureImpl existing,
     final HierarchicalMethodSignature superSignature) {
   for (HierarchicalMethodSignature existingSuper : existing.getSuperSignatures()) {
     if (existingSuper.getMethod() == superSignature.getMethod()) {
       for (HierarchicalMethodSignature signature : superSignature.getSuperSignatures()) {
         mergeSupers((HierarchicalMethodSignatureImpl) existingSuper, signature);
       }
       return;
     }
   }
   if (existing.getMethod() == superSignature.getMethod()) {
     List<HierarchicalMethodSignature> existingSupers = existing.getSuperSignatures();
     for (HierarchicalMethodSignature supers : superSignature.getSuperSignatures()) {
       if (!existingSupers.contains(supers)) existing.addSuperSignature(copy(supers));
     }
   } else {
     HierarchicalMethodSignatureImpl copy = copy(superSignature);
     existing.addSuperSignature(copy);
   }
 }
  // uses hierarchy signature tree if available, traverses class structure by itself otherwise
  public static boolean processDirectSuperMethodsSmart(
      @NotNull PsiMethod method, @NotNull Processor<PsiMethod> superMethodProcessor) {
    // boolean old = PsiSuperMethodUtil.isSuperMethod(method, superMethod);

    PsiClass aClass = method.getContainingClass();
    if (aClass == null) return false;

    if (!canHaveSuperMethod(method, true, false)) return false;

    Map<MethodSignature, HierarchicalMethodSignature> cachedMap =
        SIGNATURES_KEY.getCachedValueOrNull(aClass);
    if (cachedMap != null) {
      HierarchicalMethodSignature signature =
          cachedMap.get(method.getSignature(PsiSubstitutor.EMPTY));
      if (signature != null) {
        List<HierarchicalMethodSignature> superSignatures = signature.getSuperSignatures();
        for (HierarchicalMethodSignature superSignature : superSignatures) {
          if (!superMethodProcessor.process(superSignature.getMethod())) return false;
        }
        return true;
      }
    }

    PsiClassType[] directSupers = aClass.getSuperTypes();
    for (PsiClassType directSuper : directSupers) {
      PsiClassType.ClassResolveResult resolveResult = directSuper.resolveGenerics();
      if (resolveResult.getSubstitutor() != PsiSubstitutor.EMPTY) {
        // generics
        break;
      }
      PsiClass directSuperClass = resolveResult.getElement();
      if (directSuperClass == null) continue;
      PsiMethod[] candidates = directSuperClass.findMethodsBySignature(method, false);
      for (PsiMethod candidate : candidates) {
        if (PsiUtil.canBeOverriden(candidate)) {
          if (!superMethodProcessor.process(candidate)) return false;
        }
      }
      return true;
    }

    List<HierarchicalMethodSignature> superSignatures =
        method.getHierarchicalMethodSignature().getSuperSignatures();
    for (HierarchicalMethodSignature superSignature : superSignatures) {
      if (!superMethodProcessor.process(superSignature.getMethod())) return false;
    }
    return true;
  }
  // uses hierarchy signature tree if available, traverses class structure by itself otherwise
  public static boolean isSuperMethodSmart(
      @NotNull PsiMethod method, @NotNull PsiMethod superMethod) {
    // boolean old = PsiSuperMethodUtil.isSuperMethod(method, superMethod);

    if (method == superMethod) return false;
    PsiClass aClass = method.getContainingClass();
    PsiClass superClass = superMethod.getContainingClass();

    if (aClass == null || superClass == null || superClass == aClass) return false;

    if (!canHaveSuperMethod(method, true, false)) return false;

    PsiMethod[] superMethods = null;
    Map<MethodSignature, HierarchicalMethodSignature> cachedMap =
        SIGNATURES_KEY.getCachedValueOrNull(aClass);
    if (cachedMap != null) {
      HierarchicalMethodSignature signature =
          cachedMap.get(method.getSignature(PsiSubstitutor.EMPTY));
      if (signature != null) {
        superMethods =
            MethodSignatureUtil.convertMethodSignaturesToMethods(signature.getSuperSignatures());
      }
    }
    if (superMethods == null) {
      PsiClassType[] directSupers = aClass.getSuperTypes();
      List<PsiMethod> found = null;
      boolean canceled = false;
      for (PsiClassType directSuper : directSupers) {
        PsiClassType.ClassResolveResult resolveResult = directSuper.resolveGenerics();
        if (resolveResult.getSubstitutor() != PsiSubstitutor.EMPTY) {
          // generics
          canceled = true;
          break;
        }
        PsiClass directSuperClass = resolveResult.getElement();
        if (directSuperClass == null) continue;
        PsiMethod[] candidates = directSuperClass.findMethodsBySignature(method, false);
        if (candidates.length != 0) {
          if (found == null) found = new ArrayList<PsiMethod>();
          for (PsiMethod candidate : candidates) {
            if (PsiUtil.canBeOverriden(candidate)) found.add(candidate);
          }
        }
      }
      superMethods =
          canceled
              ? null
              : found == null ? PsiMethod.EMPTY_ARRAY : found.toArray(new PsiMethod[found.size()]);
    }
    if (superMethods == null) {
      superMethods =
          MethodSignatureUtil.convertMethodSignaturesToMethods(
              method.getHierarchicalMethodSignature().getSuperSignatures());
    }

    for (PsiMethod superCandidate : superMethods) {
      if (superMethod.equals(superCandidate) || isSuperMethodSmart(superCandidate, superMethod))
        return true;
    }
    return false;
  }
  private static Map<MethodSignature, HierarchicalMethodSignature> buildMethodHierarchy(
      PsiClass aClass,
      PsiSubstitutor substitutor,
      final boolean includePrivates,
      final Set<PsiClass> visited,
      boolean isInRawContext) {
    Map<MethodSignature, HierarchicalMethodSignature> result =
        new LinkedHashMap<MethodSignature, HierarchicalMethodSignature>();
    final Map<MethodSignature, List<PsiMethod>> sameParameterErasureMethods =
        new THashMap<MethodSignature, List<PsiMethod>>(
            MethodSignatureUtil.METHOD_PARAMETERS_ERASURE_EQUALITY);

    Map<MethodSignature, HierarchicalMethodSignatureImpl> map =
        new THashMap<MethodSignature, HierarchicalMethodSignatureImpl>(
            new TObjectHashingStrategy<MethodSignature>() {
              @Override
              public int computeHashCode(MethodSignature signature) {
                return MethodSignatureUtil.METHOD_PARAMETERS_ERASURE_EQUALITY.computeHashCode(
                    signature);
              }

              @Override
              public boolean equals(MethodSignature o1, MethodSignature o2) {
                if (!MethodSignatureUtil.METHOD_PARAMETERS_ERASURE_EQUALITY.equals(o1, o2))
                  return false;
                List<PsiMethod> list = sameParameterErasureMethods.get(o1);
                boolean toCheckReturnType = list != null && list.size() > 1;
                if (!toCheckReturnType) return true;
                PsiType returnType1 =
                    ((MethodSignatureBackedByPsiMethod) o1).getMethod().getReturnType();
                PsiType returnType2 =
                    ((MethodSignatureBackedByPsiMethod) o2).getMethod().getReturnType();
                if (returnType1 == null && returnType2 == null) return true;
                if (returnType1 == null || returnType2 == null) return false;

                PsiType erasure1 =
                    TypeConversionUtil.erasure(o1.getSubstitutor().substitute(returnType1));
                PsiType erasure2 =
                    TypeConversionUtil.erasure(o2.getSubstitutor().substitute(returnType2));
                return erasure1.equals(erasure2);
              }
            });

    for (PsiMethod method : aClass.getMethods()) {
      if (!method.isValid()) {
        throw new PsiInvalidElementAccessException(
            method, "class.valid=" + aClass.isValid() + "; name=" + method.getName());
      }
      if (!includePrivates && method.hasModifierProperty(PsiModifier.PRIVATE)) continue;
      final MethodSignatureBackedByPsiMethod signature =
          MethodSignatureBackedByPsiMethod.create(method, substitutor, isInRawContext);
      HierarchicalMethodSignatureImpl newH = new HierarchicalMethodSignatureImpl(signature);

      List<PsiMethod> list = sameParameterErasureMethods.get(signature);
      if (list == null) {
        list = new SmartList<PsiMethod>();
        sameParameterErasureMethods.put(signature, list);
      }
      list.add(method);

      LOG.assertTrue(newH.getMethod().isValid());
      result.put(signature, newH);
      map.put(signature, newH);
    }

    for (PsiClassType superType : aClass.getSuperTypes()) {
      PsiClassType.ClassResolveResult superTypeResolveResult = superType.resolveGenerics();
      PsiClass superClass = superTypeResolveResult.getElement();
      if (superClass == null) continue;
      if (!visited.add(superClass)) continue; // cyclic inheritance
      final PsiSubstitutor superSubstitutor = superTypeResolveResult.getSubstitutor();
      PsiSubstitutor finalSubstitutor =
          obtainFinalSubstitutor(superClass, superSubstitutor, substitutor, isInRawContext);

      final boolean isInRawContextSuper =
          (isInRawContext || PsiUtil.isRawSubstitutor(superClass, superSubstitutor))
              && superClass.getTypeParameters().length != 0;
      Map<MethodSignature, HierarchicalMethodSignature> superResult =
          buildMethodHierarchy(superClass, finalSubstitutor, false, visited, isInRawContextSuper);
      visited.remove(superClass);

      List<Pair<MethodSignature, HierarchicalMethodSignature>> flattened =
          new ArrayList<Pair<MethodSignature, HierarchicalMethodSignature>>();
      for (Map.Entry<MethodSignature, HierarchicalMethodSignature> entry : superResult.entrySet()) {
        HierarchicalMethodSignature hms = entry.getValue();
        MethodSignature signature = entry.getKey();
        PsiClass containingClass = hms.getMethod().getContainingClass();
        List<HierarchicalMethodSignature> supers =
            new ArrayList<HierarchicalMethodSignature>(hms.getSuperSignatures());
        for (HierarchicalMethodSignature aSuper : supers) {
          PsiClass superContainingClass = aSuper.getMethod().getContainingClass();
          if (containingClass != null
              && superContainingClass != null
              && !containingClass.isInheritor(superContainingClass, true)) {
            // methods must be inherited from unrelated classes, so flatten hierarchy here
            // class C implements SAM1, SAM2 { void methodimpl() {} }
            // hms.getSuperSignatures().remove(aSuper);
            flattened.add(
                new Pair<MethodSignature, HierarchicalMethodSignature>(signature, aSuper));
          }
        }
        putInMap(aClass, result, map, hms, signature);
      }
      for (Pair<MethodSignature, HierarchicalMethodSignature> pair : flattened) {
        putInMap(aClass, result, map, pair.second, pair.first);
      }
    }

    for (Map.Entry<MethodSignature, HierarchicalMethodSignatureImpl> entry : map.entrySet()) {
      HierarchicalMethodSignatureImpl hierarchicalMethodSignature = entry.getValue();
      MethodSignature methodSignature = entry.getKey();
      if (result.get(methodSignature) == null
          && PsiUtil.isAccessible(
              aClass.getProject(), hierarchicalMethodSignature.getMethod(), aClass, aClass)) {
        LOG.assertTrue(hierarchicalMethodSignature.getMethod().isValid());
        result.put(methodSignature, hierarchicalMethodSignature);
      }
    }

    return result;
  }