public static boolean isClassEquivalentTo(@NotNull PsiClass aClass, PsiElement another) {
    if (aClass == another) return true;
    if (!(another instanceof PsiClass)) return false;
    String name1 = aClass.getName();
    if (name1 == null) return false;
    if (!another.isValid()) return false;
    String name2 = ((PsiClass) another).getName();
    if (name2 == null) return false;
    if (name1.hashCode() != name2.hashCode()) return false;
    if (!name1.equals(name2)) return false;
    String qName1 = aClass.getQualifiedName();
    String qName2 = ((PsiClass) another).getQualifiedName();
    if (qName1 == null || qName2 == null) {
      //noinspection StringEquality
      if (qName1 != qName2) return false;

      if (aClass instanceof PsiTypeParameter && another instanceof PsiTypeParameter) {
        PsiTypeParameter p1 = (PsiTypeParameter) aClass;
        PsiTypeParameter p2 = (PsiTypeParameter) another;

        return p1.getIndex() == p2.getIndex()
            && aClass.getManager().areElementsEquivalent(p1.getOwner(), p2.getOwner());
      } else {
        return false;
      }
    }
    if (qName1.hashCode() != qName2.hashCode() || !qName1.equals(qName2)) {
      return false;
    }

    if (originalElement(aClass).equals(originalElement((PsiClass) another))) {
      return true;
    }

    final PsiFile file1 = aClass.getContainingFile().getOriginalFile();
    final PsiFile file2 = another.getContainingFile().getOriginalFile();

    // see com.intellij.openapi.vcs.changes.PsiChangeTracker
    // see com.intellij.psi.impl.PsiFileFactoryImpl#createFileFromText(CharSequence,PsiFile)
    final PsiFile original1 = file1.getUserData(PsiFileFactory.ORIGINAL_FILE);
    final PsiFile original2 = file2.getUserData(PsiFileFactory.ORIGINAL_FILE);
    if (original1 == original2 && original1 != null
        || original1 == file2
        || original2 == file1
        || file1 == file2) {
      return compareClassSeqNumber(aClass, (PsiClass) another);
    }

    final FileIndexFacade fileIndex =
        ServiceManager.getService(file1.getProject(), FileIndexFacade.class);
    final VirtualFile vfile1 = file1.getViewProvider().getVirtualFile();
    final VirtualFile vfile2 = file2.getViewProvider().getVirtualFile();
    boolean lib1 = fileIndex.isInLibraryClasses(vfile1);
    boolean lib2 = fileIndex.isInLibraryClasses(vfile2);

    return (fileIndex.isInSource(vfile1) || lib1) && (fileIndex.isInSource(vfile2) || lib2);
  }
  private static void findTypeParameterExternalUsages(
      final PsiTypeParameter typeParameter, final Collection<UsageInfo> usages) {
    PsiTypeParameterListOwner owner = typeParameter.getOwner();
    if (owner != null) {
      final PsiTypeParameterList parameterList = owner.getTypeParameterList();
      if (parameterList != null) {
        final int paramsCount = parameterList.getTypeParameters().length;
        final int index = parameterList.getTypeParameterIndex(typeParameter);

        ReferencesSearch.search(owner)
            .forEach(
                reference -> {
                  if (reference instanceof PsiJavaCodeReferenceElement) {
                    final PsiReferenceParameterList parameterList1 =
                        ((PsiJavaCodeReferenceElement) reference).getParameterList();
                    if (parameterList1 != null) {
                      PsiTypeElement[] typeArgs = parameterList1.getTypeParameterElements();
                      if (typeArgs.length > index) {
                        if (typeArgs.length == 1
                            && paramsCount > 1
                            && typeArgs[0].getType() instanceof PsiDiamondType) return true;
                        usages.add(
                            new SafeDeleteReferenceJavaDeleteUsageInfo(
                                typeArgs[index], typeParameter, true));
                      }
                    }
                  }
                  return true;
                });
      }
    }
  }
 public String toString() {
   @NonNls StringBuilder buffer = new StringBuilder();
   final Set<Map.Entry<PsiTypeParameter, PsiType>> set = mySubstitutionMap.entrySet();
   for (Map.Entry<PsiTypeParameter, PsiType> entry : set) {
     final PsiTypeParameter typeParameter = entry.getKey();
     buffer.append(typeParameter.getName());
     final PsiElement owner = typeParameter.getOwner();
     if (owner instanceof PsiClass) {
       buffer.append(" of ");
       buffer.append(((PsiClass) owner).getQualifiedName());
     } else if (owner instanceof PsiMethod) {
       buffer.append(" of ");
       buffer.append(((PsiMethod) owner).getName());
       buffer.append(" in ");
       buffer.append(((PsiMethod) owner).getContainingClass().getQualifiedName());
     }
     buffer.append(" -> ");
     if (entry.getValue() != null) {
       buffer.append(entry.getValue().getCanonicalText());
     } else {
       buffer.append("null");
     }
     buffer.append('\n');
   }
   return buffer.toString();
 }
 private boolean check(PsiTypeParameter check) {
   final PsiTypeParameterListOwner owner = check.getOwner();
   if (owner == myMethod) {
     return true;
   } else if (owner == myClass) {
     return true;
   }
   return false;
 }