protected @Nullable UnresolvableCollisionUsageInfo findCollision() {
    if (myInsertedName.equals(myOldName)) return null;
    PsiNamedElement variable = myElementInCopy;
    if (variable == null) return null;
    String newName = myInsertedName;
    List<UsageInfo> result = new ArrayList<>();
    RenamePsiElementProcessor.forElement(variable).findCollisions(variable, newName, Map.of(variable, newName), result);
    return ContainerUtil.findInstance(result, UnresolvableCollisionUsageInfo.class);
  }
protected @Nullable UnresolvableCollisionUsageInfo findCollision()