Undefined index in Core/BAO/SchemaHandler.php

When CiviCRM is opened, at least under Joomla, you get a string of errors in the PHP log along the lines of:

Undefined index: civicrm_location_type in <joomla root>/administrator/components/com_civicrm/civicrm/CRM/Core\BAO/SchemaHandler.php on line 730.  The line in question reads as follows:

      foreach ($requiredIndices[$sigParts[0]] as $index) { 

and the error is because $sigParts[0] is not found in $requiredIndices.

In addition, there are a couple of examples of something like this:

    foreach ($existingIndices as $table => $indices) {
      CRM_Core_BAO_SchemaHandler::addIndexSignature($table, $indices);
      $extSigs[] = CRM_Utils_Array::collect('sig', $indices);
{{    }}}
    CRM_Utils_Array::flatten($extSigs, $existingSigs);

where the scope of $extSigs is within the foreach loop I believe, which means that the flatten function  doesn't have $extSigs to work on.

I thought I should flag this up before attempting to fix it.  There may be ramifications of which I am not aware.