drupal Internal Zend error - Missing class information for condition has been previously compiled. ConditionInterface.php

I hadn't seen this error before so had to report it.

PHP Fatal error:  Internal Zend error - Missing class information for /**\n   * Check whether a condition has been previously compiled.\n   *\n   * @return\n   *   TRUE if the condition has been previously compiled.\n   */ in /DRUPAL8/core/lib/Drupal/Core/Database/Query/ConditionInterface.php on line 159

I'll try blowing away the database to see if it comes back or not.

This is with the latest git code from this morning & I also deleted the core files & then did a git reset --hard to set things down to how they should be.