private function _checkCurrentLocks()
    {
        foreach ($this->_classHierarchy as $classInfo) {
            // FATAL: If any part of our class hierarchy is already locked ("is
            // being compiled right now", higher up the call stack), then it's a
            // bad map with circular "import"-statements.
            // NOTE: This specifically protects against the dangerous scenario
            // of importing classes derived from our hierarchy but whose
            // classname isn't in the current class hierarchy, so they weren't
            // blocked by the "import-target sanity checks". So when they get
            // to their own sub-compilation, their class hierarchy is checked
            // here and we'll discover their circular inheritance.
            if (isset($this->_propertyMapCache->compilerLocks[$classInfo['className']])) {
                // NOTE: strictClassName goes in "arg1" because it's being
                // compiled earlier than us, so we're definitely the "arg2".
                throw new CircularPropertyMapException(
                    $classInfo['strictClassName'],
                    $this->_strictSolveClassName
                );
            }
        }
    }