Description:
------------
I realise this might be impossible to debug, but I've been seeing a 'random' crash in PHP 5.6.2 when there is a fatal error in a script.

I haven't been able to reproduce it in a simple script however it was captured in a valgrind run.

Possibly related to any of 63481, 64827, 64896, 68121.

Expected result:
----------------
No crash.

Actual result:
--------------
The output from the script when run through valgrind is:

PHP Catchable fatal error:  Argument 1 passed to BaseReality\ViewModel\SiteViewModel::getDisplayableNote() must be an instance of BaseReality\Content\Note, instance of BaseReality\DisplayableContent\DisplayableNote given in /home/intahwebz/intahwebz/src/BaseReality/ViewModel/SiteViewModel.php on line 120


==7433== Invalid read of size 1
==7433==    at 0x68F449: _free_function (php_reflection.c:274)
==7433==    by 0x68F509: reflection_free_objects_storage (php_reflection.c:298)
==7433==    by 0x839D26: zend_objects_store_del_ref_by_handle_ex (zend_objects_API.c:226)
==7433==    by 0x839D5D: zend_objects_store_del_ref (zend_objects_API.c:178)
==7433==    by 0x7F8CAF: _zval_ptr_dtor (zend_variables.h:35)
==7433==    by 0x817E9A: zend_hash_destroy (zend_hash.c:548)
==7433==    by 0x808056: _zval_dtor_func (zend_variables.c:45)
==7433==    by 0x7F8CAF: _zval_ptr_dtor (zend_variables.h:35)
==7433==    by 0x8334C6: zend_object_std_dtor (zend_objects.c:54)
==7433==    by 0x8334F8: zend_objects_free_object_storage (zend_objects.c:137)
==7433==    by 0x839D26: zend_objects_store_del_ref_by_handle_ex (zend_objects_API.c:226)
==7433==    by 0x839D5D: zend_objects_store_del_ref (zend_objects_API.c:178)
==7433==  Address 0x16f060c0 is 0 bytes inside a block of size 248 free'd
==7433==    at 0x4C273F0: free (vg_replace_malloc.c:446)
==7433==    by 0x817ACD: zend_hash_bucket_delete (zend_hash.c:185)
==7433==    by 0x817BF5: zend_hash_reverse_apply (zend_hash.c:733)
==7433==    by 0x128D7E10: zend_accel_fast_shutdown (ZendAccelerator.c:2352)
==7433==    by 0x128DC0FF: accel_deactivate (ZendAccelerator.c:2385)
==7433==    by 0x7FC610: zend_llist_apply (zend_llist.c:191)
==7433==    by 0x7FB8E7: shutdown_executor (zend_execute_API.c:246)
==7433==    by 0x809732: zend_deactivate (zend.c:963)
==7433==    by 0x79C130: php_request_shutdown (main.c:1884)
==7433==    by 0x8B9DBE: do_cli (php_cli.c:1177)
==7433==    by 0x8BB6CC: main (php_cli.c:1378)
==7433== 
zend_mm_heap corrupted