Description:
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PHP doesn't unset an object if it contains variables that include references to itself. Despite being unset, the objects remain in memory until the end of the request. This can lead to scripts consuming large amounts of memory when larger and more complex objects are being employed.

Reproduce code:
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http://www.indelible.org.uk/reproduce.php

Expected result:
----------------
0
Create A
Create B
Destroying B
Destroying A
1
Create A
Create B
Destroying B
Destroying A
2
Create A
Create B
Destroying B
Destroying A
End of Loop

Actual result:
--------------
0
Create A
Create B
1
Create A
Create B
2
Create A
Create B
End of Loop
Destroying A
Destroying B
Destroying A
Destroying B
Destroying A
Destroying B