Description:
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Even with a __get() that returns by reference, attempting to return an overloaded property by reference directly will return by value with a notice.

A work-around is to assign the overloaded property by reference to another variable, and return that variable. However, I think it should be possible to return the property by reference directly.

This affects 5.2.5 and the latest 5.3 and 6.0 snaps.

Reproduce code:
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Testcase over 20 lines - see: http://pastebin.com/f35a74bdb

Expected result:
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Get reference to global via return-by-ref __get() called implicitly - OK:
string(13) "First change!"

Get reference to global via return-by-ref __get() called explicitly from return-by-ref function - OK:
string(14) "Second change!"

Get reference to global via return-by-ref __get() called implicitly from return-by-ref function:
string(13) "Third change!"


Actual result:
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Get reference to global via return-by-ref __get() called implicitly - OK:
string(13) "First change!"

Get reference to global via return-by-ref __get() called explicitly from return-by-ref function - OK:
string(14) "Second change!"

Get reference to global via return-by-ref __get() called implicitly from return-by-ref function:

Notice: Only variable references should be returned by reference in %s on line 20
string(8) "original"