Description:
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Error of mkdir doesn't show which parent directory does not exist. Instead it alway shows '/-' as directory.

Reproduce code:
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<?php
mkdir('/tmp/does/not/exist');
mkdir('/var/cache/does/not/exist');

Expected result:
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Warning: mkdir(): No such file or directory in /tmp on line 2
Warning: mkdir(): No such file or directory in /var/cache on line 3


Actual result:
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Warning: mkdir(): No such file or directory in /- on line 2
Warning: mkdir(): No such file or directory in /- on line 3