Description:
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When i try to rename a file, then to check if the source file exists, file_exists() returns me true. A conclusion is that a source file info is cached when using rename() function. 
My solution was to call clearcache() between rename() and file_exists(). I'm not sure if anyone else will consider it as a bug, but i suppose it's not a desired behavior.
In the Reproduce code i put casting into integer just for the sake of displaying 0 if the file doesn't exist instead of an empty string.

Reproduce code:
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rename('oldFile.txt', 'newFile.txt');
echo((int) file_exists('oldFile.txt');

Expected result:
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1

Actual result:
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0