Qt Creator missing autocomplete when using clang

[Marius_Linux]

Hi, I've recently switched from GCC to Clang, on Fedora 22.
But now I'm experiencing annoying problems with the autocomplete function of Qt Creator:
When including STL heades, e.g.
#include <algorithm>
Qt Creator will underline this yellow, with a file not found message, when using Clang, but not when using GCC.
So because of this, there is no autocompletion for members of the <algorithm> header, or any other STL header.
However, compilation of the code works without errors, and Clang seems to ahve the correct include paths.

Is there a way to fix this odd behaviour? I'd really prefer using Clang instead of GCC.
Thanks in advance,
Marius