Clang code model failure

Getting the following error, on an empty file with just

#include <QObject>
QObject obj;

Parsing /home/alevy/dev/score/src/lib/score/graphics/RectItem.cpp: 0.0006 (100.0%) 0.0001 (100.0%) 0.0008 (100.0%) 0.0008 (100.0%)
error: retain documentation comments from system headers in the AST was disabled in PCH file but is currently enabled
Parsing /home/alevy/dev/score/src/lib/score/graphics/RectItem.cpp failed: CXError_ASTReadError
Reparsing /home/alevy/dev/score/src/lib/score/graphics/RectItem.cpp failed: 3

Tried to enable / disable the "Disable PCHs" toggle in the QTC code model settings, and to change the clang model warnings configuration. Other (real, complex) files in the same project work fine.