Unhelpful "fatal error: error reading file data"

On replacing gcc by clang in my custom build system, puzzling failures occurred with an unhelpful message:
fatal error: error reading file data
This turned out to be clang's response to an especially 'bad' precompiled header left behind by my build system (gcc has a feature, not needed in clang, whereby pch files of different architectures can be placed in a directory *.h.gch).

$ ls -1
test.c
test.h
$ echo "" > test.h.gch
$ clang -include test.h test.c
fatal error: 'test.h.gch' does not appear to be a precompiled header file
1 diagnostic generated.
$ rm test.h.gch
$ mkdir test.h.gch
$ clang -include test.h test.c
fatal error: error reading file data
1 diagnostic generated.

Clang's message for a bad *.h.gch file is excellent. Could the same message be emitted if it's a directory?

Robert P.

Sure, please file a bugzilla to track this, thanks!

-Chris