To reproduce:

TEXT TO cRes
test()
DEFINE CLASS test as Custom
HIDDEN PROCEDURE test
ENDPROC
ENDDEFINE
ENDTEXT
STRTOFILE( cRes, 'test1.prg' )
BUILD PROJECT test1 FROM test1

Observed result: no error

Expected result:

Error

Unable to find function 'TEST' referenced in test1.prg at line 1

Platform: Visual FoxPro 08.00.0000.2521 for Windows

Remarks

Dangerous. If I include somebodys class in my code,
I must MANUALLY check that all this class method (even hidden!) names
are not the same as my external prg files!
EXTERNAL PROCEDURE test.prg
fixes this, but I'm expecting that this must be done by vfp itself.

Any idea how to fix this?