Compiled ... "-2 clauses"

I loaded and ran some test code. Then I added one test and typed make. The output from the compilation seems wrong:

?- make.
% /home/peter/src/nerdle/test_nerdle compiled into test_nerdle 0.09 sec, -2 clauses
...
% All 486 tests passed in 12.059 seconds (64.550 cpu)
true.

Why did it show “-2 clauses” when I added a clause? (Actually a test, but I presume it’s the same thing)

Yes, it looks like the clause count admin per file is not completely ok. Doesn’t seem important enough to start digging … But of course, if anyone wants, please do. The stuff is in pl-srcfile.c. The reported stat is the difference in the numer_of_clauses property of a source file.