Ben, Omer I find that when running the testsuite, I get the garbage below, for ghci/should_run/T13456. Adding an empty file T13456.stderr seems to fix it in one of my trees, but not in another. Very strange. Any ideas? Simon Framework failures: T13456.run T13456 [Traceback (most recent call last): File "/home/simonpj/code/HEAD-1/testsuite/driver/testlib.py", line 996, in test_common_work do_test(name, way, func, args, files) File "/home/simonpj/code/HEAD-1/testsuite/driver/testlib.py", line 1094, in do_test result = func(*[name,way] + args) File "/home/simonpj/code/HEAD-1/testsuite/driver/testlib.py", line 1213, in ghci_script return simple_run( name, way, cmd, getTestOpts().extra_run_opts ) File "/home/simonpj/code/HEAD-1/testsuite/driver/testlib.py", line 1638, in simple_run stderr=read_stderr(name), File "/home/simonpj/code/HEAD-1/testsuite/driver/testlib.py", line 1808, in read_stderr return in_testdir(name, 'run.stderr').read_text(encoding='UTF-8') File "/usr/lib/python3.6/pathlib.py", line 1196, in read_text with self.open(mode='r', encoding=encoding, errors=errors) as f: File "/usr/lib/python3.6/pathlib.py", line 1183, in open opener=self._opener) File "/usr/lib/python3.6/pathlib.py", line 1037, in _opener return self._accessor.open(self, flags, mode) File "/usr/lib/python3.6/pathlib.py", line 387, in wrapped return strfunc(str(pathobj), *args) FileNotFoundError: [Errno 2] No such file or directory: 'T13456.run/T13456.run.stderr' ] (ghci)