The entire error message (sorry for not including it earlier):
Error while trying to load definition for system pcl-test from pathname /Volumes/share2/src/clnet/cmucl/snapshot-2017-10/tests/pcl.lisp: Circular dependency: ((#<ASDF/FIND-SYSTEM:DEFINE-OP> . #<ASDF/SYSTEM:SYSTEM "pcl-test">) (#<ASDF/LISP-ACTION:LOAD-OP> . #<ASDF/SYSTEM:SYSTEM "pcl-test">) (#<ASDF/LISP-ACTION:LOAD-OP> . #<ASDF/LISP-ACTION:CL-SOURCE-FILE "pcl-test" "pkg">) (#<ASDF/LISP-ACTION:PREPARE-OP> . #<ASDF/LISP-ACTION:CL-SOURCE-FILE "pcl-test" "pkg">) (#<ASDF/LISP-ACTION:PREPARE-OP> . #<ASDF/SYSTEM:SYSTEM "pcl-test">))
Restarts:
0: [CONTINUE ] Return NIL from load of #P"/Volumes/share2/src/clnet/cmucl/snapshot-2017-10/tests/pcl.lisp".
1: [RETRY ] Retry #<DEFINE-OP> on #<SYSTEM "pcl-test">.
2: [ACCEPT ] Continue, treating #<DEFINE-OP> on #<SYSTEM "pcl-test"> as having been successful.
3: Retry ASDF operation.
4: [CLEAR-CONFIGURATION-AND-RETRY] Retry ASDF operation after resetting the configuration.
5: Retry ASDF operation.
6: Retry ASDF operation after resetting the configuration.
7: Return NIL from load of #P"/Volumes/share2/src/clnet/cmucl/snapshot-2017-10/tests/pcl.lisp".
8: [ABORT ] Skip remaining initializations.
The file gets loaded from tests/run-tests.lisp
I guess maybe that defsystem should be in its own file that pcl.lisp loads? I have a vague memory that you helped fix some similar issues with some asdf defsystems that I had, that were working fine but stopped working after some upgrade, maybe to 3.2.x.