https://gcc.gnu.org/bugzilla/show_bug.cgi?id=94623
--- Comment #15 from Iain Buclaw <ibuclaw at gdcproject dot org> --- Created attachment 48316 --> https://gcc.gnu.org/bugzilla/attachment.cgi?id=48316&action=edit adjust hardcoded index of Error.bypassException Can you apply this and see if it goes away? If this fixes it, then that answer is almost certainly is yes, you do have another (newer) D compiler installed. You can also confirm by compiling the test with: gdc -v That will dump all front-end related information about the imports/semantic passes (including where a module was found).
