https://gcc.gnu.org/bugzilla/show_bug.cgi?id=84543
Bug ID: 84543 Summary: undefined reference to __copy_INTEGER_4_.3788 Product: gcc Version: 8.0.1 Status: UNCONFIRMED Severity: normal Priority: P3 Component: fortran Assignee: unassigned at gcc dot gnu.org Reporter: neil.n.carlson at gmail dot com Target Milestone: --- I stumbled across this problem while reducing an actual error to a minimal test case (PR84539). I wasn't going to bother reporting it (it seems a bit too silly) but reconsidered. Maybe this means something significant to a developer; I'll let you decide. $ cat bug.f90 class(*), allocatable :: x x = 42 end $ gfortran bug.f90 /tmp/cclHGRhz.o:(.rodata+0x60): undefined reference to `__copy_INTEGER_4_.3788' collect2: error: ld returned 1 exit status And similar with a real or character value, and presumably with any of the kinds that gfortran supports. The link error goes away if you add a TYPE IS clause for the type of the value; e.g. class(*), allocatable :: x x = 42 select type (x) type is (integer) end select end