http://gcc.gnu.org/bugzilla/show_bug.cgi?id=47546
--- Comment #8 from janus at gcc dot gnu.org 2011-02-02 19:31:39 UTC --- This is a *very* strange bug, to say the least. Here is a reduced test case: module hydro_types implicit none end module hydro_types module hydro_state implicit none type :: state_t real :: U integer :: n end type private public :: state_t contains subroutine init type(state_t) :: this end subroutine init end module hydro_state module hydro_speeds use hydro_state implicit none contains subroutine speeds_cell (st, c_l, c_r) class(state_t) :: st real :: c_l(st%n) real :: c_r(st%n) end subroutine speeds_cell end module hydro_speeds module hydro_fluxes use hydro_state use hydro_speeds end module Putting this in a single file and compiling still gives me the error: use hydro_speeds 1 Interner Fehler bei (1): free_pi_tree(): Unresolved fixup I'm not quite sure it is related to OOP. There is still one CLASS variable in there which I could not remove. On the other hand, the failure is very elusive: Even removing the 'implicit none' line in the module 'hydro_types' (which btw is never used) will make it go away for me.