http://gcc.gnu.org/bugzilla/show_bug.cgi?id=46196
--- Comment #11 from Mikael Morin <mikael at gcc dot gnu.org> 2010-10-30 12:51:54 UTC --- Another bug, we don't check that components are non-null before entering the loop. module type_a type a sequence end type a end module type_a module type_a_bis type a sequence end type a end module type_a_bis use type_a use type_a_bis, only: b => a type(b) :: y call bar(y) contains subroutine bar (x) type(a) :: x end subroutine bar end PS: Dominique, you can start hacking with this testcase. gfc_compare_derived_types is called with it (when comparing type of `y' vs type of `x'). PS2: we will need a new PR in the end.