http://gcc.gnu.org/bugzilla/show_bug.cgi?id=60474
--- Comment #5 from Richard Biener <rguenth at gcc dot gnu.org> --- type = signed_type_for (TREE_TYPE (e1)); tree_to_aff_combination (e1, type, &aff_e1); tree_to_aff_combination (e2, type, &aff_e2); signed_type_for (offset_type 0x7ffff6d9cc78) returns NULL_TREE. OFFSET_TYPE in the IL ... ugh. void fn1(A<int>&, int Layer::*, int) (struct A & p1, <<< Unknown tree: offset_type >>> p2, int p3) { I have a patch.