https://gcc.gnu.org/bugzilla/show_bug.cgi?id=56496
--- Comment #3 from G. Steinmetz <gs...@t-online.de> --- Further reduced : $ cat z1.f90 program p class(*), allocatable :: a[:] allocate (integer :: a[*]) select type (a) type is (integer) end select end $ gfortran-8-20171105 -c z1.f90 -fcoarray=single z1.f90:1:0: program p internal compiler error: in gfc_conv_array_ref, at fortran/trans-array.c:3512 0x739662 gfc_conv_array_ref(gfc_se*, gfc_array_ref*, gfc_expr*, locus*) ../../gcc/fortran/trans-array.c:3512 0x7667cd gfc_conv_variable ../../gcc/fortran/trans-expr.c:2680 0x79b575 trans_associate_var ../../gcc/fortran/trans-stmt.c:1769 0x79b575 gfc_trans_block_construct(gfc_code*) ../../gcc/fortran/trans-stmt.c:1884 0x72ffd7 trans_code ../../gcc/fortran/trans.c:1924 0x79d4a7 gfc_trans_select_type_cases ../../gcc/fortran/trans-stmt.c:2475 0x79d4a7 gfc_trans_select_type(gfc_code*) ../../gcc/fortran/trans-stmt.c:3185 0x72ff47 trans_code ../../gcc/fortran/trans.c:1944 0x79b208 gfc_trans_block_construct(gfc_code*) ../../gcc/fortran/trans-stmt.c:1877 0x72ffd7 trans_code ../../gcc/fortran/trans.c:1924 0x756bfc gfc_generate_function_code(gfc_namespace*) ../../gcc/fortran/trans-decl.c:6421 0x6e8b90 translate_all_program_units ../../gcc/fortran/parse.c:6091 0x6e8b90 gfc_parse_file() ../../gcc/fortran/parse.c:6294 0x72d3bf gfc_be_parse_file ../../gcc/fortran/f95-lang.c:204