https://gcc.gnu.org/bugzilla/show_bug.cgi?id=100971
Bug ID: 100971 Summary: ICE: Bad IO basetype (7) Product: gcc Version: 12.0 Status: UNCONFIRMED Severity: normal Priority: P3 Component: fortran Assignee: unassigned at gcc dot gnu.org Reporter: gs...@t-online.de Target Milestone: --- This invalid code z1 affects versions down to at least r5. For reference, the case z0 is already rejected. $ cat z0.f90 program p type t end type class(t), allocatable :: a print *, a end $ cat z1.f90 program p type t end type class(t), allocatable :: a print *, [a] end $ gfortran-12-20210606 -c z0.f90 z0.f90:5:13: 5 | print *, a | 1 Error: Data transfer element at (1) cannot be polymorphic unless it is processed by a defined input/output procedure $ gfortran-12-20210606 -c z1.f90 f951: internal compiler error: Bad IO basetype (7) 0x6ea049 gfc_report_diagnostic ../../gcc/fortran/error.c:782 0x6eb76a gfc_internal_error(char const*, ...) ../../gcc/fortran/error.c:1402 0x7f9e09 transfer_expr ../../gcc/fortran/trans-io.c:2507 0x7fd430 gfc_trans_transfer(gfc_code*) ../../gcc/fortran/trans-io.c:2661 0x79e6c7 trans_code ../../gcc/fortran/trans.c:2138 0x7faefe build_dt ../../gcc/fortran/trans-io.c:2026 0x79e6a7 trans_code ../../gcc/fortran/trans.c:2110 0x7c4bc4 gfc_generate_function_code(gfc_namespace*) ../../gcc/fortran/trans-decl.c:6893 0x74b3f6 translate_all_program_units ../../gcc/fortran/parse.c:6461 0x74b3f6 gfc_parse_file() ../../gcc/fortran/parse.c:6730 0x79772f gfc_be_parse_file ../../gcc/fortran/f95-lang.c:212