[Bug fortran/70330] New: ICE with -Wextra -Wno-unused-dummy-argument and unused optional dummy argument

[vladimir.fuka at gmail dot com]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=70330

            Bug ID: 70330
           Summary: ICE with -Wextra -Wno-unused-dummy-argument and unused
                    optional dummy argument
           Product: gcc
           Version: 5.3.0
            Status: UNCONFIRMED
          Severity: normal
          Priority: P3
         Component: fortran
          Assignee: unassigned at gcc dot gnu.org
          Reporter: vladimir.fuka at gmail dot com
  Target Milestone: ---

function f(o)
      optional o
    end function


causes

gfortran  -Wall -Wextra -Wno-unused-dummy-argument  ice.f90 
fft_full.f90:2:4:

     function f(o)
    1
Warning: Return value of function ‘f’ at (1) not set [-Wreturn-type]
‘
fft_full.f90:4:0:

     end function
 1
in pp_format, at pretty-print.c:614
0x102706d pp_format(pretty_printer*, text_info*)
        ../../gcc-5.3.0/gcc/pretty-print.c:614
0x1024432 diagnostic_report_diagnostic(diagnostic_context*, diagnostic_info*)
        ../../gcc-5.3.0/gcc/diagnostic.c:862
0x1024ad5 warning(int, char const*, ...)
        ../../gcc-5.3.0/gcc/diagnostic.c:1027
0x86fbeb do_warn_unused_parameter(tree_node*)
        ../../gcc-5.3.0/gcc/function.c:5247
0x79058a cgraph_node::finalize_function(tree_node*, bool)
        ../../gcc-5.3.0/gcc/cgraphunit.c:479
0x6e8f69 gfc_generate_function_code(gfc_namespace*)
        ../../gcc-5.3.0/gcc/fortran/trans-decl.c:5984
0x685e30 translate_all_program_units
        ../../gcc-5.3.0/gcc/fortran/parse.c:5343
0x685e30 gfc_parse_file()
        ../../gcc-5.3.0/gcc/fortran/parse.c:5540
0x6c52d5 gfc_be_parse_file
        ../../gcc-5.3.0/gcc/fortran/f95-lang.c:229
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