[Bug fortran/80260] New: [7 Regression] ICE with polymorphic array section actual argument

["damian at sourceryinstitute dot org" <gcc-bugzilla at gcc dot gnu dot org>]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=80260

            Bug ID: 80260
           Summary: [7 Regression] ICE with polymorphic array section
                    actual argument
           Product: gcc
           Version: 7.0.1
            Status: UNCONFIRMED
          Severity: normal
          Priority: P3
         Component: fortran
          Assignee: unassigned at gcc dot gnu.org
          Reporter: damian at sourceryinstitute dot org
  Target Milestone: ---

The code below causes an internal compiler error with gfortran 7.0.1, but
compiles and executes cleanly with gfortran 6.3.0

$ cat foobar.f90 
    type foo
    end type foo
    type, extends(foo) :: bar
    end type
contains
    subroutine f(x)
      class(foo) x(:,:)
      select type(x)
        class is (bar)
          call g(x(1,:))
      end select
    end subroutine
    subroutine g(y)
      class(bar) y(:)
    end subroutine
end

$ gfortran --version
GNU Fortran (GCC) 7.0.1 20170326 (experimental)
-- snip --

$ gfortran foobar.f90 
foobar.f90:10:0:

           call g(x(1,:))

internal compiler error: Segmentation fault
0xbe60ff crash_signal
       
/home/rouson/Desktop/Builds/opencoarrays/prerequisites/downloads/trunk/gcc/toplev.c:337
0x6c70d9 gfc_conv_scalarized_array_ref
       
/home/rouson/Desktop/Builds/opencoarrays/prerequisites/downloads/trunk/gcc/fortran/trans-array.c:3229
0x6c8344 gfc_conv_array_ref(gfc_se*, gfc_array_ref*, gfc_expr*, locus*)
       
/home/rouson/Desktop/Builds/opencoarrays/prerequisites/downloads/trunk/gcc/fortran/trans-array.c:3397
0x701ffd gfc_conv_variable
       
/home/rouson/Desktop/Builds/opencoarrays/prerequisites/downloads/trunk/gcc/fortran/trans-expr.c:2680
0x6fdcda gfc_conv_expr(gfc_se*, gfc_expr*)
       
/home/rouson/Desktop/Builds/opencoarrays/prerequisites/downloads/trunk/gcc/fortran/trans-expr.c:7805
0x6d7796 gfc_conv_expr_descriptor(gfc_se*, gfc_expr*)
       
/home/rouson/Desktop/Builds/opencoarrays/prerequisites/downloads/trunk/gcc/fortran/trans-array.c:7184
0x6fa627 gfc_conv_procedure_call(gfc_se*, gfc_symbol*, gfc_actual_arglist*,
gfc_expr*, vec<tree_node*, va_gc, vl_embed>*)
       
/home/rouson/Desktop/Builds/opencoarrays/prerequisites/downloads/trunk/gcc/fortran/trans-expr.c:5319
0x7443ba gfc_trans_call(gfc_code*, bool, tree_node*, tree_node*, bool)
       
/home/rouson/Desktop/Builds/opencoarrays/prerequisites/downloads/trunk/gcc/fortran/trans-stmt.c:406
0x6bc658 trans_code
       
/home/rouson/Desktop/Builds/opencoarrays/prerequisites/downloads/trunk/gcc/fortran/trans.c:1891
0x748b88 gfc_trans_block_construct(gfc_code*)
       
/home/rouson/Desktop/Builds/opencoarrays/prerequisites/downloads/trunk/gcc/fortran/trans-stmt.c:1821
0x6bc407 trans_code
       
/home/rouson/Desktop/Builds/opencoarrays/prerequisites/downloads/trunk/gcc/fortran/trans.c:1919
0x7403f3 gfc_trans_if_1
       
/home/rouson/Desktop/Builds/opencoarrays/prerequisites/downloads/trunk/gcc/fortran/trans-stmt.c:1321
0x74859a gfc_trans_if(gfc_code*)
       
/home/rouson/Desktop/Builds/opencoarrays/prerequisites/downloads/trunk/gcc/fortran/trans-stmt.c:1352
0x6bc477 trans_code
       
/home/rouson/Desktop/Builds/opencoarrays/prerequisites/downloads/trunk/gcc/fortran/trans.c:1911
0x74b282 gfc_trans_select_type_cases
       
/home/rouson/Desktop/Builds/opencoarrays/prerequisites/downloads/trunk/gcc/fortran/trans-stmt.c:2419
0x74b282 gfc_trans_select_type(gfc_code*)
       
/home/rouson/Desktop/Builds/opencoarrays/prerequisites/downloads/trunk/gcc/fortran/trans-stmt.c:3130
0x6bc377 trans_code
       
/home/rouson/Desktop/Builds/opencoarrays/prerequisites/downloads/trunk/gcc/fortran/trans.c:1939
0x748b88 gfc_trans_block_construct(gfc_code*)
       
/home/rouson/Desktop/Builds/opencoarrays/prerequisites/downloads/trunk/gcc/fortran/trans-stmt.c:1821
0x6bc407 trans_code
       
/home/rouson/Desktop/Builds/opencoarrays/prerequisites/downloads/trunk/gcc/fortran/trans.c:1919
0x6ee028 gfc_generate_function_code(gfc_namespace*)
       
/home/rouson/Desktop/Builds/opencoarrays/prerequisites/downloads/trunk/gcc/fortran/trans-decl.c:6332
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