[Bug c++/126749] New: ICE in build_simple_base_path when initializing a static member of an incomplete derived class

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=126749

            Bug ID: 126749
           Summary: ICE in build_simple_base_path when initializing a
                    static member of an incomplete derived class
           Product: gcc
           Version: 17.0
            Status: UNCONFIRMED
          Severity: normal
          Priority: P3
         Component: c++
          Assignee: unassigned at gcc dot gnu.org
          Reporter: s.kimura.h41104 at gmail dot com
  Target Milestone: ---

Compiler Explorer: https://godbolt.org/z/jox7nhexd

Reproducer:
```
struct S {
  int foo;
  S operator|(S) const;
};

struct SS : S {
  static const SS ss;
  static const SS bar = SS{ss | ss};
}
```

Backtrace:
<source>:8:33: error: cannot convert from 'SS' to base class 'S' because 'SS'
is incomplete
    8 |   static const SS bar = SS{ss | ss};
      |                                 ^~
<source>:8:33: internal compiler error: in build_simple_base_path, at
cp/class.cc:613
0x2b97f28 diagnostics::context::diagnostic_impl(rich_location*,
diagnostics::metadata const*, diagnostics::option_id, char const*,
__va_list_tag (*) [1], diagnostics::kind)
        ???:0
0x2b8cb6b internal_error(char const*, ...)
        ???:0
0xb40b7e fancy_abort(char const*, int, char const*)
        ???:0
0xb99c28 build_base_path(tree_code, tree_node*, tree_node*, int, int)
        ???:0
0xb628f3 build_new_method_call(tree_node*, tree_node*, vec<tree_node*, va_gc,
vl_embed>**, tree_node*, int, tree_node**, int)
        ???:0
0xb63c4d build_special_member_call(tree_node*, tree_node*, vec<tree_node*,
va_gc, vl_embed>**, tree_node*, int, int)
        ???:0
0xb7d24a build_new_op(op_location_t const&, tree_code, int, tree_node*,
tree_node*, tree_node*, tree_node*, tree_node**, int)
        ???:0
0xe800c2 build_x_binary_op(op_location_t const&, tree_code, tree_node*,
tree_code, tree_node*, tree_code, tree_node*, tree_node**, int)
        ???:0
0xd96823 c_parse_file()
        ???:0
0xf29cf9 c_common_parse_file()
        ???:0