Changed before 20170618, gcc-7 compiles :


$ cat z1.cc
void foo (void)
{
  struct A;
  void A (int);
  void A (long);
}


$ gcc-7 -c z1.cc
$
$ gcc-8-20180311 -c z1.cc
z1.cc: In function 'void foo()':
z1.cc:5:16: internal compiler error: in pop_local_binding, at cp/name-lookup.c:2054
   void A (long);
                ^
0x714919 pop_local_binding(tree_node*, tree_node*)
        ../../gcc/cp/name-lookup.c:2054
0x6d7189 poplevel(int, int, int)
        ../../gcc/cp/decl.c:776
0x791d53 do_poplevel(tree_node*)
        ../../gcc/cp/semantics.c:451
0x792b2c finish_compound_stmt(tree_node*)
        ../../gcc/cp/semantics.c:1451
0x738887 cp_parser_compound_statement
        ../../gcc/cp/parser.c:11230
0x74a37e cp_parser_function_body
        ../../gcc/cp/parser.c:21778
0x74a37e cp_parser_ctor_initializer_opt_and_function_body
        ../../gcc/cp/parser.c:21813
0x74ab40 cp_parser_function_definition_after_declarator
        ../../gcc/cp/parser.c:26828
0x74dce6 cp_parser_function_definition_from_specifiers_and_declarator
        ../../gcc/cp/parser.c:26745
0x74dce6 cp_parser_init_declarator
        ../../gcc/cp/parser.c:19502
0x74ee0f cp_parser_simple_declaration
        ../../gcc/cp/parser.c:13057
0x74fba8 cp_parser_block_declaration
        ../../gcc/cp/parser.c:12883
0x7577ee cp_parser_declaration
        ../../gcc/cp/parser.c:12780
0x756356 cp_parser_declaration_seq_opt
        ../../gcc/cp/parser.c:12656
0x75665f cp_parser_translation_unit
        ../../gcc/cp/parser.c:4561
0x75665f c_parse_file()
        ../../gcc/cp/parser.c:39005
0x80ce65 c_common_parse_file()
        ../../gcc/c-family/c-opts.c:1132