[Bug c++/92536] New: [10 Regression] ICE when trying to using deduction guide following unknown type error

[redi at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=92536

            Bug ID: 92536
           Summary: [10 Regression] ICE when trying to using deduction
                    guide following unknown type error
           Product: gcc
           Version: 10.0
            Status: UNCONFIRMED
          Keywords: error-recovery, ice-on-invalid-code
          Severity: normal
          Priority: P3
         Component: c++
          Assignee: unassigned at gcc dot gnu.org
          Reporter: redi at gcc dot gnu.org
  Target Milestone: ---

namespace std
{
  struct stop_token { };

  template<typename Callback>
    struct stop_callback
    {
      template<typename C>
      stop_callback(stop_token, C&&) { }
    };

template<typename _Callback>
    stop_callback(stop_token, _Callback) -> stop_callback<_Callback>;
}

int main()
{
  std::stop_token tok;
  std::function<void()> f([](){});
  std::stop_callback cb(tok, f);
}

This crashes when compiled with -std=gnu++17

stop.cc: In function 'int main()':
stop.cc:19:8: error: 'function' is not a member of 'std'
   19 |   std::function<void()> f([](){});
      |        ^~~~~~~~
stop.cc:1:1: note: 'std::function' is defined in header '<functional>'; did you
forget to '#include <functional>'?
  +++ |+#include <functional>
    1 | namespace std
stop.cc:19:25: error: 'f' was not declared in this scope
   19 |   std::function<void()> f([](){});
      |                         ^
stop.cc:20:31: error: class template argument deduction failed:
   20 |   std::stop_callback cb(tok, f);
      |                               ^
stop.cc:20:31: internal compiler error: Segmentation fault
0xf80c3f crash_signal
        /home/jwakely/src/gcc/gcc/gcc/toplev.c:328
0x85a1b5 add_candidates
        /home/jwakely/src/gcc/gcc/gcc/cp/call.c:5772
0x85efbb add_candidates
        /home/jwakely/src/gcc/gcc/gcc/cp/call.c:4453
0x85efbb perform_overload_resolution
        /home/jwakely/src/gcc/gcc/gcc/cp/call.c:4461
0x8656a2 build_new_function_call(tree_node*, vec<tree_node*, va_gc,
vl_embed>**, int)
        /home/jwakely/src/gcc/gcc/gcc/cp/call.c:4535
0x9c207f do_class_deduction
        /home/jwakely/src/gcc/gcc/gcc/cp/pt.c:28071
0x9c207f do_auto_deduction(tree_node*, tree_node*, tree_node*, int,
auto_deduction_context, tree_node*, int)
        /home/jwakely/src/gcc/gcc/gcc/cp/pt.c:28119
0x8eb86f cp_finish_decl(tree_node*, tree_node*, bool, tree_node*, int)
        /home/jwakely/src/gcc/gcc/gcc/cp/decl.c:7383
0x996e7e cp_parser_init_declarator
        /home/jwakely/src/gcc/gcc/gcc/cp/parser.c:20727
0x976d22 cp_parser_simple_declaration
        /home/jwakely/src/gcc/gcc/gcc/cp/parser.c:13624
0x978ae9 cp_parser_declaration_statement
        /home/jwakely/src/gcc/gcc/gcc/cp/parser.c:13055
0x979733 cp_parser_statement
        /home/jwakely/src/gcc/gcc/gcc/cp/parser.c:11380
0x97a6b8 cp_parser_statement_seq_opt
        /home/jwakely/src/gcc/gcc/gcc/cp/parser.c:11742
0x97a797 cp_parser_compound_statement
        /home/jwakely/src/gcc/gcc/gcc/cp/parser.c:11696
0x993110 cp_parser_function_body
        /home/jwakely/src/gcc/gcc/gcc/cp/parser.c:22866
0x993110 cp_parser_ctor_initializer_opt_and_function_body
        /home/jwakely/src/gcc/gcc/gcc/cp/parser.c:22917
0x996466 cp_parser_function_definition_after_declarator
        /home/jwakely/src/gcc/gcc/gcc/cp/parser.c:28586
0x997273 cp_parser_function_definition_from_specifiers_and_declarator
        /home/jwakely/src/gcc/gcc/gcc/cp/parser.c:28502
0x997273 cp_parser_init_declarator
        /home/jwakely/src/gcc/gcc/gcc/cp/parser.c:20495
0x976d22 cp_parser_simple_declaration
        /home/jwakely/src/gcc/gcc/gcc/cp/parser.c:13624
Please submit a full bug report,
with preprocessed source if appropriate.
Please include the complete backtrace with any bug report.
See <https://gcc.gnu.org/bugs/> for instructions.