[Bug c++/88325] New: ICE on (invalid) C++ code when compiled with -std=c++2a: in make_typename_type, at cp/decl.c:3816

[su at cs dot ucdavis.edu]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=88325

            Bug ID: 88325
           Summary: ICE on (invalid) C++ code when compiled with
                    -std=c++2a: in make_typename_type, at cp/decl.c:3816
           Product: gcc
           Version: unknown
            Status: UNCONFIRMED
          Severity: normal
          Priority: P3
         Component: c++
          Assignee: unassigned at gcc dot gnu.org
          Reporter: su at cs dot ucdavis.edu
  Target Milestone: ---

This appears to be a recent regression.

$ g++tk -v
Using built-in specs.
COLLECT_GCC=g++tk
COLLECT_LTO_WRAPPER=/home/su/software/tmp/gcc/gcc-trunk/libexec/gcc/x86_64-pc-linux-gnu/9.0.0/lto-wrapper
Target: x86_64-pc-linux-gnu
Configured with: ../gcc-source-trunk/configure --enable-languages=c,c++,lto
--prefix=/home/su/software/tmp/gcc/gcc-trunk --disable-bootstrap
Thread model: posix
gcc version 9.0.0 20181203 (experimental) [trunk revision 266735] (GCC) 
$ 
$ g++tk -std=c++2a -c tmp.cpp
tmp.cpp:6:34: internal compiler error: in make_typename_type, at cp/decl.c:3816
    6 | template < typename T > A < T >::A < T > () {}
      |                                  ^~~~~~~
0x7573fd make_typename_type(tree_node*, tree_node*, tag_types, int)
        ../../gcc-source-trunk/gcc/cp/decl.c:3816
0x80a9ac cp_parser_class_name
        ../../gcc-source-trunk/gcc/cp/parser.c:22970
0x80ae81 cp_parser_type_name
        ../../gcc-source-trunk/gcc/cp/parser.c:17837
0x7f4334 cp_parser_simple_type_specifier
        ../../gcc-source-trunk/gcc/cp/parser.c:17697
0x8037b5 cp_parser_type_specifier
        ../../gcc-source-trunk/gcc/cp/parser.c:17336
0x80dbc7 cp_parser_decl_specifier_seq
        ../../gcc-source-trunk/gcc/cp/parser.c:13986
0x81a7e8 cp_parser_single_declaration
        ../../gcc-source-trunk/gcc/cp/parser.c:27828
0x81abbc cp_parser_template_declaration_after_parameters
        ../../gcc-source-trunk/gcc/cp/parser.c:27507
0x81b6cd cp_parser_explicit_template_declaration
        ../../gcc-source-trunk/gcc/cp/parser.c:27754
0x81b6cd cp_parser_template_declaration_after_export
        ../../gcc-source-trunk/gcc/cp/parser.c:27772
0x823179 cp_parser_declaration
        ../../gcc-source-trunk/gcc/cp/parser.c:13055
0x821e5e cp_parser_translation_unit
        ../../gcc-source-trunk/gcc/cp/parser.c:4688
0x821e5e c_parse_file()
        ../../gcc-source-trunk/gcc/cp/parser.c:40806
0x979bfa c_common_parse_file()
        ../../gcc-source-trunk/gcc/c-family/c-opts.c:1151
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.
$ 


--------------------------------------------------


template < typename > struct A
{
  template < typename > A ();
};

template < typename T > A < T >::A < T > () {}