[Bug c++/96676] New: Segmentation fault on parsing simple variadic template function call

[Bug c++/96676] New: Segmentation fault on parsing simple variadic template function call

[ivan.leonov.d at yandex dot ru]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=96676

            Bug ID: 96676
           Summary: Segmentation fault on parsing simple variadic template
                    function call
           Product: gcc
           Version: 11.0
            Status: UNCONFIRMED
          Severity: normal
          Priority: P3
         Component: c++
          Assignee: unassigned at gcc dot gnu.org
          Reporter: ivan.leonov.d at yandex dot ru
  Target Milestone: ---

Sample code:

template < typename T, typename... TYPES >
struct A {
    template < TYPES... types >
    void Get() { }
};

void f() {}

int main() {
    A<int, decltype(&f)> a;
    a.Get<&f>();
}


Error and Backtrace:

prog.cc: In function 'int main()':
prog.cc:13:15: internal compiler error: Segmentation fault
   13 |     a.Get<&f>();
      |               ^
0xc026af crash_signal
        ../../source/gcc/toplev.c:327
0x73a995 tsubst_pack_expansion(tree_node*, tree_node*, int, tree_node*)
        ../../source/gcc/cp/pt.c:12871
0x7356d1 coerce_template_parameter_pack
        ../../source/gcc/cp/pt.c:8538
0x7356d1 coerce_template_parms
        ../../source/gcc/cp/pt.c:8830
0x747bc8 fn_type_unification(tree_node*, tree_node*, tree_node*, tree_node*
const*, unsigned int, tree_node*, unification_kind_t, int, conversion**, bool,
bool)
        ../../source/gcc/cp/pt.c:21078
0x619282 add_template_candidate_real
        ../../source/gcc/cp/call.c:3417
0x6199bc add_template_candidate
        ../../source/gcc/cp/call.c:3502
0x6199bc add_candidates
        ../../source/gcc/cp/call.c:5883
0x61a9cc add_candidates
        ../../source/gcc/cp/call.c:5798
0x61a9cc build_new_method_call_1
        ../../source/gcc/cp/call.c:10271
0x61b6ff build_new_method_call(tree_node*, tree_node*, vec<tree_node*, va_gc,
vl_embed>**, tree_node*, int, tree_node**, int)
        ../../source/gcc/cp/call.c:10478
0x6fcdd7 cp_parser_postfix_expression
        ../../source/gcc/cp/parser.c:7513
0x6dfa9a cp_parser_binary_expression
        ../../source/gcc/cp/parser.c:9641
0x6e13de cp_parser_assignment_expression
        ../../source/gcc/cp/parser.c:9946
0x6e16e2 cp_parser_expression
        ../../source/gcc/cp/parser.c:10114
0x6e41b8 cp_parser_expression_statement
        ../../source/gcc/cp/parser.c:11774
0x6eef10 cp_parser_statement
        ../../source/gcc/cp/parser.c:11570
0x6f076d cp_parser_statement_seq_opt
        ../../source/gcc/cp/parser.c:11921
0x6f0820 cp_parser_compound_statement
        ../../source/gcc/cp/parser.c:11871
0x7078da cp_parser_function_body
        ../../source/gcc/cp/parser.c:23170

[Bug c++/96676] Segmentation fault on parsing simple variadic template function call

[ivan.leonov.d at yandex dot ru]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=96676

--- Comment #1 from Ivan Leonov <ivan.leonov.d at yandex dot ru> ---
Output of gcc -v:

Using built-in specs.
COLLECT_GCC=/opt/wandbox/gcc-head/bin/g++
COLLECT_LTO_WRAPPER=/opt/wandbox/gcc-head/libexec/gcc/x86_64-pc-linux-gnu/11.0.0/lto-wrapper
Target: x86_64-pc-linux-gnu
Configured with: ../source/configure --prefix=/opt/wandbox/gcc-head
--enable-languages=c,c++ --disable-multilib --without-ppl --without-cloog-ppl
--enable-checking=release --disable-nls --enable-lto
LDFLAGS=-Wl,-rpath,/opt/wandbox/gcc-head/lib,-rpath,/opt/wandbox/gcc-head/lib64,-rpath,/opt/wandbox/gcc-head/lib32
Thread model: posix
Supported LTO compression algorithms: zlib
gcc version 11.0.0 20200816 (experimental) (GCC) 
COLLECT_GCC_OPTIONS='-o' 'prog.exe' '-I' '/opt/wandbox/boost-sml/include' '-I'
'/opt/wandbox/boost-di/include' '-I' '/opt/wandbox/range-v3/include' '-I'
'/opt/wandbox/nlohmann-json/include' '-I' '/opt/wandbox/cmcstl2/include' '-I'
'/opt/wandbox/te/include' '-std=gnu++20' '-Wall' '-Wextra' '-I'
'/opt/wandbox/boost-1.68.0/gcc-head/include'
'-L/opt/wandbox/boost-1.68.0/gcc-head/lib' '-v' '-shared-libgcc'
'-mtune=generic' '-march=x86-64'
 /opt/wandbox/gcc-head/libexec/gcc/x86_64-pc-linux-gnu/11.0.0/cc1plus -quiet -v
-I /opt/wandbox/boost-sml/include -I /opt/wandbox/boost-di/include -I
/opt/wandbox/range-v3/include -I /opt/wandbox/nlohmann-json/include -I
/opt/wandbox/cmcstl2/include -I /opt/wandbox/te/include -I
/opt/wandbox/boost-1.68.0/gcc-head/include -imultiarch x86_64-linux-gnu
-D_GNU_SOURCE prog.cc -quiet -dumpbase prog.cc -dumpbase-ext .cc -mtune=generic
-march=x86-64 -Wall -Wextra -std=gnu++20 -version -o /tmp/ccDLpOFA.s
GNU C++20 (GCC) version 11.0.0 20200816 (experimental) (x86_64-pc-linux-gnu)
        compiled by GNU C version 11.0.0 20200816 (experimental), GMP version
6.1.0, MPFR version 3.1.4, MPC version 1.0.3, isl version none
GGC heuristics: --param ggc-min-expand=100 --param ggc-min-heapsize=131072
ignoring nonexistent directory "/usr/local/include/x86_64-linux-gnu"
ignoring nonexistent directory "/usr/local/include"
ignoring nonexistent directory
"/opt/wandbox/gcc-head/lib/gcc/x86_64-pc-linux-gnu/11.0.0/../../../../x86_64-pc-linux-gnu/include"
#include "..." search starts here:
#include <...> search starts here:
 /opt/wandbox/boost-sml/include
 /opt/wandbox/boost-di/include
 /opt/wandbox/range-v3/include
 /opt/wandbox/nlohmann-json/include
 /opt/wandbox/cmcstl2/include
 /opt/wandbox/te/include
 /opt/wandbox/boost-1.68.0/gcc-head/include

/opt/wandbox/gcc-head/lib/gcc/x86_64-pc-linux-gnu/11.0.0/../../../../include/c++/11.0.0

/opt/wandbox/gcc-head/lib/gcc/x86_64-pc-linux-gnu/11.0.0/../../../../include/c++/11.0.0/x86_64-pc-linux-gnu

/opt/wandbox/gcc-head/lib/gcc/x86_64-pc-linux-gnu/11.0.0/../../../../include/c++/11.0.0/backward
 /opt/wandbox/gcc-head/lib/gcc/x86_64-pc-linux-gnu/11.0.0/include
 /opt/wandbox/gcc-head/include
 /opt/wandbox/gcc-head/lib/gcc/x86_64-pc-linux-gnu/11.0.0/include-fixed
 /usr/include/x86_64-linux-gnu
 /usr/include
End of search list.
GNU C++20 (GCC) version 11.0.0 20200816 (experimental) (x86_64-pc-linux-gnu)
        compiled by GNU C version 11.0.0 20200816 (experimental), GMP version
6.1.0, MPFR version 3.1.4, MPC version 1.0.3, isl version none
GGC heuristics: --param ggc-min-expand=100 --param ggc-min-heapsize=131072
Compiler executable checksum: 3d112d3862b6c6b3c098fd9068684321

[Bug c++/96676] Segmentation fault on parsing simple variadic template function call

[mpolacek at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=96676

Marek Polacek <mpolacek at gcc dot gnu.org> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
             Status|UNCONFIRMED                 |RESOLVED
         Resolution|---                         |DUPLICATE
                 CC|                            |mpolacek at gcc dot gnu.org

--- Comment #2 from Marek Polacek <mpolacek at gcc dot gnu.org> ---
Thanks for the report.  I think it's a dup.

*** This bug has been marked as a duplicate of bug 84796 ***

[Bug c++/96676] Segmentation fault on parsing simple variadic template function call

[mpolacek at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=96676

Marek Polacek <mpolacek at gcc dot gnu.org> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
             Status|RESOLVED                    |NEW
   Last reconfirmed|                            |2020-08-18
     Ever confirmed|0                           |1
         Resolution|DUPLICATE                   |---

--- Comment #3 from Marek Polacek <mpolacek at gcc dot gnu.org> ---
Actually, it probably isn't.