[Bug c++/99201] New: ICE in tsubst_copy, at cp/pt.c:16581

[Bug c++/99201] New: ICE in tsubst_copy, at cp/pt.c:16581

[kretz at kde dot org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=99201

            Bug ID: 99201
           Summary: ICE in tsubst_copy, at cp/pt.c:16581
           Product: gcc
           Version: 11.0
            Status: UNCONFIRMED
          Severity: normal
          Priority: P3
         Component: c++
          Assignee: unassigned at gcc dot gnu.org
          Reporter: kretz at kde dot org
  Target Milestone: ---

Testcase (reduced with C-Vise from valid code):

template <class, class... F> void test_values_2arg(int, int, F... fun_pack) {
  [] {}(fun_pack()...);
}
template <typename TestF, typename RefF> auto make_tester(TestF, RefF) {
  return [](auto...) {
    [](auto... vs) {
      if constexpr ([&] { reffun(vs...); })
        ;
    };
  };
}
void test() {
  auto __trans_tmp_1 = make_tester([] {}, [] {});
  test_values_2arg<int>({}, {}, __trans_tmp_1);
}


ice.cpp: In instantiation of 'make_tester<test()::<lambda()>,
test()::<lambda()> >::<lambda(auto:1 ...)> [with auto:1 = {}]':
ice.cpp:2:   required from 'void test_values_2arg(int, int, F ...) [with
<template-parameter-1-1> = int; F = {make_tester<test()::<lambda()>,
test()::<lambda()> >::<lambda(auto:1 ...)>}]'
ice.cpp:14:   required from here
ice.cpp:7: internal compiler error: in tsubst_copy, at cp/pt.c:16581
    7 |       if constexpr ([&] { reffun(vs...); })
      |                                  ^~
0x66f262 tsubst_copy
        /home/mkretz/src/gcc-simd/gcc/cp/pt.c:16581
0x804fae tsubst_copy_and_build(tree_node*, tree_node*, int, tree_node*, bool,
bool)
        /home/mkretz/src/gcc-simd/gcc/cp/pt.c:20719
0x804e6b tsubst_copy_and_build(tree_node*, tree_node*, int, tree_node*, bool,
bool)
        /home/mkretz/src/gcc-simd/gcc/cp/pt.c:19497
0x804e6b tsubst_copy_and_build(tree_node*, tree_node*, int, tree_node*, bool,
bool)
        /home/mkretz/src/gcc-simd/gcc/cp/pt.c:20841
0x816cc4 tsubst_copy_and_build(tree_node*, tree_node*, int, tree_node*, bool,
bool)
        /home/mkretz/src/gcc-simd/gcc/cp/pt.c:19497
0x816cc4 tsubst_expr(tree_node*, tree_node*, int, tree_node*, bool)
        /home/mkretz/src/gcc-simd/gcc/cp/pt.c:19107
0x815dec tsubst_expr(tree_node*, tree_node*, int, tree_node*, bool)
        /home/mkretz/src/gcc-simd/gcc/cp/pt.c:18132
0x815dec tsubst_pack_expansion(tree_node*, tree_node*, int, tree_node*)
        /home/mkretz/src/gcc-simd/gcc/cp/pt.c:13148
0x806acd tsubst_copy_and_build(tree_node*, tree_node*, int, tree_node*, bool,
bool)
        /home/mkretz/src/gcc-simd/gcc/cp/pt.c:20148
0x816cc4 tsubst_copy_and_build(tree_node*, tree_node*, int, tree_node*, bool,
bool)
        /home/mkretz/src/gcc-simd/gcc/cp/pt.c:19497
0x816cc4 tsubst_expr(tree_node*, tree_node*, int, tree_node*, bool)
        /home/mkretz/src/gcc-simd/gcc/cp/pt.c:19107
0x817cee tsubst_expr(tree_node*, tree_node*, int, tree_node*, bool)
        /home/mkretz/src/gcc-simd/gcc/cp/pt.c:18132
0x817cee tsubst_expr(tree_node*, tree_node*, int, tree_node*, bool)
        /home/mkretz/src/gcc-simd/gcc/cp/pt.c:18177
0x818893 tsubst_expr(tree_node*, tree_node*, int, tree_node*, bool)
        /home/mkretz/src/gcc-simd/gcc/cp/pt.c:18132
0x818893 tsubst_expr(tree_node*, tree_node*, int, tree_node*, bool)
        /home/mkretz/src/gcc-simd/gcc/cp/pt.c:18147
0x8177da tsubst_expr(tree_node*, tree_node*, int, tree_node*, bool)
        /home/mkretz/src/gcc-simd/gcc/cp/pt.c:18132
0x8177da tsubst_expr(tree_node*, tree_node*, int, tree_node*, bool)
        /home/mkretz/src/gcc-simd/gcc/cp/pt.c:18498
0x8177da tsubst_expr(tree_node*, tree_node*, int, tree_node*, bool)
        /home/mkretz/src/gcc-simd/gcc/cp/pt.c:18132
0x8177da tsubst_expr(tree_node*, tree_node*, int, tree_node*, bool)
        /home/mkretz/src/gcc-simd/gcc/cp/pt.c:18498
0x81f84b tsubst_expr(tree_node*, tree_node*, int, tree_node*, bool)
        /home/mkretz/src/gcc-simd/gcc/cp/pt.c:18132

[Bug c++/99201] [8/9/10/11 Regression] ICE in tsubst_copy, at cp/pt.c:16581

[mpolacek at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=99201

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

           What    |Removed                     |Added
----------------------------------------------------------------------------
   Target Milestone|---                         |8.5
                 CC|                            |mpolacek at gcc dot gnu.org
            Summary|ICE in tsubst_copy, at      |[8/9/10/11 Regression] ICE
                   |cp/pt.c:16581               |in tsubst_copy, at
                   |                            |cp/pt.c:16581
             Status|UNCONFIRMED                 |NEW
     Ever confirmed|0                           |1
   Last reconfirmed|                            |2021-02-22

--- Comment #1 from Marek Polacek <mpolacek at gcc dot gnu.org> ---
Started with r273944.  The reduced test seems to be invalid.

[Bug c++/99201] [8/9/10/11 Regression] ICE in tsubst_copy, at cp/pt.c:16581

[jakub at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=99201

Jakub Jelinek <jakub at gcc dot gnu.org> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
                 CC|                            |jakub at gcc dot gnu.org

--- Comment #2 from Jakub Jelinek <jakub at gcc dot gnu.org> ---
If r273943 accepted it, perhaps we need another reduction that will result in
no errors with that revision and in that ICE (plus no further errors) with
r273944.

[Bug c++/99201] [8/9/10/11 Regression] ICE in tsubst_copy, at cp/pt.c:16581

[kretz at kde dot org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=99201

--- Comment #3 from Matthias Kretz (Vir) <kretz at kde dot org> ---
I'll try to find a better reduction.

[Bug c++/99201] [8/9/10/11 Regression] ICE in tsubst_copy, at cp/pt.c:16581

[kretz at kde dot org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=99201

--- Comment #4 from Matthias Kretz (Vir) <kretz at kde dot org> ---
Manual reduction which fails with 8-11 and compiles ok with 7:

template <class V, class... F>
  void
  test_values_2arg(F&&... fun_pack)
  {
    (fun_pack(V(), V()), ...);
  }

template <typename TestF, typename RefF>
  auto
  make_tester(const TestF& testfun, const RefF& reffun)
  {
    return [=](auto... inputs) {
      auto totest = reffun(inputs...);
      using R = decltype(totest);
      auto&& expected = [&](const auto&... vs) {
        if constexpr (sizeof(R) > 0)
          return [&](auto i) { return reffun(vs[i]...); }(0);
        else
          return [&](auto i) { return reffun(vs[i]...); }(0);
      };
    };
  }
template <typename T> T foo(T, T) {
}
int main()
{
  test_values_2arg<double>(make_tester(
                             [](auto... xs) { return foo(xs...); },
                             [](auto... xs) { return foo(xs...); }));
  return 0;
}

[Bug c++/99201] [8/9/10/11 Regression] ICE in tsubst_copy, at cp/pt.c:16581

[rguenth at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=99201

Richard Biener <rguenth at gcc dot gnu.org> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
           Keywords|                            |ice-on-valid-code
           Priority|P3                          |P2

[Bug c++/99201] [8/9/10/11 Regression] ICE in tsubst_copy, at cp/pt.c:16581

[kretz at kde dot org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=99201

--- Comment #5 from Matthias Kretz (Vir) <kretz at kde dot org> ---
I reduced it some more:

template <typename RefF>
  auto
  make_tester(const RefF& reffun)
  {
    return [=](auto in) {
      auto&& expected = [&](const auto&... vs) {
        if constexpr (sizeof(in) > 0)
          return [&](auto i) { return reffun(vs[i]...); }(0);
        else
          return [&](auto i) { return reffun(vs[i]...); }(0);
      };
    };
  }

int main()
{
  make_tester([](auto x) { return x; })(0);
  return 0;
}

[Bug c++/99201] [8/9/10/11 Regression] ICE in tsubst_copy, at cp/pt.c:16581 since r8-7613-g1456e764105702a0

[marxin at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=99201

Martin Liška <marxin at gcc dot gnu.org> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
                 CC|                            |jason at gcc dot gnu.org,
                   |                            |marxin at gcc dot gnu.org
            Summary|[8/9/10/11 Regression] ICE  |[8/9/10/11 Regression] ICE
                   |in tsubst_copy, at          |in tsubst_copy, at
                   |cp/pt.c:16581               |cp/pt.c:16581 since
                   |                            |r8-7613-g1456e764105702a0

--- Comment #6 from Martin Liška <marxin at gcc dot gnu.org> ---
Started with r8-7613-g1456e764105702a0.

[Bug c++/99201] [8/9/10/11 Regression] ICE in tsubst_copy, at cp/pt.c:16581 since r8-7613-g1456e764105702a0

[jason at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=99201

Jason Merrill <jason at gcc dot gnu.org> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
             Status|NEW                         |ASSIGNED
           Assignee|unassigned at gcc dot gnu.org      |jason at gcc dot gnu.org

[Bug c++/99201] [8/9/10/11 Regression] ICE in tsubst_copy, at cp/pt.c:16581 since r8-7613-g1456e764105702a0

[cvs-commit at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=99201

--- Comment #7 from CVS Commits <cvs-commit at gcc dot gnu.org> ---
The master branch has been updated by Jason Merrill <jason@gcc.gnu.org>:

https://gcc.gnu.org/g:a99a7b0afe9a1f6f866e25b8572856ae8c1d3f8d

commit r11-7985-ga99a7b0afe9a1f6f866e25b8572856ae8c1d3f8d
Author: Jason Merrill <jason@redhat.com>
Date:   Sun Apr 4 01:01:56 2021 -0400

    c++: constexpr if and nested generic lambda [PR99201]

    When building up *_EXTRA_ARGS for a constexpr if or pack expansion, we need
    to walk into the body of a lambda to find all the local_specializations
that
    we need to remember, like we do in find_parameter_packs_r.

    gcc/cp/ChangeLog:

            PR c++/99201
            * pt.c (class el_data): Add visited field.
            (extract_local_specs): Pass it to cp_walk_tree.
            (extract_locals_r): Walk into the body of a lambda.

    gcc/testsuite/ChangeLog:

            PR c++/99201
            * g++.dg/cpp1z/constexpr-if-lambda4.C: New test.

[Bug c++/99201] [8/9/10 Regression] ICE in tsubst_copy, at cp/pt.c:16581 since r8-7613-g1456e764105702a0

[jason at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=99201

Jason Merrill <jason at gcc dot gnu.org> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
            Summary|[8/9/10/11 Regression] ICE  |[8/9/10 Regression] ICE in
                   |in tsubst_copy, at          |tsubst_copy, at
                   |cp/pt.c:16581 since         |cp/pt.c:16581 since
                   |r8-7613-g1456e764105702a0   |r8-7613-g1456e764105702a0

--- Comment #8 from Jason Merrill <jason at gcc dot gnu.org> ---
Fixed for 11 so far.

[Bug c++/99201] [9/10 Regression] ICE in tsubst_copy, at cp/pt.c:16581 since r8-7613-g1456e764105702a0

[jakub at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=99201

Jakub Jelinek <jakub at gcc dot gnu.org> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
   Target Milestone|8.5                         |9.4

--- Comment #9 from Jakub Jelinek <jakub at gcc dot gnu.org> ---
GCC 8 branch is being closed.

[Bug c++/99201] [9/10 Regression] ICE in tsubst_copy, at cp/pt.c:16581 since r8-7613-g1456e764105702a0

[cvs-commit at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=99201

--- Comment #10 from CVS Commits <cvs-commit at gcc dot gnu.org> ---
The releases/gcc-10 branch has been updated by Jason Merrill
<jason@gcc.gnu.org>:

https://gcc.gnu.org/g:7c365bb1462a7a9dadf9b8f8668a0c832b18056c

commit r10-9844-g7c365bb1462a7a9dadf9b8f8668a0c832b18056c
Author: Jason Merrill <jason@redhat.com>
Date:   Sun Apr 4 01:01:56 2021 -0400

    c++: constexpr if and nested generic lambda [PR99201]

    When building up *_EXTRA_ARGS for a constexpr if or pack expansion, we need
    to walk into the body of a lambda to find all the local_specializations
that
    we need to remember, like we do in find_parameter_packs_r.

    gcc/cp/ChangeLog:

            PR c++/99201
            * pt.c (class el_data): Add visited field.
            (extract_local_specs): Pass it to cp_walk_tree.
            (extract_locals_r): Walk into the body of a lambda.

    gcc/testsuite/ChangeLog:

            PR c++/99201
            * g++.dg/cpp1z/constexpr-if-lambda4.C: New test.

[Bug c++/99201] [9/10 Regression] ICE in tsubst_copy, at cp/pt.c:16581 since r8-7613-g1456e764105702a0

[rguenth at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=99201

Richard Biener <rguenth at gcc dot gnu.org> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
   Target Milestone|9.4                         |9.5

--- Comment #11 from Richard Biener <rguenth at gcc dot gnu.org> ---
GCC 9.4 is being released, retargeting bugs to GCC 9.5.

[Bug c++/99201] [9 Regression] ICE in tsubst_copy, at cp/pt.c:16581 since r8-7613-g1456e764105702a0

[rguenth at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=99201

Richard Biener <rguenth at gcc dot gnu.org> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
             Status|ASSIGNED                    |RESOLVED
   Target Milestone|9.5                         |10.4
      Known to fail|                            |9.5.0
         Resolution|---                         |FIXED

--- Comment #12 from Richard Biener <rguenth at gcc dot gnu.org> ---
Fixed for GCC 10.4.