[Bug c++/108047] New: ice: unexpected expression of kind implicit_conv_expr

[Bug c++/108047] New: ice: unexpected expression of kind implicit_conv_expr

[dcb314 at hotmail dot com]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=108047

            Bug ID: 108047
           Summary: ice: unexpected expression of kind implicit_conv_expr
           Product: gcc
           Version: 13.0
            Status: UNCONFIRMED
          Severity: normal
          Priority: P3
         Component: c++
          Assignee: unassigned at gcc dot gnu.org
          Reporter: dcb314 at hotmail dot com
  Target Milestone: ---

For this C++ source code:

namespace std {
template <class> class initializer_list;
struct Trans_NS___cxx11_basic_string;
struct vector {
  vector(initializer_list<Trans_NS___cxx11_basic_string>);
};
struct Trans_NS___cxx11_basic_string {
  Trans_NS___cxx11_basic_string(const char *);
};
} // namespace std
constexpr auto kBufVecX = "";
template <typename> struct TestXswap {
  std::vector BuffersIn() { return {kBufVecX}; }
};


does this 

$ ~/gcc/results.20221208.asan.ubsan/bin/g++ -c -w bug866.cc
bug866.cc: In member function ‘std::vector TestXswap< <template-parameter-1-1>
>::BuffersIn()’:
bug866.cc:13:45: internal compiler error: unexpected expression
‘(std::Trans_NS___cxx11_basic_string)kBufVecX’ of kind implicit_conv_expr
   13 |   std::vector BuffersIn() { return {kBufVecX}; }
      |                                             ^
0x7386ae cxx_eval_constant_expression(constexpr_ctx const*, tree_node*,
value_cat, bool*, bool*, tree_node**)
        ../../trunk.d1/gcc/cp/constexpr.cc:8013

It was ok the day before:

$ ~/gcc/results.20221207.asan.ubsan/bin/g++ -c -w bug866.cc
$ 

The git hashes are 3ad0f470c16d5528 and 7410032a772a9e77, a range
of 24 commits.

[Bug c++/108047] ice: unexpected expression of kind implicit_conv_expr

[dcb314 at hotmail dot com]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=108047

--- Comment #1 from David Binderman <dcb314 at hotmail dot com> ---
I am having a go at a git bisect. Trying 892e8c520be37d0a.

[Bug c++/108047] ice: unexpected expression of kind implicit_conv_expr

[dcb314 at hotmail dot com]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=108047

--- Comment #2 from David Binderman <dcb314 at hotmail dot com> ---
That worked fine, so trying 09c91caeb84e7c36.

[Bug c++/108047] ice: unexpected expression of kind implicit_conv_expr

[dcb314 at hotmail dot com]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=108047

David Binderman <dcb314 at hotmail dot com> changed:

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

--- Comment #3 from David Binderman <dcb314 at hotmail dot com> ---
09c91caeb84e7c36 worked fine. 

The remaining interval seems to be [09c91caeb84e7c36..7410032a772a9e77], 
which is six revisions, four of which are by Jason and two unrelated
non-C++.

Jason's best opinion sought.

[Bug c++/108047] ice: unexpected expression of kind implicit_conv_expr

[slyfox at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=108047

Sergei Trofimovich <slyfox at gcc dot gnu.org> changed:

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

--- Comment #4 from Sergei Trofimovich <slyfox at gcc dot gnu.org> ---
Noticed the same build failure on this week's gcc on apache-arrow-cpp-9.0.0.
Extracted small example:

namespace std {
template <class> class initializer_list;
struct Trans_NS___cxx11_basic_string {
  Trans_NS___cxx11_basic_string(const char *);
};
struct vector {
  vector(initializer_list<Trans_NS___cxx11_basic_string>);
};
} // namespace std
void key_value_metadata(std::vector, std::vector);
template <class> void TestWriteDifferentMetadata() {
  key_value_metadata({}, {""});
}

Not sure if it's valid, but gcc-12 still accepts it. Can re-reduce against
clang if needed.

$ ./gcc-git/bin/gcc  -c bug.cc.cc
bug.cc.cc: In function 'void TestWriteDifferentMetadata()':
bug.cc.cc:12:21: internal compiler error: unexpected expression
'(std::Trans_NS___cxx11_basic_string)""' of kind implicit_conv_expr
   12 |   key_value_metadata({}, {""});
      |   ~~~~~~~~~~~~~~~~~~^~~~~~~~~~
0x219cf54 diagnostic_impl(rich_location*, diagnostic_metadata const*, int, char
const*, __va_list_tag (*) [1], diagnostic_t)
        ???:0
0x219dba6 internal_error(char const*, ...)
        ???:0
0x9d4fee cxx_eval_constant_expression(constexpr_ctx const*, tree_node*,
value_cat, bool*, bool*, tree_node**)
        ???:0

[Bug c++/108047] [13 Regression] ICE: unexpected expression of kind implicit_conv_expr since r13-4564-gd081807d8d70e3e8

[marxin at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=108047

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

           What    |Removed                     |Added
----------------------------------------------------------------------------
            Summary|[13 Regression] ice:        |[13 Regression] ICE:
                   |unexpected expression of    |unexpected expression of
                   |kind implicit_conv_expr     |kind implicit_conv_expr
                   |                            |since
                   |                            |r13-4564-gd081807d8d70e3e8
             Status|UNCONFIRMED                 |NEW
                 CC|                            |marxin at gcc dot gnu.org
     Ever confirmed|0                           |1
   Last reconfirmed|                            |2022-12-12

--- Comment #5 from Martin Liška <marxin at gcc dot gnu.org> ---
Started with r13-4564-gd081807d8d70e3e8.

[Bug c++/108047] [13 Regression] ICE: unexpected expression of kind implicit_conv_expr since r13-4564-gd081807d8d70e3e8

[pinskia at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=108047

Andrew Pinski <pinskia at gcc dot gnu.org> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
   Target Milestone|---                         |13.0
           Keywords|                            |ice-on-valid-code

[Bug c++/108047] [13 Regression] ICE: unexpected expression of kind implicit_conv_expr since r13-4564-gd081807d8d70e3e8

[rguenth at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=108047

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

           What    |Removed                     |Added
----------------------------------------------------------------------------
           Priority|P3                          |P1

[Bug c++/108047] [13 Regression] ICE: unexpected expression of kind implicit_conv_expr since r13-4564-gd081807d8d70e3e8

[slyfox at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=108047

--- Comment #6 from Sergei Trofimovich <slyfox at gcc dot gnu.org> ---
Encountered very similar ICE, this time on toml library on this week's gcc-13
master. Reduced it down to the following:

    // $ cat bug.cc
    #include <string>
    #include <vector>
    void format_underline(std::vector<std::string>);

    template <typename>
    void parse_key_value_pair(void) { format_underline({""}); }

$ g++ -c bug.cc
...
bug.cc: In function 'void parse_key_value_pair()':
bug.cc:7:51: internal compiler error: unexpected expression
'(std::__cxx11::basic_string<char>)""' of kind implicit_conv_expr
    7 | void parse_key_value_pair(void) { format_underline({""}); }
      |                                   ~~~~~~~~~~~~~~~~^~~~~~
0x1cbb294 diagnostic_impl(rich_location*, diagnostic_metadata const*, int, char
const*, __va_list_tag (*) [1], diagnostic_t)
        ???:0
0x1cbbee6 internal_error(char const*, ...)
        ???:0
0x79c770 cxx_eval_constant_expression(constexpr_ctx const*, tree_node*,
value_cat, bool*, bool*, tree_node**)
        ???:0
0x7a1572 cxx_eval_outermost_constant_expr(tree_node*, bool, bool, bool, bool,
tree_node*)
        ???:0
0x7a52e6 maybe_constant_init_1(tree_node*, tree_node*, bool, bool)
        ???:0
0x77a767 build_user_type_conversion_1(tree_node*, tree_node*, int, int)
        ???:0

[Bug c++/108047] [13 Regression] ICE: unexpected expression of kind implicit_conv_expr since r13-4564-gd081807d8d70e3e8

[pinskia at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=108047

Andrew Pinski <pinskia at gcc dot gnu.org> changed:

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

--- Comment #7 from Andrew Pinski <pinskia at gcc dot gnu.org> ---
*** Bug 108266 has been marked as a duplicate of this bug. ***

[Bug c++/108047] [13 Regression] ICE: unexpected expression of kind implicit_conv_expr since r13-4564-gd081807d8d70e3e8

[jakub at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=108047

--- Comment #8 from Jakub Jelinek <jakub at gcc dot gnu.org> ---
Created attachment 54201
  --> https://gcc.gnu.org/bugzilla/attachment.cgi?id=54201&action=edit
gcc13-pr108047.patch

My current understanding is that even if nothing in the initializer is
dependent maybe_init_list_as_range will be called again during instantiation
with
!processing_template_decl and because this is just an optimization, I think
it should be fine to do the optimization only if !processing_template_decl.

[Bug c++/108047] [13 Regression] ICE: unexpected expression of kind implicit_conv_expr since r13-4564-gd081807d8d70e3e8

[pinskia at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=108047

Andrew Pinski <pinskia at gcc dot gnu.org> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
                 CC|                            |lukaszcz18 at wp dot pl

--- Comment #9 from Andrew Pinski <pinskia at gcc dot gnu.org> ---
*** Bug 108319 has been marked as a duplicate of this bug. ***

[Bug c++/108047] [13 Regression] ICE: unexpected expression of kind implicit_conv_expr since r13-4564-gd081807d8d70e3e8

[slyfox at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=108047

--- Comment #10 from Sergei Trofimovich <slyfox at gcc dot gnu.org> ---
(In reply to Jakub Jelinek from comment #8)
> Created attachment 54201 [details]
> gcc13-pr108047.patch
> 
> My current understanding is that even if nothing in the initializer is
> dependent maybe_init_list_as_range will be called again during instantiation
> with
> !processing_template_decl and because this is just an optimization, I think
> it should be fine to do the optimization only if !processing_template_decl.

The patch fixes toml library build for me. Thank you!

[Bug c++/108047] [13 Regression] ICE: unexpected expression of kind implicit_conv_expr since r13-4564-gd081807d8d70e3e8

[cvs-commit at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=108047

--- Comment #11 from CVS Commits <cvs-commit at gcc dot gnu.org> ---
The master branch has been updated by Jakub Jelinek <jakub@gcc.gnu.org>:

https://gcc.gnu.org/g:01ea66a6c56e53163d9430f4d87615d570848aa8

commit r13-5075-g01ea66a6c56e53163d9430f4d87615d570848aa8
Author: Jakub Jelinek <jakub@redhat.com>
Date:   Mon Jan 9 23:41:20 2023 +0100

    c++: Only do maybe_init_list_as_range optimization if
!processing_template_decl [PR108047]

    The last testcase in this patch ICEs, because
    maybe_init_list_as_range -> maybe_init_list_as_array
    calls maybe_constant_init in:
      /* Don't do this if the conversion would be constant.  */
      first = maybe_constant_init (first);
      if (TREE_CONSTANT (first))
        return NULL_TREE;
    but maybe_constant_init shouldn't be called when processing_template_decl.
    While we could replace that call with fold_non_dependent_init, my limited
    understanding is that this is an optimization and even if we don't optimize
    it when processing_template_decl, build_user_type_conversion_1 will be
    called again during instantiation with !processing_template_decl if it is
    every instantiated and we can do the optimization only then.

    2023-01-09  Jakub Jelinek  <jakub@redhat.com>

            PR c++/105838
            PR c++/108047
            PR c++/108266
            * call.cc (maybe_init_list_as_range): Always return NULL_TREE if
            processing_template_decl.

            * g++.dg/tree-ssa/initlist-opt2.C: New test.
            * g++.dg/tree-ssa/initlist-opt3.C: New test.

[Bug c++/108047] [13 Regression] ICE: unexpected expression of kind implicit_conv_expr since r13-4564-gd081807d8d70e3e8

[mpolacek at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=108047

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

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

--- Comment #12 from Marek Polacek <mpolacek at gcc dot gnu.org> ---
Fixed?

[Bug c++/108047] [13 Regression] ICE: unexpected expression of kind implicit_conv_expr since r13-4564-gd081807d8d70e3e8

[jakub at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=108047

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

           What    |Removed                     |Added
----------------------------------------------------------------------------
             Status|NEW                         |RESOLVED
         Resolution|---                         |FIXED

--- Comment #13 from Jakub Jelinek <jakub at gcc dot gnu.org> ---
I think so.