[Bug c++/98899] New: ICE: Illegal instruction: 4 "error: could not convert '<unparsed>' from ''<invalid tree code>'" on macOS

[Bug c++/98899] New: ICE: Illegal instruction: 4 "error: could not convert '<unparsed>' from ''<invalid tree code>'" on macOS

[akim.demaille at gmail dot com]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=98899

            Bug ID: 98899
           Summary: ICE: Illegal instruction: 4 "error: could not convert
                    '<unparsed>' from ''<invalid tree code>'" on macOS
           Product: gcc
           Version: 10.2.0
            Status: UNCONFIRMED
          Severity: normal
          Priority: P3
         Component: c++
          Assignee: unassigned at gcc dot gnu.org
          Reporter: akim.demaille at gmail dot com
  Target Milestone: ---

G++ behaves randomly on this issue.  Sometimes it gives me an error message
that does not seem to be meant for the user:

```
$ g++-mp-10 simple.cc -Wall -c
simple.cc: In instantiation of
'yy::parser::basic_symbol<Base>::basic_symbol(typename Base::kind_type, int&&)
[with Base = yy::parser::by_kind; typename Base::kind_type =
yy::parser::token::token_kind_type]':
simple.cc:653:53:   required from here
simple.cc:484:7: error: could not convert '<unparsed>' from ''<invalid tree
code>' not supported by dump_type<type error>' to 'bool'
  484 |       basic_symbol (typename Base::kind_type t, int&& v)
      |       ^~~~~~~~~~~~
simple.cc: In instantiation of
'yy::parser::basic_symbol<Base>::basic_symbol(typename Base::kind_type,
std::string&&) [with Base = yy::parser::by_kind; typename Base::kind_type =
yy::parser::token::token_kind_type; std::string =
std::__cxx11::basic_string<char>]':
simple.cc:661:53:   required from here
simple.cc:497:7: error: could not convert '<unparsed>' from ''<invalid tree
code>' not supported by dump_type<type error>' to 'bool'
  497 |       basic_symbol (typename Base::kind_type t, std::string&& v)
      |       ^~~~~~~~~~~~
simple.cc: In instantiation of
'yy::parser::basic_symbol<Base>::basic_symbol(yy::parser::basic_symbol<Base>&&)
[with Base = yy::parser::by_kind]':
simple.cc:722:41:   required from here
simple.cc:438:7: error: could not convert '<unparsed>' from ''<invalid tree
code>' not supported by dump_type<type error>' to 'bool'
  438 |       basic_symbol (basic_symbol&& that)
      |       ^~~~~~~~~~~~
```

and sometimes it crashes:

```
$ g++-mp-10 simple.cc -Wall -c
simple.cc: In instantiation of
'yy::parser::basic_symbol<Base>::basic_symbol(typename Base::kind_type, int&&)
[with Base = yy::parser::by_kind; typename Base::kind_type =
yy::parser::token::token_kind_type]':
simple.cc:653:53:   required from here
simple.cc:484:7: internal compiler error: Illegal instruction: 4
  484 |       basic_symbol (typename Base::kind_type t, int&& v)
      |       ^~~~~~~~~~~~
libbacktrace could not find executable to open
Please submit a full bug report,
with preprocessed source if appropriate.
See <https://trac.macports.org/newticket> for instructions.
```

I have tried to reduce the example, but it seems to be quite touchy.

This is:

```
$ g++-mp-10 --version
g++-mp-10 (MacPorts gcc10 10.2.0_4) 10.2.0
Copyright (C) 2020 Free Software Foundation, Inc.
This is free software; see the source for copying conditions.  There is NO
warranty; not even for MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.
```

FWIW, clang++ 11 accepts this source.

(I have problems trying to add the attachment, will try when the issue is
created.)

[Bug c++/98899] ICE: Illegal instruction: 4 "error: could not convert '<unparsed>' from ''<invalid tree code>'" on macOS

[akim.demaille at gmail dot com]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=98899

--- Comment #1 from Akim Demaille <akim.demaille at gmail dot com> ---
Created attachment 50093
  --> https://gcc.gnu.org/bugzilla/attachment.cgi?id=50093&action=edit
simple.cc

The source that causes the crash.

[Bug c++/98899] ICE: Illegal instruction: 4 "error: could not convert '<unparsed>' from ''<invalid tree code>'" on macOS

[akim.demaille at gmail dot com]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=98899

--- Comment #2 from Akim Demaille <akim.demaille at gmail dot com> ---
Created attachment 50094
  --> https://gcc.gnu.org/bugzilla/attachment.cgi?id=50094&action=edit
simple.ii

simple.cc preprocessed

[Bug c++/98899] [10/11 Regression] ICE in tsubst_copy, at cp/pt.c:16198 since r10-1280-g78f7607db4c53f8c

[marxin at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=98899

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

           What    |Removed                     |Added
----------------------------------------------------------------------------
   Target Milestone|---                         |10.3
             Status|UNCONFIRMED                 |NEW
            Summary|ICE: Illegal instruction: 4 |[10/11 Regression] ICE in
                   |"error: could not convert   |tsubst_copy, at
                   |'<unparsed>' from           |cp/pt.c:16198 since
                   |''<invalid tree code>'" on  |r10-1280-g78f7607db4c53f8c
                   |macOS                       |
                 CC|                            |marxin at gcc dot gnu.org,
                   |                            |mpolacek at gcc dot gnu.org
   Last reconfirmed|                            |2021-02-01
           Keywords|                            |ice-on-valid-code
     Ever confirmed|0                           |1
      Known to work|                            |9.3.0
      Known to fail|                            |10.2.0, 11.0

--- Comment #3 from Martin Liška <marxin at gcc dot gnu.org> ---
Thank you for the bug report.

Reduce test-case:

$ cat pr98899.ii
template <int __v> struct integral_constant {
  static constexpr int value = __v;
};
template <typename> struct conditional;
template <typename...> struct __and_;
template <typename _B1, typename _B2>
struct __and_<_B1, _B2> : conditional<_B1>::type {};
template <typename...>
struct __is_nt_constructible_impl : integral_constant<0> {};
template <typename... _Args>
struct is_nothrow_constructible
    : __and_<int, __is_nt_constructible_impl<_Args...>> {};
template <typename> struct conditional {
  typedef __is_nt_constructible_impl<> type;
};
class locale {
  struct token {
    enum {} typedef yytokentype;
  };
  template <typename Base> struct basic_symbol {
    basic_symbol(typename Base::kind_type,
                 int) noexcept(is_nothrow_constructible<>::value);
  };
  struct by_kind {
    typedef token::yytokentype kind_type;
  };
  struct symbol_type : basic_symbol<by_kind> {
    int symbol_type_v;
    symbol_type() : basic_symbol(token::yytokentype(), symbol_type_v) {}
  };
};

$ g++ pr98899.ii -c -Werror
pr98899.ii: In instantiation of
‘locale::basic_symbol<Base>::basic_symbol(typename Base::kind_type, int) [with
Base = locale::by_kind; typename Base::kind_type =
locale::token::yytokentype]’:
pr98899.ii:29:69:   required from here
pr98899.ii:21:5: internal compiler error: in tsubst_copy, at cp/pt.c:17205
   21 |     basic_symbol(typename Base::kind_type,
      |     ^~~~~~~~~~~~
0x6e0e47 tsubst_copy
        /home/marxin/Programming/gcc/gcc/cp/pt.c:17205
0xb24f7e tsubst_copy_and_build(tree_node*, tree_node*, int, tree_node*, bool,
bool)
        /home/marxin/Programming/gcc/gcc/cp/pt.c:20789
0xb28755 maybe_instantiate_noexcept(tree_node*, int)
        /home/marxin/Programming/gcc/gcc/cp/pt.c:25592
0xb2833c maybe_instantiate_noexcept(tree_node*, int)
        /home/marxin/Programming/gcc/gcc/cp/pt.c:25535
0xa194ca mark_used(tree_node*, int)
        /home/marxin/Programming/gcc/gcc/cp/decl2.c:5610
0x9623a5 build_over_call
        /home/marxin/Programming/gcc/gcc/cp/call.c:9351
0x95f722 build_new_method_call_1
        /home/marxin/Programming/gcc/gcc/cp/call.c:10637
0x95f722 build_new_method_call(tree_node*, tree_node*, vec<tree_node*, va_gc,
vl_embed>**, tree_node*, int, tree_node**, int)
        /home/marxin/Programming/gcc/gcc/cp/call.c:10712
0x960a86 build_special_member_call(tree_node*, tree_node*, vec<tree_node*,
va_gc, vl_embed>**, tree_node*, int, int)
        /home/marxin/Programming/gcc/gcc/cp/call.c:10113
0xa385ca expand_default_init
        /home/marxin/Programming/gcc/gcc/cp/init.c:1983
0xa385ca expand_aggr_init_1
        /home/marxin/Programming/gcc/gcc/cp/init.c:2098
0xa3fb1b emit_mem_initializers(tree_node*)
        /home/marxin/Programming/gcc/gcc/cp/init.c:1354
0xaf39b9 cp_parser_mem_initializer_list
        /home/marxin/Programming/gcc/gcc/cp/parser.c:15907
0xaf39b9 cp_parser_ctor_initializer_opt
        /home/marxin/Programming/gcc/gcc/cp/parser.c:15815
0xaf39b9 cp_parser_ctor_initializer_opt_and_function_body
        /home/marxin/Programming/gcc/gcc/cp/parser.c:24027
0xaf511a cp_parser_function_definition_after_declarator
        /home/marxin/Programming/gcc/gcc/cp/parser.c:29938
0xaf5624 cp_parser_late_parsing_for_member
        /home/marxin/Programming/gcc/gcc/cp/parser.c:30845
0xacea63 cp_parser_class_specifier_1
        /home/marxin/Programming/gcc/gcc/cp/parser.c:25104
0xacfa7b cp_parser_class_specifier
        /home/marxin/Programming/gcc/gcc/cp/parser.c:25128
0xacfa7b cp_parser_type_specifier
        /home/marxin/Programming/gcc/gcc/cp/parser.c:18381
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.

[Bug c++/98899] [10/11 Regression] ICE in tsubst_copy, at cp/pt.c:16198 since r10-1280-g78f7607db4c53f8c

[ppalka at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=98899

Patrick Palka <ppalka at gcc dot gnu.org> changed:

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

--- Comment #4 from Patrick Palka <ppalka at gcc dot gnu.org> ---
FWIW, here's a more minimal testcase:

template <int __v> struct integral_constant {
  static constexpr int value = __v;
};
struct _Bit_iterator_base {
  template <class> struct basic_symbol {
    basic_symbol() noexcept(integral_constant<false>::value);
  };
  struct symbol_type : basic_symbol<int> {
    symbol_type() : basic_symbol() {}
  };
};

[Bug c++/98899] [10/11 Regression] ICE in tsubst_copy, at cp/pt.c:16198 since r10-1280-g78f7607db4c53f8c

[mpolacek at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=98899

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

           What    |Removed                     |Added
----------------------------------------------------------------------------
           Priority|P3                          |P2
           Assignee|unassigned at gcc dot gnu.org      |mpolacek at gcc dot gnu.org
             Status|NEW                         |ASSIGNED

--- Comment #5 from Marek Polacek <mpolacek at gcc dot gnu.org> ---
Mine.

[Bug c++/98899] [10/11 Regression] ICE in tsubst_copy, at cp/pt.c:16198 since r10-1280-g78f7607db4c53f8c

[cvs-commit at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=98899

--- Comment #6 from CVS Commits <cvs-commit at gcc dot gnu.org> ---
The master branch has been updated by Marek Polacek <mpolacek@gcc.gnu.org>:

https://gcc.gnu.org/g:25fdd0d6df44044a8b505e6fcd07270e2e279b06

commit r11-7065-g25fdd0d6df44044a8b505e6fcd07270e2e279b06
Author: Marek Polacek <polacek@redhat.com>
Date:   Mon Feb 1 23:30:05 2021 -0500

    c++: ICE with late parsing of noexcept in nested class [PR98899]

    Here we crash with a noexcept-specifier in a nested template class,
    because my handling of such deferred-parse noexcept-specifiers was
    gronked when we need to instantiate a DEFERRED_PARSE before it was
    actually parsed at the end of the outermost class.

    In

      struct S {
        template<class> struct B {
          B() noexcept(noexcept(x));
          int x;
        };
        struct A : B<int> {
          A() : B() {}
        };
      };

    we call complete_type for B<int> which triggers tsubsting S::B<int>::B()
    whose noexcept-specifier still contains a DEFERRED_PARSE.  The trick is
    to stash such noexcept-specifiers into DEFPARSE_INSTANTIATIONS so that
    we can replace it later when we've finally parsed all deferred
    noexcept-specifiers.

    In passing, fix missing usage of UNPARSED_NOEXCEPT_SPEC_P.

    gcc/cp/ChangeLog:

            PR c++/98899
            * parser.c (cp_parser_class_specifier_1): Use any possible
            DEFPARSE_INSTANTIATIONS to update DEFERRED_NOEXCEPT_PATTERN.
            (cp_parser_save_noexcept): Initialize DEFPARSE_INSTANTIATIONS.
            * pt.c (tsubst_exception_specification): Stash new_specs into
            DEFPARSE_INSTANTIATIONS.
            * tree.c (fixup_deferred_exception_variants): Use
            UNPARSED_NOEXCEPT_SPEC_P.

    gcc/testsuite/ChangeLog:

            PR c++/98899
            * g++.dg/cpp0x/noexcept65.C: New test.

[Bug c++/98899] [10 Regression] ICE in tsubst_copy, at cp/pt.c:16198 since r10-1280-g78f7607db4c53f8c

[mpolacek at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=98899

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

           What    |Removed                     |Added
----------------------------------------------------------------------------
            Summary|[10/11 Regression] ICE in   |[10 Regression] ICE in
                   |tsubst_copy, at             |tsubst_copy, at
                   |cp/pt.c:16198 since         |cp/pt.c:16198 since
                   |r10-1280-g78f7607db4c53f8c  |r10-1280-g78f7607db4c53f8c

--- Comment #7 from Marek Polacek <mpolacek at gcc dot gnu.org> ---
Fixed on trunk so far.

[Bug c++/98899] [10 Regression] ICE in tsubst_copy, at cp/pt.c:16198 since r10-1280-g78f7607db4c53f8c

[rguenth at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=98899

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

           What    |Removed                     |Added
----------------------------------------------------------------------------
   Target Milestone|10.3                        |10.4

--- Comment #8 from Richard Biener <rguenth at gcc dot gnu.org> ---
GCC 10.3 is being released, retargeting bugs to GCC 10.4.

[Bug c++/98899] [10 Regression] ICE in tsubst_copy, at cp/pt.c:16198 since r10-1280-g78f7607db4c53f8c

[mpolacek at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=98899

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

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

--- Comment #9 from Marek Polacek <mpolacek at gcc dot gnu.org> ---
Not backporting to GCC 10.4 since it depends on another patch.