[Bug c++/99423] New: [modules] ICE tree check: expected tree_vec, have ggc_freed in lookup_template_class_1, at cp/pt.c:9803

[Bug c++/99423] New: [modules] ICE tree check: expected tree_vec, have ggc_freed in lookup_template_class_1, at cp/pt.c:9803

[alexander.lelyakin at googlemail dot com]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=99423

            Bug ID: 99423
           Summary: [modules] ICE tree check: expected tree_vec, have
                    ggc_freed in lookup_template_class_1, at cp/pt.c:9803
           Product: gcc
           Version: 11.0
            Status: UNCONFIRMED
          Severity: normal
          Priority: P3
         Component: c++
          Assignee: unassigned at gcc dot gnu.org
          Reporter: alexander.lelyakin at googlemail dot com
  Target Milestone: ---

g++ -std=c++20 -fmodules-ts -x c++-system-header unordered_map
g++ -std=c++20 -fmodules-ts -x c++-system-header functional
----
In file included from /usr/local/include/c++/11.0.1/bits/stl_algo.h:60,
                 from /usr/local/include/c++/11.0.1/vector:62,
                 from /usr/local/include/c++/11.0.1/functional:62:
/usr/local/include/c++/11.0.1/bits/algorithmfwd.h:259:24: internal compiler
error: tree check: expected tree_vec, have ggc_freed in
lookup_template_class_1, at cp/pt.c:9803
  259 |     pair<_FIter, _FIter>
      |                        ^
0x875966 tree_check_failed(tree_node const*, char const*, int, char const*,
...)
        ../../gcc/gcc/tree.c:9814
0x71d27b tree_check(tree_node*, char const*, int, char const*, tree_code)
        ../../gcc/gcc/tree.h:3353
0x71d27b lookup_template_class_1
        ../../gcc/gcc/cp/pt.c:9803
0xb21d1c lookup_template_class(tree_node*, tree_node*, tree_node*, tree_node*,
int, int)
        ../../gcc/gcc/cp/pt.c:10237
0xb49afb finish_template_type(tree_node*, tree_node*, int)
        ../../gcc/gcc/cp/semantics.c:3498
0xabbd21 cp_parser_template_id
        ../../gcc/gcc/cp/parser.c:17444
0xabbf0b cp_parser_class_name
        ../../gcc/gcc/cp/parser.c:24671
0xab349a cp_parser_qualifying_entity
        ../../gcc/gcc/cp/parser.c:6994
0xab349a cp_parser_nested_name_specifier_opt
        ../../gcc/gcc/cp/parser.c:6676
0xaa8db9 cp_parser_constructor_declarator_p
        ../../gcc/gcc/cp/parser.c:29643
0xaa8db9 cp_parser_decl_specifier_seq
        ../../gcc/gcc/cp/parser.c:15026
0xad3576 cp_parser_single_declaration
        ../../gcc/gcc/cp/parser.c:30402
0xad38f6 cp_parser_template_declaration_after_parameters
        ../../gcc/gcc/cp/parser.c:30065
0xad40a0 cp_parser_explicit_template_declaration
        ../../gcc/gcc/cp/parser.c:30331
0xad67c9 cp_parser_declaration
        ../../gcc/gcc/cp/parser.c:14047
0xad5d99 cp_parser_toplevel_declaration
        ../../gcc/gcc/cp/parser.c:14145
0xad5d99 cp_parser_declaration_seq_opt
        ../../gcc/gcc/cp/parser.c:13933
0xad6232 cp_parser_namespace_body
        ../../gcc/gcc/cp/parser.c:20433
0xad6232 cp_parser_namespace_definition
        ../../gcc/gcc/cp/parser.c:20411
0xad6988 cp_parser_declaration
        ../../gcc/gcc/cp/parser.c:14096
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.
----
g++ (GCC) 11.0.1 20210305 (experimental)
Copyright (C) 2021 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.

----

[Bug c++/99423] [modules] ICE tree check: expected tree_vec, have ggc_freed in lookup_template_class_1, at cp/pt.c:9803

[nathan at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=99423

Nathan Sidwell <nathan at gcc dot gnu.org> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
   Last reconfirmed|                            |2021-03-09
     Ever confirmed|0                           |1
             Status|UNCONFIRMED                 |ASSIGNED

[Bug c++/99423] [modules] ICE tree check: expected tree_vec, have ggc_freed in lookup_template_class_1, at cp/pt.c:9803

[nathan at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=99423

--- Comment #1 from Nathan Sidwell <nathan at gcc dot gnu.org> ---
// bug_a.ii
template<typename _T1>
struct pair
{
  pair() { }
};

inline pair<bool> blob ()
{
  return {};
}

// bug_b.ii
import  "bug_a.ii";

pair<bool> boom();

./cc1plus -fmodule-header=system -std=c++20 bug_a.ii -fpreprocessed -quiet &&
./cc1plus -fmodule-header=system -std=c++20 bug_b.ii -fpreprocessed -quiet
--param ggc-min-expand=0 --param ggc-min-heapsize=0
bug_b.ii:4:10: internal compiler error: tree check: expected tree_vec, have
ggc_freed in lookup_template_class_1, at cp/pt.c:9803
    4 | pair<bool> boom();
      |          ^
0x1acdc4b tree_check_failed(tree_node const*, char const*, int, char const*,
...)
        ../../../src/gcc/tree.c:9814
0xad685c tree_check(tree_node*, char const*, int, char const*, tree_code)
        ../../../src/gcc/tree.h:3353
0xdc6b60 lookup_template_class_1
        ../../../src/gcc/cp/pt.c:9803

[Bug c++/99423] [modules] ICE tree check: expected tree_vec, have ggc_freed in lookup_template_class_1, at cp/pt.c:9803

[cvs-commit at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=99423

--- Comment #2 from CVS Commits <cvs-commit at gcc dot gnu.org> ---
The master branch has been updated by Nathan Sidwell <nathan@gcc.gnu.org>:

https://gcc.gnu.org/g:1f428775acc391c8ce4fcf79b243043f3333cc99

commit r11-7610-g1f428775acc391c8ce4fcf79b243043f3333cc99
Author: Nathan Sidwell <nathan@acm.org>
Date:   Wed Mar 10 12:07:24 2021 -0800

    c++: ICE do to GC leakage [PR 99423]

    My reworking of pending-entity loading introduced a GC problem.  The
    post-load processing needs to inhibit GCs (that would otherwise occur
    in clone_decl).  That wasn't happening on one code path, leading to
    dangling pointers in the active call frames.

            PR c++/99423
            gcc/cp/
            * module.cc (post_load_processing): Assert not gcable.
            (laxy_load_pendings): Extend no-gc region around
            post_load_processing.
            gcc/testsuite/
            * g++.dg/modules/pr99423_a.H: New.
            * g++.dg/modules/pr99423_b.H: New.

[Bug c++/99423] [modules] ICE tree check: expected tree_vec, have ggc_freed in lookup_template_class_1, at cp/pt.c:9803

[nathan at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=99423

Nathan Sidwell <nathan at gcc dot gnu.org> changed:

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

--- Comment #3 from Nathan Sidwell <nathan at gcc dot gnu.org> ---
 1f428775acc 2021-03-10 | c++: ICE do to GC leakage [PR 99423]