[Bug c++/72759] New: ICE on invalid C++ code on x86_64-linux-gnu (Segmentation fault, tree_class_check, ocp_convert)

[chengniansun at gmail dot com]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=72759

            Bug ID: 72759
           Summary: ICE on invalid C++ code on x86_64-linux-gnu
                    (Segmentation fault, tree_class_check, ocp_convert)
           Product: gcc
           Version: 7.0
            Status: UNCONFIRMED
          Severity: normal
          Priority: P3
         Component: c++
          Assignee: unassigned at gcc dot gnu.org
          Reporter: chengniansun at gmail dot com
  Target Milestone: ---

$ g++-trunk  -v
Using built-in specs.
COLLECT_GCC=g++-trunk
COLLECT_LTO_WRAPPER=/usr/local/gcc-trunk/libexec/gcc/x86_64-pc-linux-gnu/7.0.0/lto-wrapper
Target: x86_64-pc-linux-gnu
Configured with: ../gcc-source-trunk/configure --enable-languages=c,c++,lto
--prefix=/usr/local/gcc-trunk --disable-bootstrap
Thread model: posix
gcc version 7.0.0 20160730 (experimental) [trunk revision 238903] (GCC) 
$ g++-trunk small.C -std=c++14
small.C: In static member function ‘static void Specializer::A<<anonymous>
>::InnerMemberFn()’:
small.C:14:39: error: ‘SpecMbrFnPtr’ was not declared in this scope
   Spec ErrorSite = Spec::SpecMbrFnPtr<SpecMbrFnPtr>;
                                       ^~~~~~~~~~~~
small.C: In instantiation of ‘static void Specializer::A<<anonymous>
>::InnerMemberFn() [with unsigned int <anonymous> = 0u]’:
small.C:5:26:   required from here
small.C:14:8: internal compiler error: Segmentation fault
   Spec ErrorSite = Spec::SpecMbrFnPtr<SpecMbrFnPtr>;
        ^~~~~~~~~
0xdb298f crash_signal
        ../../gcc-source-trunk/gcc/toplev.c:335
0x7f5a9d tree_class_check(tree_node*, tree_code_class, char const*, int, char
const*)
        ../../gcc-source-trunk/gcc/tree.h:3145
0x7f5a9d ocp_convert(tree_node*, tree_node*, int, int, int)
        ../../gcc-source-trunk/gcc/cp/cvt.c:859
0x8049aa expand_default_init
        ../../gcc-source-trunk/gcc/cp/init.c:1685
0x8049aa expand_aggr_init_1
        ../../gcc-source-trunk/gcc/cp/init.c:1863
0x8051e4 build_aggr_init(tree_node*, tree_node*, int, int)
        ../../gcc-source-trunk/gcc/cp/init.c:1602
0x69ba94 build_aggr_init_full_exprs
        ../../gcc-source-trunk/gcc/cp/decl.c:6004
0x69ba94 check_initializer
        ../../gcc-source-trunk/gcc/cp/decl.c:6151
0x6bbb2e cp_finish_decl(tree_node*, tree_node*, bool, tree_node*, int)
        ../../gcc-source-trunk/gcc/cp/decl.c:6856
0x6f0171 tsubst_expr(tree_node*, tree_node*, int, tree_node*, bool)
        ../../gcc-source-trunk/gcc/cp/pt.c:15327
0x6ec644 tsubst_expr(tree_node*, tree_node*, int, tree_node*, bool)
        ../../gcc-source-trunk/gcc/cp/pt.c:15216
0x6ecb22 tsubst_expr(tree_node*, tree_node*, int, tree_node*, bool)
        ../../gcc-source-trunk/gcc/cp/pt.c:15401
0x6ea420 instantiate_decl(tree_node*, int, bool)
        ../../gcc-source-trunk/gcc/cp/pt.c:22133
0x732729 instantiate_pending_templates(int)
        ../../gcc-source-trunk/gcc/cp/pt.c:22252
0x778111 c_parse_final_cleanups()
        ../../gcc-source-trunk/gcc/cp/decl2.c:4601
Please submit a full bug report,
with preprocessed source if appropriate.
Please include the complete backtrace with any bug report.
See <http://gcc.gnu.org/bugs.html> for instructions.
$ 
$ cat small.C
template <typename> struct SpecPerType;
class Specializer {
  public:  template <bool> static void MbrFnTempl();
  template <unsigned> struct A { static void InnerMemberFn(); };
  void Trigger() { A<0>::InnerMemberFn; }
};
template <> struct SpecPerType<Specializer> {
  using FnType = void *;
  template <bool P>
  static constexpr FnType SpecMbrFnPtr = Specializer::MbrFnTempl<P>;
};
template <unsigned X> void Specializer::A<X>::InnerMemberFn() {
  using Spec = SpecPerType<Specializer>;
  Spec ErrorSite = Spec::SpecMbrFnPtr<SpecMbrFnPtr>;
}
$