[Bug c++/88295] New: ICE on (invalid) C++11 code: tree check: expected class ‘expression’, have ‘exceptiona’ (argument_pack_select) in tree_operand_check, at tree.h:3652

[su at cs dot ucdavis.edu]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=88295

            Bug ID: 88295
           Summary: ICE on (invalid) C++11 code: tree check: expected
                    class ‘expression’, have ‘exceptiona’
                    (argument_pack_select) in tree_operand_check, at
                    tree.h:3652
           Product: gcc
           Version: unknown
            Status: UNCONFIRMED
          Severity: normal
          Priority: P3
         Component: c++
          Assignee: unassigned at gcc dot gnu.org
          Reporter: su at cs dot ucdavis.edu
  Target Milestone: ---

This appears to be a recent regression. 

The error message also contains a small, but obvious typo: `exceptiona' should
have been ‘exceptional’. 

$ g++tk -v
Using built-in specs.
COLLECT_GCC=g++tk
COLLECT_LTO_WRAPPER=/home/su/software/tmp/gcc/gcc-trunk/libexec/gcc/x86_64-pc-linux-gnu/9.0.0/lto-wrapper
Target: x86_64-pc-linux-gnu
Configured with: ../gcc-source-trunk/configure --enable-languages=c,c++,lto
--prefix=/home/su/software/tmp/gcc/gcc-trunk --disable-bootstrap
Thread model: posix
gcc version 9.0.0 20181201 (experimental) [trunk revision 266708] (GCC) 
$ 
$ g++tk -c tmp.cpp
tmp.cpp: In instantiation of ‘void f(T ...) [with T = {int}]’:
tmp.cpp:6:21:   required from here
tmp.cpp:3:8: internal compiler error: tree check: expected class ‘expression’,
have ‘exceptional’ (argument_pack_select) in tree_operand_check, at tree.h:3652
    3 |   f (t (t ...) ...);
      |      ~~^~~~~~~
0x605f6b tree_class_check_failed(tree_node const*, tree_code_class, char
const*, int, char const*)
        ../../gcc-source-trunk/gcc/tree.c:9810
0x829ff9 expr_check(tree_node*, char const*, int, char const*)
        ../../gcc-source-trunk/gcc/tree.h:3323
0x829ff9 tree_operand_check(tree_node*, int, char const*, int, char const*)
        ../../gcc-source-trunk/gcc/tree.h:3652
0x829ff9 argument_pack_element_is_expansion_p
        ../../gcc-source-trunk/gcc/cp/pt.c:11522
0x85ddfd tsubst_pack_expansion(tree_node*, tree_node*, int, tree_node*)
        ../../gcc-source-trunk/gcc/cp/pt.c:12147
0x8484de tsubst_copy_and_build(tree_node*, tree_node*, int, tree_node*, bool,
bool)
        ../../gcc-source-trunk/gcc/cp/pt.c:18648
0x850b27 tsubst_expr(tree_node*, tree_node*, int, tree_node*, bool)
        ../../gcc-source-trunk/gcc/cp/pt.c:17745
0x85e989 gen_elem_of_pack_expansion_instantiation
        ../../gcc-source-trunk/gcc/cp/pt.c:11687
0x85e989 tsubst_pack_expansion(tree_node*, tree_node*, int, tree_node*)
        ../../gcc-source-trunk/gcc/cp/pt.c:12301
0x8484de tsubst_copy_and_build(tree_node*, tree_node*, int, tree_node*, bool,
bool)
        ../../gcc-source-trunk/gcc/cp/pt.c:18648
0x850b27 tsubst_expr(tree_node*, tree_node*, int, tree_node*, bool)
        ../../gcc-source-trunk/gcc/cp/pt.c:17745
0x850369 tsubst_expr(tree_node*, tree_node*, int, tree_node*, bool)
        ../../gcc-source-trunk/gcc/cp/pt.c:16866
0x84e8da tsubst_expr(tree_node*, tree_node*, int, tree_node*, bool)
        ../../gcc-source-trunk/gcc/cp/pt.c:17152
0x84cda6 instantiate_decl(tree_node*, bool, bool)
        ../../gcc-source-trunk/gcc/cp/pt.c:24446
0x892ad0 instantiate_pending_templates(int)
        ../../gcc-source-trunk/gcc/cp/pt.c:24562
0x76ae22 c_parse_final_cleanups()
        ../../gcc-source-trunk/gcc/cp/decl2.c:4771
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.
$ 


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template < typename ... T > void f (T ... t)
{
  f (t (t ...) ...);
}

template void f (int);