https://gcc.gnu.org/bugzilla/show_bug.cgi?id=85263
Bug ID: 85263
Summary: [concepts] ICE with parameter pack matching
Product: gcc
Version: 8.0
Status: UNCONFIRMED
Keywords: error-recovery, ice-on-invalid-code
Severity: normal
Priority: P3
Component: c++
Assignee: unassigned at gcc dot gnu.org
Reporter: reichelt at gcc dot gnu.org
Blocks: 67491
Target Milestone: ---
The following invalid code snippet (compiled with "-fconcepts") triggers
an ICE since GCC 6.1.0:
=======================================================
template<typename..., int...> concept bool C = true;
C{A, B} void foo();
=======================================================
bug.cc:3:3: error: cannot match pack for introduced parameter
C{A, B} void foo();
^
bug.cc:3:7: internal compiler error: tree check: accessed elt 1 of tree_vec
with 0 elts in process_introduction_parm, at cp/constraint.cc:1325
C{A, B} void foo();
^
0x78f405 tree_vec_elt_check_failed(int, int, char const*, int, char const*)
../../gcc/gcc/tree.c:9520
0x5e94ec tree_vec_elt_check(tree_node*, int, char const*, int, char const*)
../../gcc/gcc/tree.h:3356
0x5e94ec process_introduction_parm
../../gcc/gcc/cp/constraint.cc:1325
0x5e94ec finish_template_introduction(tree_node*, tree_node*)
../../gcc/gcc/cp/constraint.cc:1408
0x944368 cp_parser_template_introduction
../../gcc/gcc/cp/parser.c:27066
0x944368 cp_parser_template_declaration_after_export
../../gcc/gcc/cp/parser.c:27170
0x949714 cp_parser_declaration
../../gcc/gcc/cp/parser.c:12767
0x949b31 cp_parser_declaration_seq_opt
../../gcc/gcc/cp/parser.c:12648
0x949e24 cp_parser_translation_unit
../../gcc/gcc/cp/parser.c:4563
0x949e24 c_parse_file()
../../gcc/gcc/cp/parser.c:39029
0xa49bb6 c_common_parse_file()
../../gcc/gcc/c-family/c-opts.c:1132
Please submit a full bug report, [etc.]
Referenced Bugs:
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=67491
[Bug 67491] [meta-bug] concepts issues
