https://gcc.gnu.org/bugzilla/show_bug.cgi?id=122958
Bug ID: 122958
Summary: [13/14/15/16 Regression] internal compiler error: tree
check: accessed elt 3 of 'tree_vec' with 2 elts in
tsubst, at cp/pt.cc:16806
Product: gcc
Version: 16.0
Status: UNCONFIRMED
Keywords: ice-on-invalid-code
Severity: normal
Priority: P3
Component: c++
Assignee: unassigned at gcc dot gnu.org
Reporter: redi at gcc dot gnu.org
Target Milestone: ---
template<typename A, typename B> struct Value { static constexpr bool value =
false; };
template<bool> struct Type { using type = void; };
template <class>
class Signal;
template <class RetT, class... Args>
class Signal<RetT(Args...)>;
template <
class RetT,
class... Args,
class RetTC = typename Type<Value<RetT, void>::value>::type>
class Signal<RetT(Args...)>
{
};
Signal<void()> priv_signal_modified_changed2;
Using GCC 4.7.2 correctly rejects this:
<source>:14:7: error: default template arguments may not be used in partial
specializations
<source>:14:7: error: template parameters not used in partial specialization:
<source>:14:7: error: 'RetTC'
<source>:18:16: error: aggregate 'Signal<void()> priv_signal_modified_changed2'
has incomplete type and cannot be defined
Compiler returned: 1
GCC 4.7.[34] compiled this successfully! (accepts-invalid)
GCC 4.8.0 and later gives an ICE.
With trunk it says:
pr122958.cc: In instantiation of 'class Signal<void()>':
required from here
pr122958.cc:18:16:
18 | Signal<void()> priv_signal_modified_changed2;
| ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~
pr122958.cc:15:1: internal compiler error: tree check: accessed elt 3 of
'tree_vec' with 2 elts in tsubst, at cp/pt.cc:16806
15 | {
| ^
0x2514f4d internal_error(char const*, ...)
/home/jwakely/src/gcc/gcc/gcc/diagnostic-global-context.cc:787
0x626dc8 tree_vec_elt_check_failed(int, int, char const*, int, char const*)
/home/jwakely/src/gcc/gcc/gcc/tree.cc:9390
0x794d5c tree_vec_elt_check(tree_node*, int, char const*, int, char const*)
/home/jwakely/src/gcc/gcc/gcc/tree.h:3999
0x9c3062 tsubst(tree_node*, tree_node*, int, tree_node*)
/home/jwakely/src/gcc/gcc/gcc/cp/pt.cc:16806
0x9c8e59 tsubst_template_args(tree_node*, tree_node*, int, tree_node*)
/home/jwakely/src/gcc/gcc/gcc/cp/pt.cc:14383
0x9c203d tsubst(tree_node*, tree_node*, int, tree_node*)
/home/jwakely/src/gcc/gcc/gcc/cp/pt.cc:17025
0x9b4803 tsubst_decl
/home/jwakely/src/gcc/gcc/gcc/cp/pt.cc:15888
0x9c1d82 tsubst(tree_node*, tree_node*, int, tree_node*)
/home/jwakely/src/gcc/gcc/gcc/cp/pt.cc:16608
0x9e39ef instantiate_class_template(tree_node*)
/home/jwakely/src/gcc/gcc/gcc/cp/pt.cc:12882
0xa40ce4 complete_type(tree_node*)
/home/jwakely/src/gcc/gcc/gcc/cp/typeck.cc:138
0x7e2878 start_decl_1(tree_node*, bool)
/home/jwakely/src/gcc/gcc/gcc/cp/decl.cc:6776
0x7e2878 start_decl_1(tree_node*, bool)
/home/jwakely/src/gcc/gcc/gcc/cp/decl.cc:6755
0x804551 start_decl(cp_declarator const*, cp_decl_specifier_seq*, int,
tree_node*, tree_node*, tree_node**)
/home/jwakely/src/gcc/gcc/gcc/cp/decl.cc:6742
0x9698ba cp_parser_init_declarator
/home/jwakely/src/gcc/gcc/gcc/cp/parser.cc:24895
0x96c72f cp_parser_simple_declaration
/home/jwakely/src/gcc/gcc/gcc/cp/parser.cc:17195
0x979878 cp_parser_declaration
/home/jwakely/src/gcc/gcc/gcc/cp/parser.cc:16815
0x97adab cp_parser_toplevel_declaration
/home/jwakely/src/gcc/gcc/gcc/cp/parser.cc:16836
0x97adab cp_parser_translation_unit
/home/jwakely/src/gcc/gcc/gcc/cp/parser.cc:5506
0x97adab c_parse_file()
/home/jwakely/src/gcc/gcc/gcc/cp/parser.cc:55266
0xaea641 c_common_parse_file()
/home/jwakely/src/gcc/gcc/gcc/c-family/c-opts.cc:1418
Please submit a full bug report, with preprocessed source (by using
-freport-bug).
Please include the complete backtrace with any bug report.
See <https://gcc.gnu.org/bugs/> for instructions.
