https://gcc.gnu.org/bugzilla/show_bug.cgi?id=94628
--- Comment #8 from Martin Liška <marxin at gcc dot gnu.org> ---
(In reply to Nicholas Krause from comment #7)
> After adding this it seems to work for me, Patrick:
> case TYPE_ARGUMENT_PACK:
> if (value_dependent_expression_p(TREE_TYPE(*tp)))
> return *tp;
> if (TEMPLATE_TYPE_PARAMETER_PACK(*tp))
> return *tp;
> return NULL_TREE;
>
> and gives me:
> test.c: In function ‘std::common_type_t<decltype
> (forward<F>(f)(std::integral_constant<int, i>(),
> (forward<decltype(args)>)(args)...)), decltype
> (forward<F>(f)(int_constant<Is>(), (forward<decltype(args)>)(args)...))...>
> select(int, F&&, Args&& ...)’:
> test.c:14:12: warning: ‘if constexpr’ only available with ‘-std=c++17’ or
> ‘-std=gnu++17’
> 14 | if constexpr(sizeof...(Is)>0)
> | ^~~~~~~~~
> test.c: In function ‘std::common_type_t<decltype
> (forward<F>(f)(std::integral_constant<int, i>(),
> (forward<decltype(select::args)>)(select::args)...)), decltype
> (forward<F>(f)(int_constant<Is>(),
> (forward<decltype(select::args)>)(select::args)...))...> select(int, F&&,
> Args&& ...) [with int I = 1; int ...Is = {}; F = t(int)::<lambda(auto:1)>;
> Args = {}]’:
> test.c:17:1: warning: control reaches end of non-void function
> [-Wreturn-type]
> 17 | }
> | ^
>
> with no segfault. I'm not sure if this is the correct part to add this test
> for TYPE_ARGUMENT_PACK or if we would prefer it to be lower in the stack.
The suggested change is wrong:
/home/marxin/Programming/gcc2/objdir/./gcc/xgcc -shared-libgcc
-B/home/marxin/Programming/gcc2/objdir/./gcc -nostdinc++
-L/home/marxin/Programming/gcc2/objdir/x86_64-pc-linux-gnu/libstdc++-v3/src
-L/home/marxin/Programming/gcc2/objdir/x86_64-pc-linux-gnu/libstdc++-v3/src/.libs
-L/home/marxin/Programming/gcc2/objdir/x86_64-pc-linux-gnu/libstdc++-v3/libsupc++/.libs
-B/usr/local/x86_64-pc-linux-gnu/bin/ -B/usr/local/x86_64-pc-linux-gnu/lib/
-isystem /usr/local/x86_64-pc-linux-gnu/include -isystem
/usr/local/x86_64-pc-linux-gnu/sys-include -x c++-header -nostdinc++ -g -O2
-D_GNU_SOURCE
-I/home/marxin/Programming/gcc2/objdir/x86_64-pc-linux-gnu/libstdc++-v3/include/x86_64-pc-linux-gnu
-I/home/marxin/Programming/gcc2/objdir/x86_64-pc-linux-gnu/libstdc++-v3/include
-I/home/marxin/Programming/gcc2/libstdc++-v3/libsupc++ -O2 -g -std=gnu++0x
/home/marxin/Programming/gcc2/libstdc++-v3/include/precompiled/stdc++.h \
-o x86_64-pc-linux-gnu/bits/stdc++.h.gch/O2ggnu++0x.gch
In file included from
/home/marxin/Programming/gcc2/objdir/x86_64-pc-linux-gnu/libstdc++-v3/include/cmath:42,
from
/home/marxin/Programming/gcc2/libstdc++-v3/include/precompiled/stdc++.h:41:
/home/marxin/Programming/gcc2/objdir/x86_64-pc-linux-gnu/libstdc++-v3/include/bits/cpp_type_traits.h:89:63:
internal compiler error: tree check: expected template_type_parm or
template_template_parm or bound_template_template_parm, have tree_list in
instantiation_dependent_r, at cp/pt.c:26926
89 | enum { __value = bool(_Sp::__value) || bool(_Tp::__value) };
| ^
0x8404c2 tree_check_failed(tree_node const*, char const*, int, char const*,
...)
../../gcc/tree.c:9727
0x69234b tree_check3(tree_node*, char const*, int, char const*, tree_code,
tree_code, tree_code)
../../gcc/tree.h:3327
0x69234b instantiation_dependent_r
../../gcc/cp/pt.c:26926
0x13749b3 walk_tree_1(tree_node**, tree_node* (*)(tree_node**, int*, void*),
void*, hash_set<tree_node*, false, default_hash_traits<tree_node*> >*,
tree_node* (*)(tree_node**, int*, tree_node* (*)(tree_node**, int*, void*),
void*, hash_set<tree_node*, false, default_hash_traits<tree_node*> >*))
../../gcc/tree.c:11996
0xb10a88 cp_walk_subtrees(tree_node**, int*, tree_node* (*)(tree_node**, int*,
void*), void*, hash_set<tree_node*, false, default_hash_traits<tree_node*> >*)
../../gcc/cp/tree.c:5061
0x1374a47 walk_tree_1(tree_node**, tree_node* (*)(tree_node**, int*, void*),
void*, hash_set<tree_node*, false, default_hash_traits<tree_node*> >*,
tree_node* (*)(tree_node**, int*, tree_node* (*)(tree_node**, int*, void*),
void*, hash_set<tree_node*, false, default_hash_traits<tree_node*> >*))
../../gcc/tree.c:12019
0x1377c85 walk_tree_without_duplicates_1(tree_node**, tree_node*
(*)(tree_node**, int*, void*), void*, tree_node* (*)(tree_node**, int*,
tree_node* (*)(tree_node**, int*, void*), void*, hash_set<tree_node*, false,
default_hash_traits<tree_node*> >*))
../../gcc/tree.c:12352
0xa97c87 instantiation_dependent_uneval_expression_p(tree_node*)
../../gcc/cp/pt.c:27033
0xa9e278 instantiation_dependent_expression_p(tree_node*)
../../gcc/cp/pt.c:27043
0x973ba7 is_nondependent_constant_expression(tree_node*)
../../gcc/cp/constexpr.c:8300
0x973fca fold_non_dependent_expr_template
../../gcc/cp/constexpr.c:6970
0xa98147 build_non_dependent_expr(tree_node*)
../../gcc/cp/pt.c:27531
0xb271ef build_x_binary_op(op_location_t const&, tree_code, tree_node*,
tree_code, tree_node*, tree_code, tree_node**, int)
../../gcc/cp/typeck.c:4245
0xa54e71 cp_parser_binary_expression
../../gcc/cp/parser.c:9719
0xa5671e cp_parser_assignment_expression
../../gcc/cp/parser.c:9859
0xa556cd cp_parser_constant_expression
../../gcc/cp/parser.c:10153
0xa62028 cp_parser_enumerator_definition
../../gcc/cp/parser.c:19479
0xa62028 cp_parser_enumerator_list
../../gcc/cp/parser.c:19419
0xa62028 cp_parser_enum_specifier
../../gcc/cp/parser.c:19350
0xa62028 cp_parser_type_specifier
../../gcc/cp/parser.c:17680
Can you please next time send patch suggestion that at least survive GCC build?
