https://gcc.gnu.org/bugzilla/show_bug.cgi?id=82782
Bug ID: 82782
Summary: ICE: nested template alias and specialized template
with auto template parameter
Product: gcc
Version: 8.0
Status: UNCONFIRMED
Severity: normal
Priority: P3
Component: c++
Assignee: unassigned at gcc dot gnu.org
Reporter: rbock at eudoxos dot de
Target Milestone: ---
Follow up to bug 82085:
This valid code now creates an internal compiler error:
// -----------------------------------------
template <const auto& Value>
struct make_char_sequence;
template <int N, const char (&StringLiteral)[N]>
struct make_char_sequence<StringLiteral>
{
using type = int;
};
template <const auto& StringLiteral>
using make_char_sequence_t = typename make_char_sequence<StringLiteral>::type;
inline constexpr char sample[] = "Sample";
using X = make_char_sequence_t<sample>;
// -----------------------------------------
g++ (GCC) 8.0.0 20171030 (experimental)
test.cpp: In substitution of ‘template<const auto& StringLiteral> using
make_char_sequence_t = typename make_char_sequence::type [with const auto&
StringLiteral = sample]’:
test.cpp:15:38: required from here
test.cpp:11:78: internal compiler error: unexpected expression ‘N’ of kind
template_parm_index
using make_char_sequence_t = typename make_char_sequence<StringLiteral>::type;
^
0x6bd33a cxx_eval_constant_expression
../../gcc-trunk/gcc/cp/constexpr.c:4638
0x6c197d cxx_eval_outermost_constant_expr
../../gcc-trunk/gcc/cp/constexpr.c:4697
0x6c4c46 maybe_constant_value(tree_node*, tree_node*)
../../gcc-trunk/gcc/cp/constexpr.c:4912
0x7198b4 compute_array_index_type(tree_node*, tree_node*, int)
../../gcc-trunk/gcc/cp/decl.c:9349
0x833768 tsubst(tree_node*, tree_node*, int, tree_node*)
../../gcc-trunk/gcc/cp/pt.c:13680
0x833538 tsubst(tree_node*, tree_node*, int, tree_node*)
../../gcc-trunk/gcc/cp/pt.c:14137
0x83312b tsubst(tree_node*, tree_node*, int, tree_node*)
../../gcc-trunk/gcc/cp/pt.c:13626
0x82e7f5 unify
../../gcc-trunk/gcc/cp/pt.c:20908
0x82f40f unify
../../gcc-trunk/gcc/cp/pt.c:21328
0x82f1e7 unify
../../gcc-trunk/gcc/cp/pt.c:21100
0x830232 get_partial_spec_bindings
../../gcc-trunk/gcc/cp/pt.c:21906
0x830ab1 most_specialized_partial_spec
../../gcc-trunk/gcc/cp/pt.c:22178
0x858107 instantiate_class_template_1
../../gcc-trunk/gcc/cp/pt.c:10341
0x858107 instantiate_class_template(tree_node*)
../../gcc-trunk/gcc/cp/pt.c:10909
0x8b12a2 complete_type(tree_node*)
../../gcc-trunk/gcc/cp/typeck.c:136
0x83403f tsubst(tree_node*, tree_node*, int, tree_node*)
../../gcc-trunk/gcc/cp/pt.c:14208
0x83dec6 tsubst_decl
../../gcc-trunk/gcc/cp/pt.c:13043
0x833e17 tsubst(tree_node*, tree_node*, int, tree_node*)
../../gcc-trunk/gcc/cp/pt.c:13553
0x83130d instantiate_template_1
../../gcc-trunk/gcc/cp/pt.c:18502
0x83130d instantiate_template(tree_node*, tree_node*, int)
../../gcc-trunk/gcc/cp/pt.c:18558
Minimized example, based on this code:
you can observe the code here:
https://github.com/rbock/sqlpp17/tree/1c424f9c1e4d9d9fa7e1c0cb48d27aec190f0da7
Compile with something something like:
export SOURCE_ROOT=$HOME/projects/sqlpp17
/usr/local/gcc-trunk/bin/g++ -I$SOURCE_ROOT/include -I$SOURCE_ROOT/tests
-std=c++1z -Wall -Wpedantic $SOURCE_ROOT/tests/serialize/join.cpp
