https://gcc.gnu.org/bugzilla/show_bug.cgi?id=67654
Bug ID: 67654 Summary: [concepts] ICE when using concepts in constexpr function Product: gcc Version: 6.0 Status: UNCONFIRMED Severity: normal Priority: P3 Component: c++ Assignee: unassigned at gcc dot gnu.org Reporter: ryan.burn at gmail dot com Target Milestone: --- Created attachment 36353 --> https://gcc.gnu.org/bugzilla/attachment.cgi?id=36353&action=edit reproduces problem My version of gcc: g++ (GCC) 6.0.0 20150915 (experimental) Copyright (C) 2015 Free Software Foundation, Inc. This is free software; see the source for copying conditions. There is NO warranty; not even for MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. The attached code causes this internal compiler error: main.cpp: In instantiation of ‘struct A<int, double>’: main.cpp:24:18: required from here main.cpp:20:33: error: no matching function for call to ‘and_c()’ A() requires and_c<C<Tx>()...>() = default; ^ main.cpp:10:42: note: candidate: template<bool ...Values> constexpr bool and_c() template <bool... Values> constexpr bool and_c() { ^ main.cpp:10:42: note: template argument deduction/substitution failed: main.cpp:20:33: internal compiler error: unexpected expression ‘C<int>’ of kind template_id_expr A() requires and_c<C<Tx>()...>() = default; ^ 0x816bc0 cxx_eval_constant_expression ../../gcc/gcc/cp/constexpr.c:3685 0x812e25 cxx_eval_call_expression ../../gcc/gcc/cp/constexpr.c:1186 0x81575f cxx_eval_constant_expression ../../gcc/gcc/cp/constexpr.c:3205 0x81a53b cxx_eval_outermost_constant_expr ../../gcc/gcc/cp/constexpr.c:3739 0x6846c6 convert_nontype_argument ../../gcc/gcc/cp/pt.c:6314 0x6846c6 convert_template_argument ../../gcc/gcc/cp/pt.c:7190 0x65a514 coerce_template_parameter_pack ../../gcc/gcc/cp/pt.c:7336 0x65a514 coerce_template_parms ../../gcc/gcc/cp/pt.c:7559 0x691bb3 fn_type_unification(tree_node*, tree_node*, tree_node*, tree_node* const*, unsigned int, tree_node*, unification_kind_t, int, bool, bool) ../../gcc/gcc/cp/pt.c:16871 0x5fa73b print_z_candidate ../../gcc/gcc/cp/call.c:3424 0x5fc33e print_z_candidates ../../gcc/gcc/cp/call.c:3494 0x605c17 build_new_function_call(tree_node*, vec<tree_node*, va_gc, vl_embed>**, bool, int) ../../gcc/gcc/cp/call.c:4104 0x78ff5e finish_call_expr(tree_node*, vec<tree_node*, va_gc, vl_embed>**, bool, bool, int) ../../gcc/gcc/cp/semantics.c:2391 0x68131f tsubst_copy_and_build(tree_node*, tree_node*, int, tree_node*, bool, bool) ../../gcc/gcc/cp/pt.c:15872 0x66aad1 tsubst_expr(tree_node*, tree_node*, int, tree_node*, bool) ../../gcc/gcc/cp/pt.c:15044 0x822ed6 tsubst_predicate_constraint(tree_node*, tree_node*, int, tree_node*) ../../gcc/gcc/cp/constraint.cc:1416 0x824fbf tsubst_constraint_info(tree_node*, tree_node*, int, tree_node*) ../../gcc/gcc/cp/constraint.cc:1638 0x6739d0 tsubst_decl ../../gcc/gcc/cp/pt.c:11501 0x6624c6 tsubst(tree_node*, tree_node*, int, tree_node*) ../../gcc/gcc/cp/pt.c:12426 0x697a26 instantiate_class_template_1 ../../gcc/gcc/cp/pt.c:9919 Please submit a full bug report, with preprocessed source if appropriate. Please include the complete backtrace with any bug report. See <http://gcc.gnu.org/bugs.html> for instructions.