https://gcc.gnu.org/bugzilla/show_bug.cgi?id=67147
Bug ID: 67147 Summary: [concepts] ICE on checking concept with default template arguments Product: gcc Version: c++-concepts Status: UNCONFIRMED Severity: normal Priority: P3 Component: c++ Assignee: unassigned at gcc dot gnu.org Reporter: eric.niebler at gmail dot com Target Milestone: --- template <class F, class I1, class I2 = I1> concept bool IndirectCallableRelation() { return true; } template <class, class, class = void> constexpr bool indirect_relation() { return false; } IndirectCallableRelation{F, I1} constexpr bool indirect_relation() { return true; } IndirectCallableRelation{F, I1, I2} constexpr bool indirect_relation() { return true; } leads to: test.cpp:9:31: internal compiler error: in tsubst, at cp/pt.c:12607 IndirectCallableRelation{F, I1} ^ test.cpp:9:31: internal compiler error: Aborted g++: internal compiler error: Aborted (program cc1plus) Please submit a full bug report, with preprocessed source if appropriate. See <http://gcc.gnu.org/bugs.html> for instructions.