https://gcc.gnu.org/bugzilla/show_bug.cgi?id=85200
Bug ID: 85200 Summary: [8 Regression] ICE in constexpr-if in lambda in template Product: gcc Version: 8.0.1 Status: UNCONFIRMED Severity: normal Priority: P3 Component: c++ Assignee: unassigned at gcc dot gnu.org Reporter: benni.buch at gmail dot com Target Milestone: --- struct A{ constexpr operator int(){ return 0; } }; template < typename > void f(){ [](auto known){ if constexpr(constexpr int k = known); }(A{}); } int main(){ f<int>(); } $ g++ -std=c++17 main.cpp main.cpp: In instantiation of 'f() [with <template-parameter-1-1> = int]::<lambda(auto:1)> [with auto:1 = A]': main.cpp:9:6: required from 'void f() [with <template-parameter-1-1> = int]' main.cpp:13:12: required from here main.cpp:8:36: internal compiler error: in tsubst_copy, at cp/pt.c:15001 if constexpr(constexpr int k = known); ^ 0x611c81 tsubst_copy ../../gcc/gcc/cp/pt.c:15001 0x930440 tsubst_copy_and_build(tree_node*, tree_node*, int, tree_node*, bool, bool) ../../gcc/gcc/cp/pt.c:18504 0x93f6bf tsubst_copy_and_build(tree_node*, tree_node*, int, tree_node*, bool, bool) ../../gcc/gcc/cp/pt.c:17345 0x93f6bf tsubst_expr(tree_node*, tree_node*, int, tree_node*, bool) ../../gcc/gcc/cp/pt.c:17077 0x9423c2 tsubst_expr(tree_node*, tree_node*, int, tree_node*, bool) ../../gcc/gcc/cp/pt.c:14946 0x9423c2 tsubst_init ../../gcc/gcc/cp/pt.c:14950 0x940ec8 tsubst_expr(tree_node*, tree_node*, int, tree_node*, bool) ../../gcc/gcc/cp/pt.c:16391 0x93ed68 tsubst_expr(tree_node*, tree_node*, int, tree_node*, bool) ../../gcc/gcc/cp/pt.c:17059 0x93e5a7 tsubst_expr(tree_node*, tree_node*, int, tree_node*, bool) ../../gcc/gcc/cp/pt.c:16508 0x93c81f tsubst_expr(tree_node*, tree_node*, int, tree_node*, bool) ../../gcc/gcc/cp/pt.c:16561 0x93c81f tsubst_expr(tree_node*, tree_node*, int, tree_node*, bool) ../../gcc/gcc/cp/pt.c:16561 0x93c81f tsubst_expr(tree_node*, tree_node*, int, tree_node*, bool) ../../gcc/gcc/cp/pt.c:16561 0x93b9b8 tsubst_expr(tree_node*, tree_node*, int, tree_node*, bool) ../../gcc/gcc/cp/pt.c:16249 0x93b9b8 instantiate_decl(tree_node*, bool, bool) ../../gcc/gcc/cp/pt.c:23659 0x882f9b maybe_instantiate_decl ../../gcc/gcc/cp/decl2.c:5190 0x884fd7 mark_used(tree_node*, int) ../../gcc/gcc/cp/decl2.c:5291 0x7eee9a build_over_call ../../gcc/gcc/cp/call.c:8246 0x7fd2ca build_op_call_1 ../../gcc/gcc/cp/call.c:4563 0x7fd2ca build_op_call(tree_node*, vec<tree_node*, va_gc, vl_embed>**, int) ../../gcc/gcc/cp/call.c:4592 0x97b13b finish_call_expr(tree_node*, vec<tree_node*, va_gc, vl_embed>**, bool, bool, int) ../../gcc/gcc/cp/semantics.c:2551 Please submit a full bug report, with preprocessed source if appropriate. Please include the complete backtrace with any bug report. See <https://gcc.gnu.org/bugs/> for instructions. $ g++ --version g++ (GCC) 8.0.1 20180404 (experimental) Copyright (C) 2018 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. Known to work in GCC 7: $ g++-7 --version g++-7 (GCC) 7.3.1 20180226 Copyright (C) 2017 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.