https://gcc.gnu.org/bugzilla/show_bug.cgi?id=85209
Bug ID: 85209 Summary: [8 Regression] ICE with lambda and structured binding Product: gcc Version: 8.0 Status: UNCONFIRMED Keywords: ice-on-invalid-code Severity: normal Priority: P3 Component: c++ Assignee: unassigned at gcc dot gnu.org Reporter: reichelt at gcc dot gnu.org Target Milestone: --- The following invalid code snippet (compiled with "-std=c++17") triggers an ICE on trunk: =========================== template<int> void foo() { auto [a] = []{}; }; void bar() { foo<0>(); } =========================== bug.cc: In instantiation of 'void foo() [with int <anonymous> = 0]': bug.cc:8:10: required from here bug.cc:3:8: internal compiler error: in tsubst_decomp_names, at cp/pt.c:16223 auto [a] = []{}; ^~~ 0x6456bb tsubst_decomp_names ../../gcc/gcc/cp/pt.c:16223 0x974695 tsubst_expr(tree_node*, tree_node*, int, tree_node*, bool) ../../gcc/gcc/cp/pt.c:16403 0x971764 tsubst_expr(tree_node*, tree_node*, int, tree_node*, bool) ../../gcc/gcc/cp/pt.c:16264 0x96f15f tsubst_expr(tree_node*, tree_node*, int, tree_node*, bool) ../../gcc/gcc/cp/pt.c:16561 0x96e2f8 tsubst_expr(tree_node*, tree_node*, int, tree_node*, bool) ../../gcc/gcc/cp/pt.c:16249 0x96e2f8 instantiate_decl(tree_node*, bool, bool) ../../gcc/gcc/cp/pt.c:23659 0x9932db instantiate_pending_templates(int) ../../gcc/gcc/cp/pt.c:23775 0x8b893b c_parse_final_cleanups() ../../gcc/gcc/cp/decl2.c:4724 Please submit a full bug report, [etc.] The regression was introduced between 2017-08-19 and 2017-09-02. Before, the code was correctly rejected: bug.cc: In instantiation of 'void foo() [with int <anonymous> = 0]': bug.cc:8:10: required from here bug.cc:3:8: error: cannot decompose lambda closure type 'foo() [with int <anonymous> = 0]::<lambda()>' auto [a] = []{}; ^~~