https://gcc.gnu.org/bugzilla/show_bug.cgi?id=117102
Bug ID: 117102 Summary: internal compiler error: tree check: accessed elt 2 of 'tree_vec' with 1 elts in unify, at cp/pt.cc:24866 Product: gcc Version: unknown Status: UNCONFIRMED Severity: normal Priority: P3 Component: c++ Assignee: unassigned at gcc dot gnu.org Reporter: yihan4845 at gmail dot com Target Milestone: --- Compiler Explorer: https://godbolt.org/z/qx5TTdE3d The following program: ```cpp template<int a, auto F2> struct S; template<int a, class C2, auto C2::* F2> struct S<a, F2> {}; class Bar { void f(){} S<0, &Bar::f> c; }; ``` will trigger segmentation fault for gcc trunk. Stack dump: ``` 0x2854355 diagnostic_context::diagnostic_impl(rich_location*, diagnostic_metadata const*, diagnostic_option_id, char const*, __va_list_tag (*) [1], diagnostic_t) ???:0 0x2868135 internal_error(char const*, ...) ???:0 0x99bfd7 tree_vec_elt_check_failed(int, int, char const*, int, char const*) ???:0 0xb05396 tree_vec_elt_check(tree_node*, int, char const*, int, char const*) ???:0 0xcb7d71 do_auto_deduction(tree_node*, tree_node*, tree_node*, int, auto_deduction_context, tree_node*, int, tree_node*) ???:0 0xcbf5c5 most_specialized_partial_spec(tree_node*, int, bool) ???:0 0xcf8e35 instantiate_class_template(tree_node*) ???:0 0xb6e767 grokdeclarator(cp_declarator const*, cp_decl_specifier_seq*, decl_context, int, tree_node**) ???:0 0xb8e3c0 grokfield(cp_declarator const*, cp_decl_specifier_seq*, tree_node*, bool, tree_node*, tree_node*) ???:0 0xc98d9a c_parse_file() ???:0 0xdf0959 c_common_parse_file() ???:0 Please submit a full bug report, with preprocessed source (by using -freport-bug). Please include the complete backtrace with any bug report. See <https://gcc.gnu.org/bugs/> for instructions. Compiler returned: 1 ```