https://gcc.gnu.org/bugzilla/show_bug.cgi?id=77790
Bug ID: 77790 Summary: ICE on valid C++14 code when compiling with "-std=c++11": in push_access_scope, at cp/pt.c:227 Product: gcc Version: 7.0 Status: UNCONFIRMED Severity: normal Priority: P3 Component: c++ Assignee: unassigned at gcc dot gnu.org Reporter: su at cs dot ucdavis.edu Target Milestone: --- It appears to be a regression from 4.8.x, and affects 4.9.x and later. $ g++-trunk -v Using built-in specs. COLLECT_GCC=g++-trunk COLLECT_LTO_WRAPPER=/usr/local/gcc-trunk/libexec/gcc/x86_64-pc-linux-gnu/7.0.0/lto-wrapper Target: x86_64-pc-linux-gnu Configured with: ../gcc-source-trunk/configure --enable-languages=c,c++,lto --prefix=/usr/local/gcc-trunk --disable-bootstrap Thread model: posix gcc version 7.0.0 20160928 (experimental) [trunk revision 240585] (GCC) $ $ g++-trunk -c -std=c++14 small.cpp $ $ g++-trunk -c -std=c++11 small.cpp small.cpp:3:42: error: ‘f’ function uses ‘auto’ type specifier without trailing return type template < typename T > static auto f () { return 0; } ^ small.cpp:3:42: note: deduced return type only available with -std=c++14 or -std=gnu++14 small.cpp:7:26: internal compiler error: in push_access_scope, at cp/pt.c:227 auto a = A < int > {}.g (); ^ 0x6c2c37 push_access_scope ../../gcc-source-trunk/gcc/cp/pt.c:226 0x71e343 fn_type_unification(tree_node*, tree_node*, tree_node*, tree_node* const*, unsigned int, tree_node*, unification_kind_t, int, bool, bool) ../../gcc-source-trunk/gcc/cp/pt.c:18004 0x67bfbb add_template_candidate_real ../../gcc-source-trunk/gcc/cp/call.c:3120 0x67ccec add_template_candidate ../../gcc-source-trunk/gcc/cp/call.c:3198 0x67ccec add_candidates ../../gcc-source-trunk/gcc/cp/call.c:5400 0x67d759 build_new_method_call_1 ../../gcc-source-trunk/gcc/cp/call.c:8515 0x67d759 build_new_method_call(tree_node*, tree_node*, vec<tree_node*, va_gc, vl_embed>**, tree_node*, int, tree_node**, int) ../../gcc-source-trunk/gcc/cp/call.c:8714 0x79e483 cp_parser_postfix_expression ../../gcc-source-trunk/gcc/cp/parser.c:6908 0x79c01c cp_parser_unary_expression ../../gcc-source-trunk/gcc/cp/parser.c:8019 0x7a5e57 cp_parser_cast_expression ../../gcc-source-trunk/gcc/cp/parser.c:8696 0x7a6455 cp_parser_binary_expression ../../gcc-source-trunk/gcc/cp/parser.c:8798 0x7a6d40 cp_parser_assignment_expression ../../gcc-source-trunk/gcc/cp/parser.c:9086 0x7a717a cp_parser_constant_expression ../../gcc-source-trunk/gcc/cp/parser.c:9354 0x7a7904 cp_parser_initializer_clause ../../gcc-source-trunk/gcc/cp/parser.c:21048 0x7a929b cp_parser_initializer ../../gcc-source-trunk/gcc/cp/parser.c:20986 0x7bb3fc cp_parser_init_declarator ../../gcc-source-trunk/gcc/cp/parser.c:18851 0x7bbb39 cp_parser_simple_declaration ../../gcc-source-trunk/gcc/cp/parser.c:12567 0x7bbe71 cp_parser_block_declaration ../../gcc-source-trunk/gcc/cp/parser.c:12435 0x7c3dd0 cp_parser_declaration ../../gcc-source-trunk/gcc/cp/parser.c:12332 0x7c2914 cp_parser_declaration_seq_opt ../../gcc-source-trunk/gcc/cp/parser.c:12211 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. $ ------------------------------------------------------------------------- template < typename S > struct A { template < typename T > static auto f () { return 0; } template < class U = decltype (f < S > ()) > int g () { return 0; } }; auto a = A < int > {}.g ();