https://gcc.gnu.org/bugzilla/show_bug.cgi?id=83947
Bug ID: 83947 Summary: ICE on invalid C++ code with auto: in tsubst_decl, at cp/pt.c:13046 Product: gcc Version: unknown Status: UNCONFIRMED Severity: normal Priority: P3 Component: c++ Assignee: unassigned at gcc dot gnu.org Reporter: su at cs dot ucdavis.edu Target Milestone: --- This appears to be a recent regression. $ g++tk -v Using built-in specs. COLLECT_GCC=g++tk COLLECT_LTO_WRAPPER=/home/su/software/tmp/gcc/gcc-trunk/libexec/gcc/x86_64-pc-linux-gnu/8.0.1/lto-wrapper Target: x86_64-pc-linux-gnu Configured with: ../gcc-source-trunk/configure --enable-languages=c,c++,lto --prefix=/home/su/software/tmp/gcc/gcc-trunk --disable-bootstrap Thread model: posix gcc version 8.0.1 20180117 (experimental) [trunk revision 256779] (GCC) $ $ g++-7.2.0 -c tmp.cpp tmp.cpp: In instantiation of ‘auto g<0>’: tmp.cpp:3:10: required from here tmp.cpp:2:23: error: use of ‘auto f()’ before deduction of ‘auto’ template < int > auto g (f); ^ $ $ g++tk -c tmp.cpp tmp.cpp:2:23: internal compiler error: in tsubst_decl, at cp/pt.c:13046 template < int > auto g (f); ^ 0x86faa0 tsubst_decl ../../gcc-source-trunk/gcc/cp/pt.c:13046 0x876996 tsubst(tree_node*, tree_node*, int, tree_node*) ../../gcc-source-trunk/gcc/cp/pt.c:13562 0x8749b5 instantiate_template_1 ../../gcc-source-trunk/gcc/cp/pt.c:18569 0x8749b5 instantiate_template(tree_node*, tree_node*, int) ../../gcc-source-trunk/gcc/cp/pt.c:18625 0x8c81b6 finish_id_expression(tree_node*, tree_node*, tree_node*, cp_id_kind*, bool, bool, bool*, bool, bool, bool, bool, char const**, unsigned int) ../../gcc-source-trunk/gcc/cp/semantics.c:3679 0x80a1a2 cp_parser_primary_expression ../../gcc-source-trunk/gcc/cp/parser.c:5615 0x817443 cp_parser_postfix_expression ../../gcc-source-trunk/gcc/cp/parser.c:7029 0x82087c cp_parser_unary_expression ../../gcc-source-trunk/gcc/cp/parser.c:8281 0x7fa8a9 cp_parser_cast_expression ../../gcc-source-trunk/gcc/cp/parser.c:9049 0x7fafa5 cp_parser_binary_expression ../../gcc-source-trunk/gcc/cp/parser.c:9151 0x7fb890 cp_parser_assignment_expression ../../gcc-source-trunk/gcc/cp/parser.c:9439 0x7fc883 cp_parser_constant_expression ../../gcc-source-trunk/gcc/cp/parser.c:9721 0x7fcd67 cp_parser_initializer_clause ../../gcc-source-trunk/gcc/cp/parser.c:21842 0x7ffcfb cp_parser_initializer ../../gcc-source-trunk/gcc/cp/parser.c:21780 0x8227a4 cp_parser_init_declarator ../../gcc-source-trunk/gcc/cp/parser.c:19601 0x824248 cp_parser_simple_declaration ../../gcc-source-trunk/gcc/cp/parser.c:12997 0x8250cf cp_parser_block_declaration ../../gcc-source-trunk/gcc/cp/parser.c:12815 0x830770 cp_parser_declaration ../../gcc-source-trunk/gcc/cp/parser.c:12712 0x82f3b4 cp_parser_declaration_seq_opt ../../gcc-source-trunk/gcc/cp/parser.c:12588 0x82f6f7 cp_parser_translation_unit ../../gcc-source-trunk/gcc/cp/parser.c:4559 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. $ ------------------------------- auto f (); template < int > auto g (f); auto h = g < 0 > ();