[Bug c++/96465] New: ICE in tsubst_function_decl, at cp/pt.c:13669

[haoxintu at gmail dot com]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=96465

            Bug ID: 96465
           Summary: ICE in tsubst_function_decl, at cp/pt.c:13669
           Product: gcc
           Version: 11.0
            Status: UNCONFIRMED
          Keywords: error-recovery, ice-on-invalid-code
          Severity: normal
          Priority: P3
         Component: c++
          Assignee: unassigned at gcc dot gnu.org
          Reporter: haoxintu at gmail dot com
  Target Milestone: ---

Hi, all.

This code, similar with bug 96464 code, makes GCC-7.1 onwards versions ICE or
"confused by earlier errors". It seems that GCC have some room to enhance its
error-recovery on this case.

Input
//small.cc
void foo(){
    auto var = [] (class b<auto>...) {};
}

Command:
g++ small.cc

Output:
small.cc: In function ‘void foo()’:
small.cc:2:26: error: ‘b’ is not a class template
    2 |     auto var = [] (class b<auto>...) {};
      |                          ^
small.cc:1:6: internal compiler error: in tsubst_function_decl, at
cp/pt.c:13669
    1 | void foo(){
      |      ^~~
0x66004a tsubst_function_decl
        ../../gcc/cp/pt.c:13669
0xa00832 tsubst_decl
        ../../gcc/cp/pt.c:14216
0xa0c74f lookup_template_class_1
        ../../gcc/cp/pt.c:9852
0xa0e813 lookup_template_class(tree_node*, tree_node*, tree_node*, tree_node*,
int, int)
        ../../gcc/cp/pt.c:10139
0xa0e813 tsubst_aggr_type
        ../../gcc/cp/pt.c:13395
0x9c94ef cp_parser_parameter_declaration
        ../../gcc/cp/parser.c:22961
0x9c9a82 cp_parser_parameter_declaration_list
        ../../gcc/cp/parser.c:22681
0x9c9e81 cp_parser_parameter_declaration_clause
        ../../gcc/cp/parser.c:22608
0x9ca993 cp_parser_lambda_declarator_opt
        ../../gcc/cp/parser.c:11134
0x9b0831 cp_parser_lambda_expression
        ../../gcc/cp/parser.c:10665
0x9b18b0 cp_parser_primary_expression
        ../../gcc/cp/parser.c:5475
0x9bbdd5 cp_parser_postfix_expression
        ../../gcc/cp/parser.c:7328
0x99daaa cp_parser_binary_expression
        ../../gcc/cp/parser.c:9641
0x99f83e cp_parser_assignment_expression
        ../../gcc/cp/parser.c:9946
0x99e3bd cp_parser_constant_expression
        ../../gcc/cp/parser.c:10240
0x99ebe1 cp_parser_initializer_clause
        ../../gcc/cp/parser.c:23312
0x9a391c cp_parser_initializer
        ../../gcc/cp/parser.c:23250
0x9cc4ab cp_parser_init_declarator
        ../../gcc/cp/parser.c:20943
0x9ac3cc cp_parser_simple_declaration
        ../../gcc/cp/parser.c:13811
0x9ae42d cp_parser_declaration_statement
        ../../gcc/cp/parser.c:13249
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.

My GCC version is
Using built-in specs.
COLLECT_GCC=g++
COLLECT_LTO_WRAPPER=/home/haoxin/corpus-compilers/gcc-trunk/gcc-master/build/libexec/gcc/x86_64-pc-linux-gnu/11.0.0/lto-wrapper
Target: x86_64-pc-linux-gnu
Configured with: ../configure
--prefix=/home/haoxin/corpus-compilers/gcc-trunk/gcc-master/build/
--enable-languages=c,c++ CC=gcc CXX=g++
Thread model: posix
Supported LTO compression algorithms: zlib
gcc version 11.0.0 20200801 (experimental) (GCC) 


Thanks,
Haoxin