[Bug c++/96652] New: Segmentation fault with instantiate_class_template_1

[tangyixuan at mail dot dlut.edu.cn]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=96652

            Bug ID: 96652
           Summary: Segmentation fault with instantiate_class_template_1
           Product: gcc
           Version: 10.0
            Status: UNCONFIRMED
          Severity: normal
          Priority: P3
         Component: c++
          Assignee: unassigned at gcc dot gnu.org
          Reporter: tangyixuan at mail dot dlut.edu.cn
  Target Milestone: ---

g++ crashes on the following code, while clang++ compiles successfully:

$: cat s.cpp

struct A {};
template <typename T>
struct B
{
    A a;
    friend decltype(a);
};

int main()
{
    A a;
    B<int> b; 
}

$: g++ -std=c++11 -c s.cpp

s.cpp: In instantiation of ‘struct B<int>’:
s.cpp:12:12:   required from here
s.cpp:5:7: internal compiler error: Segmentation fault
    5 |     A a;
      |       ^
0xc6a68f crash_signal
        ../../gcc-11-20200628/gcc/toplev.c:328
0x77745a instantiate_class_template_1
        ../../gcc-11-20200628/gcc/cp/pt.c:11974
0x778202 instantiate_class_template(tree_node*)
        ../../gcc-11-20200628/gcc/cp/pt.c:12098
0x7a7d8d complete_type(tree_node*)
        ../../gcc-11-20200628/gcc/cp/typeck.c:137
0x7a7d8d complete_type(tree_node*)
        ../../gcc-11-20200628/gcc/cp/typeck.c:111
0x6a031b start_decl_1(tree_node*, bool)
        ../../gcc-11-20200628/gcc/cp/decl.c:5490
0x6b0bef start_decl(cp_declarator const*, cp_decl_specifier_seq*, int,
tree_node*, tree_node*, tree_node**)
        ../../gcc-11-20200628/gcc/cp/decl.c:5453
0x738d3e cp_parser_init_declarator
        ../../gcc-11-20200628/gcc/cp/parser.c:20818
0x71c052 cp_parser_simple_declaration
        ../../gcc-11-20200628/gcc/cp/parser.c:13785
0x71dbdd cp_parser_declaration_statement
        ../../gcc-11-20200628/gcc/cp/parser.c:13217
0x71e7b0 cp_parser_statement
        ../../gcc-11-20200628/gcc/cp/parser.c:11523
0x71f5c8 cp_parser_statement_seq_opt
        ../../gcc-11-20200628/gcc/cp/parser.c:11889
0x71f680 cp_parser_compound_statement
        ../../gcc-11-20200628/gcc/cp/parser.c:11839
0x735280 cp_parser_function_body
        ../../gcc-11-20200628/gcc/cp/parser.c:23116
0x735280 cp_parser_ctor_initializer_opt_and_function_body
        ../../gcc-11-20200628/gcc/cp/parser.c:23167
0x73887d cp_parser_function_definition_after_declarator
        ../../gcc-11-20200628/gcc/cp/parser.c:29063
0x73975f cp_parser_function_definition_from_specifiers_and_declarator
        ../../gcc-11-20200628/gcc/cp/parser.c:28979
0x73975f cp_parser_init_declarator
        ../../gcc-11-20200628/gcc/cp/parser.c:20722
0x71c052 cp_parser_simple_declaration
        ../../gcc-11-20200628/gcc/cp/parser.c:13785
0x741e16 cp_parser_declaration
        ../../gcc-11-20200628/gcc/cp/parser.c:13484
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Please include the complete backtrace with any bug report.
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