[Bug c++/84708] New: internal compiler error: in lambda_expr_this_capture, at cp/lambda.c:772

["vegard.nossum at gmail dot com" <gcc-bugzilla at gcc dot gnu dot org>]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=84708

            Bug ID: 84708
           Summary: internal compiler error: in lambda_expr_this_capture,
                    at cp/lambda.c:772
           Product: gcc
           Version: 8.0.1
            Status: UNCONFIRMED
          Severity: normal
          Priority: P3
         Component: c++
          Assignee: unassigned at gcc dot gnu.org
          Reporter: vegard.nossum at gmail dot com
                CC: webrown.cpp at gmail dot com
  Target Milestone: ---

Input:

int y;

void a() {
  struct {
    int b = ([] {
      decltype(b) x = y;
      return y;
    }) ();
  } z;
}

Output:

$ xgcc -x c++ -S  -
<stdin>: In lambda function:
<stdin>:6:16: internal compiler error: in lambda_expr_this_capture, at
cp/lambda.c:772
0xd491ff lambda_expr_this_capture(tree_node*, bool)
        /home/vegard/git/gcc/gcc/cp/lambda.c:770
0xd4980c maybe_resolve_dummy(tree_node*, bool)
        /home/vegard/git/gcc/gcc/cp/lambda.c:879
0x12acfc9 finish_non_static_data_member(tree_node*, tree_node*, tree_node*)
        /home/vegard/git/gcc/gcc/cp/semantics.c:1788
0x12b23d2 finish_id_expression(tree_node*, tree_node*, tree_node*, cp_id_kind*,
bool, bool, bool*, bool, bool, bool, bool, char const**, unsigned int)
        /home/vegard/git/gcc/gcc/cp/semantics.c:3719
0xf7f285 cp_parser_decltype_expr
        /home/vegard/git/gcc/gcc/cp/parser.c:13999
0xf7f285 cp_parser_decltype
        /home/vegard/git/gcc/gcc/cp/parser.c:14133
0xf31fa7 cp_parser_simple_type_specifier
        /home/vegard/git/gcc/gcc/cp/parser.c:17063
0xf26f2d cp_parser_type_specifier
        /home/vegard/git/gcc/gcc/cp/parser.c:16850
0xf8c7ba cp_parser_decl_specifier_seq
        /home/vegard/git/gcc/gcc/cp/parser.c:13627
0xfa7ca0 cp_parser_simple_declaration
        /home/vegard/git/gcc/gcc/cp/parser.c:12936
0xfafbc8 cp_parser_block_declaration
        /home/vegard/git/gcc/gcc/cp/parser.c:12881
0xfb2094 cp_parser_declaration_statement
        /home/vegard/git/gcc/gcc/cp/parser.c:12474
0xefef9b cp_parser_statement
        /home/vegard/git/gcc/gcc/cp/parser.c:10923
0xf02a5b cp_parser_statement_seq_opt
        /home/vegard/git/gcc/gcc/cp/parser.c:11272
0xfd3951 cp_parser_lambda_body
        /home/vegard/git/gcc/gcc/cp/parser.c:10683
0xfd3951 cp_parser_lambda_expression
        /home/vegard/git/gcc/gcc/cp/parser.c:10184
0xf390e4 cp_parser_primary_expression
        /home/vegard/git/gcc/gcc/cp/parser.c:5259
0xf7abbb cp_parser_postfix_expression
        /home/vegard/git/gcc/gcc/cp/parser.c:7028
0xf2e927 cp_parser_unary_expression
        /home/vegard/git/gcc/gcc/cp/parser.c:8320
0xec435a cp_parser_cast_expression
        /home/vegard/git/gcc/gcc/cp/parser.c:9088

$ xgcc --version
xgcc (GCC) 8.0.1 20180303 (experimental)

Built from git 0d86c284d085d29782d862600a79aa1ff0ee0c47 (r258221).

I'm not sure if it's really valid code or not, but clang (with -std=c++11)
compiles the test case without any errors.

Test case was minimised by C-Reduce.

Looks related (identical?) to bug #79651 and bug #83268, but the test case
looks smaller in any case.