[Bug c++/87398] New: g++ ICE on valid code: tree check: expected record_type or union_type or qual_union_type, have array_type in cxx_eval_constant_expression, at cp/constexpr.c:4820

[helloqirun at gmail dot com]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=87398

            Bug ID: 87398
           Summary: g++ ICE on valid code: tree check: expected
                    record_type or union_type or qual_union_type, have
                    array_type in cxx_eval_constant_expression, at
                    cp/constexpr.c:4820
           Product: gcc
           Version: unknown
            Status: UNCONFIRMED
          Severity: normal
          Priority: P3
         Component: c++
          Assignee: unassigned at gcc dot gnu.org
          Reporter: helloqirun at gmail dot com
  Target Milestone: ---

It happens with flag "-std=c++2a". It appears to start with r264408.

$ g++-trunk -v
Using built-in specs.
COLLECT_GCC=g++-trunk
COLLECT_LTO_WRAPPER=/home/absozero/trunk/root-gcc/libexec/gcc/x86_64-pc-linux-gnu/9.0.0/lto-wrapper
Target: x86_64-pc-linux-gnu
Configured with: ../gcc/configure --prefix=/home/absozero/trunk/root-gcc
--enable-languages=c,c++ --disable-werror --enable-multilib
Thread model: posix
gcc version 9.0.0 20180923 (experimental) [trunk revision 264513] (GCC)


$ g++-trunk -std=c++2a abc.C
abc.C: In function ‘void c()’:
abc.C:7:20: internal compiler error: tree check: expected record_type or
union_type or qual_union_type, have array_type in cxx_eval_constant_expression,
at cp/constexpr.c:4820
7 |   int d(e[4][d].b());
  |                    ^
0x79a6c4 tree_check_failed(tree_node const*, char const*, int, char const*,
...)
        ../../gcc/gcc/tree.c:9369
0x880c98 tree_check3(tree_node*, char const*, int, char const*, tree_code,
tree_code, tree_code)
        ../../gcc/gcc/tree.h:3153
0x880c98 cxx_eval_constant_expression
        ../../gcc/gcc/cp/constexpr.c:4820
0x87bdd7 cxx_eval_call_expression
        ../../gcc/gcc/cp/constexpr.c:1508
0x87df1d cxx_eval_constant_expression
        ../../gcc/gcc/cp/constexpr.c:4284
0x8832fe cxx_eval_outermost_constant_expr
        ../../gcc/gcc/cp/constexpr.c:5018
0x886518 maybe_constant_value(tree_node*, tree_node*)
        ../../gcc/gcc/cp/constexpr.c:5245
0x8963d1 cp_fully_fold(tree_node*)
        ../../gcc/gcc/cp/cp-gimplify.c:2120
0x89e28f cp_convert_and_check(tree_node*, tree_node*, int)
        ../../gcc/gcc/cp/cvt.c:656
0x84c3b5 convert_like_real
        ../../gcc/gcc/cp/call.c:7219
0x84d508 perform_implicit_conversion_flags(tree_node*, tree_node*, int, int)
        ../../gcc/gcc/cp/call.c:10938
0xa15311 digest_init_r
        ../../gcc/gcc/cp/typeck2.c:1195
0xa17f02 digest_init_flags(tree_node*, tree_node*, int, int)
        ../../gcc/gcc/cp/typeck2.c:1211
0xa17f02 store_init_value(tree_node*, tree_node*, vec<tree_node*, va_gc,
vl_embed>**, int)
        ../../gcc/gcc/cp/typeck2.c:808
0x8ae4ed check_initializer
        ../../gcc/gcc/cp/decl.c:6481
0x8c657f cp_finish_decl(tree_node*, tree_node*, bool, tree_node*, int)
        ../../gcc/gcc/cp/decl.c:7152
0x961466 cp_parser_init_declarator
        ../../gcc/gcc/cp/parser.c:19893
0x968653 cp_parser_simple_declaration
        ../../gcc/gcc/cp/parser.c:13189
0x96a1b9 cp_parser_declaration_statement
        ../../gcc/gcc/cp/parser.c:12608
0x949023 cp_parser_statement
        ../../gcc/gcc/cp/parser.c:10953
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.

$ cat abc.C
class a {
public:
  virtual long b();
};
void c() {
  a e[5][2];
  int d(e[4][d].b());
}