[Bug c++/86881] New: tree check fail with flag Wshadow-compatible-local

[dcb314 at hotmail dot com]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=86881

            Bug ID: 86881
           Summary: tree check fail with flag Wshadow-compatible-local
           Product: gcc
           Version: 8.0
            Status: UNCONFIRMED
          Severity: normal
          Priority: P3
         Component: c++
          Assignee: unassigned at gcc dot gnu.org
          Reporter: dcb314 at hotmail dot com
  Target Milestone: ---

For this C++ code:

void a() {
  auto b([] {});
  if (0)
    auto b = 0;
}

compiled with recent gcc trunk and flag -Wshadow-compatible-local
as so:

$ ~/gcc/results.263341/bin/gcc -c -std=gnu++14   -Wshadow-compatible-local
bug454.cc

does this:

bug454.cc:4:10: internal compiler error: tree check: expected record_type or
uni
on_type or qual_union_type, have template_type_parm in lookup_base, at
cp/search
.c:198
     auto b = 0;
          ^
0x7619b8 tree_check_failed(tree_node const*, char const*, int, char const*,
...)
        ../../trunk/gcc/tree.c:9351
0x98faee tree_check3(tree_node*, char const*, int, char const*, tree_code,
tree_
code, tree_code)
        ../../trunk/gcc/tree.h:3154
0x98faee lookup_base(tree_node*, tree_node*, int, base_kind*, int)
        ../../trunk/gcc/cp/search.c:198
0x81442a build_user_type_conversion_1
        ../../trunk/gcc/cp/call.c:3782
0x815bc1 implicit_conversion
        ../../trunk/gcc/cp/call.c:1902
0x819d18 can_convert_arg(tree_node*, tree_node*, tree_node*, int, int)
        ../../trunk/gcc/cp/call.c:10673
0x8f4a4e check_local_shadow
        ../../trunk/gcc/cp/name-lookup.c:2737

The problem seems to have existed since before revision 262370.