[Bug c++/85140] New: ICE with invalid use of alignas

[reichelt at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=85140

            Bug ID: 85140
           Summary: ICE with invalid use of alignas
           Product: gcc
           Version: 8.0
            Status: UNCONFIRMED
          Keywords: error-recovery, ice-on-invalid-code
          Severity: normal
          Priority: P3
         Component: c++
          Assignee: unassigned at gcc dot gnu.org
          Reporter: reichelt at gcc dot gnu.org
  Target Milestone: ---

The following invalid coide snippet triggers an ICE since GCC 4.8.0:

=============================
namespace N alignas() {}
=============================

bug.cc:1:21: error: expected primary-expression before ')' token
 namespace N alignas() {}
                     ^
bug.cc:1:24: internal compiler error: tree check: expected tree_list, have
error_mark in get_attribute_name, at attribs.c:835
 namespace N alignas() {}
                        ^
0x78c848 tree_check_failed(tree_node const*, char const*, int, char const*,
...)
        ../../gcc/gcc/tree.c:9322
0x9fa8a5 tree_check(tree_node const*, char const*, int, char const*, tree_code)
        ../../gcc/gcc/tree.h:3391
0x9fa8a5 get_attribute_name(tree_node const*)
        ../../gcc/gcc/attribs.c:835
0x8ffbad handle_namespace_attrs(tree_node*, tree_node*)
        ../../gcc/gcc/cp/name-lookup.c:5049
0x9496bf cp_parser_namespace_definition
        ../../gcc/gcc/cp/parser.c:18585
0x948cd3 cp_parser_declaration
        ../../gcc/gcc/cp/parser.c:12762
0x948fd1 cp_parser_declaration_seq_opt
        ../../gcc/gcc/cp/parser.c:12658
0x9492c4 cp_parser_translation_unit
        ../../gcc/gcc/cp/parser.c:4563
0x9492c4 c_parse_file()
        ../../gcc/gcc/cp/parser.c:39024
0xa48b26 c_common_parse_file()
        ../../gcc/gcc/c-family/c-opts.c:1132
Please submit a full bug report, [etc.]