[Bug c++/88222] New: ubsan error at cp/decl.c for broken code

[dcb314 at hotmail dot com]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=88222

            Bug ID: 88222
           Summary: ubsan error at cp/decl.c for broken code
           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 broken C++ code:

typedef char a[];

class S {
        a : 4;
};

recent gcc built with ubsan does this:

../../trunk/gcc/cp/decl.c:12225:26: runtime error: member access within null
pointer of type 'const struct cp_declarator'
bug483.cc:4:6: internal compiler error: Segmentation fault
    4 |  a : 4;
      |      ^
0x276a29f crash_signal
        ../../trunk/gcc/toplev.c:326
0xa777c5 grokdeclarator(cp_declarator const*, cp_decl_specifier_seq*,
decl_context, int, tree_node**)
        ../../trunk/gcc/cp/decl.c:12225

Also:

/home/dcb/gcc/results.265631.ubsan/bin/gcc
bug483.cc:4:6: error: bit-field ‘<anonymous>’ with non-integral type
/home/dcb/gcc/results.265683.asan/bin/gcc
bug483.cc:4:6: internal compiler error: Segmentation fault

So the problem seems to occur sometime between revisions 265631 and 265683.