From @geeknik

./perl -Dx -e 'END{}'

perl​: gv.c​:2380​: void Perl_gv_fullname4(SV *, const GV *, const char *, _Bool)​: Assertion `((((_gvstash)->sv_flags & (0x00004000|0x00008000)) == 0x00008000) && (((svtype)((_gvstash)->sv_flags & 0xff)) == SVt_PVGV || ((svtype)((_gvstash)->sv_flags & 0xff)) == SVt_PVLV))' failed.
Aborted

#0 0x00007ffff6cf2067 in __GI_raise (sig=sig@​entry=6) at ../nptl/sysdeps/unix/sysv/linux/raise.c​:56
#1 0x00007ffff6cf3448 in __GI_abort () at abort.c​:89
#2 0x00007ffff6ceb266 in __assert_fail_base (fmt=0x7ffff6e24238 "%s%s%s​:%u​: %s%sAssertion `%s' failed.\n%n",
  assertion=assertion@​entry=0x602a58 "((((_gvstash)->sv_flags & (0x00004000|0x00008000)) == 0x00008000) && (((svtype)((_gvstash)->sv_flags & 0xff)) == SVt_PVGV || ((svtype)((_gvstash)->sv_flags & 0xff)) == SVt_PVLV))", file=file@​entry=0x63f7a4 "gv.c", line=line@​entry=2380,
  function=function@​entry=0x645490 <__PRETTY_FUNCTION__.17492> "Perl_gv_fullname4") at assert.c​:92
#3 0x00007ffff6ceb312 in __GI___assert_fail (
  assertion=assertion@​entry=0x602a58 "((((_gvstash)->sv_flags & (0x00004000|0x00008000)) == 0x00008000) && (((svtype)((_gvstash)->sv_flags & 0xff)) == SVt_PVGV || ((svtype)((_gvstash)->sv_flags & 0xff)) == SVt_PVLV))", file=file@​entry=0x63f7a4 "gv.c", line=line@​entry=2380,
  function=function@​entry=0x645490 <__PRETTY_FUNCTION__.17492> "Perl_gv_fullname4") at assert.c​:101
#4 0x0000000000453dcf in Perl_gv_fullname4 (sv=sv@​entry=0x9278b0, gv=gv@​entry=0x927880, prefix=prefix@​entry=0x0, keepmain=keepmain@​entry=true) at gv.c​:2380
#5 0x00000000004ce175 in Perl_dump_sub_perl (gv=gv@​entry=0x927880, justperl=justperl@​entry=false) at dump.c​:615
#6 0x00000000004ce3cc in Perl_dump_sub (gv=gv@​entry=0x927880) at dump.c​:598
#7 0x00000000004240e8 in S_process_special_blocks (floor=floor@​entry=39, fullname=fullname@​entry=0x92c310 "END", gv=gv@​entry=0x927880, cv=cv@​entry=0x927850)
  at op.c​:8913
#8 0x000000000043fd24 in Perl_newATTRSUB_x (floor=<optimized out>, o=<optimized out>, proto=0x0, attrs=0x0, block=<optimized out>, o_is_gv=<optimized out>)
  at op.c​:8831
#9 0x000000000048cb32 in Perl_yyparse (gramtype=0) at perly.y​:297
#10 0x0000000000450cc8 in S_parse_body (env=env@​entry=0x0, xsinit=xsinit@​entry=0x421940 <xs_init>) at perl.c​:2373
#11 0x000000000045285d in perl_parse (my_perl=<optimized out>, xsinit=xsinit@​entry=0x421940 <xs_init>, argc=4, argv=0x7fffffffe6a8, env=env@​entry=0x0)
  at perl.c​:1689
#12 0x00000000004217b0 in main (argc=4, argv=0x7fffffffe6a8, env=0x7fffffffe6d0) at perlmain.c​:121

From zefram@fysh.org

Fixed by 27b4ba2.

-zefram

The RT System itself - Status changed from 'new' to 'open'

@iabyn - Status changed from 'open' to 'pending release'

From @khwilliamson

Thank you for filing this report. You have helped make Perl better.

With the release today of Perl 5.26.0, this and 210 other issues have been
resolved.

Perl 5.26.0 may be downloaded via​:
https://metacpan.org/release/XSAWYERX/perl-5.26.0

If you find that the problem persists, feel free to reopen this ticket.

@khwilliamson - Status changed from 'pending release' to 'resolved'