&REST with SAFETY 0: call to undefined function SB-C:%MORE-ARG-VALUES

[Lutz Euler]

(defun f (&rest rest)
  (declare (optimize (safety 0)))
  (apply #'cons rest))

(f 'car 'cdr)

debugger invoked on a UNDEFINED-FUNCTION in thread #<THREAD
                                                     "initial thread" RUNNING
                                                      {1002919711}>:
  The function SB-C:%MORE-ARG-VALUES is undefined.

Type HELP for debugger help, or (SB-EXT:QUIT) to exit from SBCL.

restarts (invokable by number or by possibly-abbreviated name):
  0: [ABORT] Exit debugger, returning to top level.

("bogus stack frame")
0]

(lisp-implementation-version)

"1.0.50.46-d5ec4e5"

This works OK without the SAFETY 0 declaration,
or, fwiw, with SAFETY 1.

This is a regression. It worked up to 1.0.48.24.
1.0.48.25 is the first broken version.
Start of the commit message:

1.0.48.25: automatic &rest to &more conversion

 lp#504575

 Automatically convert

   (values-list rest-arg)
 to
   (%more-arg-values more-context 0 more-count)

I found this while trying to build SBCL with a
PROCLAIM-TARGET-OPTIMIZATION of SAFETY 0
as this yields a faster compiler.
This crashes into ldb in warm init due to
the definition of BACKQ-CONS which has
much similarity to the reduced test case above:

//doing warm init - compilation phase
This is SBCL 1.0.50.46.safety0.1, an implementation of ANSI
Common Lisp.
More information about SBCL is available at <http://www.sbcl.org/>.

SBCL is free software, provided as is, with absolutely no warranty.
It is mostly in the public domain; some portions are provided under
BSD-style licenses. See the CREDITS and COPYING files in the
distribution for more information.
internal error #23 (An attempt was made to use an undefined FDEFINITION.)
    SC: 21, Offset: 0 $1= 0x10000806ef: other pointer
fatal error encountered in SBCL pid 11098(tid 140737353930528):
internal error too early in init, can't recover

Welcome to LDB, a low-level debugger for the Lisp runtime environment.
ldb> backtrace
Backtrace:
   0: Foreign function lose, fp = 0x7ffff6d47640, ra = 0x40f788
   1: Foreign function interrupt_internal_error, fp = 0x7ffff6d47710,
        ra = 0x412a58
   2: Foreign function handle_trap, fp = 0x7ffff6d477e0, ra = 0x415770
   3: Foreign function (null), fp = 0x7ffff6d478b0, ra = 0x410401
   4: Foreign function (null), fp = 0x7ffff6d47d30, ra = 0x7ffff79c9c60
   5: (SB!C::&MORE-PROCESSOR SB!IMPL::BACKQ-CONS)
   6: SB!KERNEL::INITIAL-HANDLER-CLUSTERS
   7: (SB!C::TOP-LEVEL-FORM ())
   8: SB!KERNEL::!COLD-INIT
ldb> print 0x10000806ef
$1= 0x10000806ef: other pointer
     header: 0x0000035e: fdefn
$2= name: 0x100001f0ff: %MORE-ARG-VALUES
$nil= function: 0x20100017: NIL
     raw_addr: 0x00425020: 1086472
ldb>

Sorry, I have no fix.

Kind regards,

Lutz

[Paul Khuong (pvk)]

Fixed in 86d50ba Fix automatic &rest to &more conversion in unsafe code.

Thanks for the tiny test case!