AND type checks for subtypeness

[Thomas Bartscher]

A type check like this
> (typep x '(and vector (not string)))
fails with the error
#<NEGATION-TYPE (NOT (VECTOR STRING))> is not a subtype of VECTOR

While that is certainly true, this seems overzealous – the intersection of these types isn't empty and the type declaration should be absolutely valid. The assumption that in an intersection type one type needs to be a subtype of the other is false.

This has been done on Linux thomas 4.6.0-1-amd64 #1 SMP Debian 4.6.4-1 (2016-07-18) x86_64 GNU/Linux with SBCL 1.3.7.61-5fc41bd.

* *features*
(:HTML-TEMPLATE :CL-FAD :BORDEAUX-THREADS ALEXANDRIA.0.DEV::SEQUENCE-EMPTYP
 :THREAD-SUPPORT :QUICKLISP :SB-BSD-SOCKETS-ADDRINFO :ASDF-PACKAGE-SYSTEM
 :ASDF3.1 :ASDF3 :ASDF2 :ASDF :OS-UNIX :NON-BASE-CHARS-EXIST-P :ASDF-UNICODE
 :64-BIT :64-BIT-REGISTERS :ALIEN-CALLBACKS :ANSI-CL :ASH-RIGHT-VOPS
 :C-STACK-IS-CONTROL-STACK :COMMON-LISP :COMPARE-AND-SWAP-VOPS
 :COMPLEX-FLOAT-VOPS :CYCLE-COUNTER :ELF :FLOAT-EQL-VOPS
 :FP-AND-PC-STANDARD-SAVE :GENCGC :IEEE-FLOATING-POINT :INLINE-CONSTANTS
 :INTEGER-EQL-VOP :LARGEFILE :LINKAGE-TABLE :LINUX :LITTLE-ENDIAN
 :MEMORY-BARRIER-VOPS :MULTIPLY-HIGH-VOPS :OS-PROVIDES-BLKSIZE-T
 :OS-PROVIDES-DLADDR :OS-PROVIDES-DLOPEN :OS-PROVIDES-GETPROTOBY-R
 :OS-PROVIDES-POLL :OS-PROVIDES-PUTWC :OS-PROVIDES-SUSECONDS-T
 :PACKAGE-LOCAL-NICKNAMES :PRECISE-ARG-COUNT-ERROR :RAW-INSTANCE-INIT-VOPS
 :SB-AFTER-XC-CORE :SB-CORE-COMPRESSION :SB-CORE-COMPRESSION :SB-DOC :SB-EVAL
 :SB-FUTEX :SB-LDB :SB-PACKAGE-LOCKS :SB-SIMD-PACK :SB-SOURCE-LOCATIONS
 :SB-TEST :SB-THREAD :SB-UNICODE :SB-XREF-FOR-INTERNALS :SB-XREF-FOR-INTERNALS
 :SBCL :STACK-ALLOCATABLE-CLOSURES :STACK-ALLOCATABLE-FIXED-OBJECTS
 :STACK-ALLOCATABLE-LISTS :STACK-ALLOCATABLE-VECTORS
 :STACK-GROWS-DOWNWARD-NOT-UPWARD :SYMBOL-INFO-VOPS :UNIX
 :UNWIND-TO-FRAME-AND-CALL-VOP :X86-64)

[Jan Moringen (scymtym)]

> with SBCL 1.3.7.61-5fc41bd

You appear to be using an unreleased version of SBCL. The problem you describe has likely been fixed a couple of commits later in

  a6d81f1 Fix sequence type derivation in the presence of negation types.

just before the 1.3.8 release. Please try to reproduce the problem with a released version or the current master.

[Thomas Bartscher (thomas-bartscher-h)]

I am sorry. Yes, that bug has been fixed.