0.pre8.98:

[sbcl.git] / src / code / late-type.lisp

diff --git a/src/code/late-type.lisp b/src/code/late-type.lisp
index 1563ca5..e4a17df 100644 (file)
--- a/src/code/late-type.lisp
+++ b/src/code/late-type.lisp
@@ -22,14 +22,8 @@
 
 ;;; ### Remaining incorrectnesses:
 ;;;
 
 ;;; ### Remaining incorrectnesses:
 ;;;

-;;; TYPE-UNION (and the OR type) doesn't properly canonicalize an
-;;; exhaustive partition or coalesce contiguous ranges of numeric
-;;; types.
-;;;

 ;;; There are all sorts of nasty problems with open bounds on FLOAT
 ;;; types (and probably FLOAT types in general.)
 ;;; There are all sorts of nasty problems with open bounds on FLOAT
 ;;; types (and probably FLOAT types in general.)

-;;;
-;;; RATIO and BIGNUM are not recognized as numeric types.

 
 ;;; FIXME: This really should go away. Alas, it doesn't seem to be so
 ;;; simple to make it go away.. (See bug 123 in BUGS file.)
 
 ;;; FIXME: This really should go away. Alas, it doesn't seem to be so
 ;;; simple to make it go away.. (See bug 123 in BUGS file.)

@@ -65,21 +59,30 @@
 ;;; This is used by !DEFINE-SUPERCLASSES to define the SUBTYPE-ARG1
 ;;; method. INFO is a list of conses
 ;;;   (SUPERCLASS-CLASS . {GUARD-TYPE-SPECIFIER | NIL}).
 ;;; This is used by !DEFINE-SUPERCLASSES to define the SUBTYPE-ARG1
 ;;; method. INFO is a list of conses
 ;;;   (SUPERCLASS-CLASS . {GUARD-TYPE-SPECIFIER | NIL}).

-;;; This will never be called with a hairy type as TYPE2, since the
-;;; hairy type TYPE2 method gets first crack.

 (defun !has-superclasses-complex-subtypep-arg1 (type1 type2 info)
 (defun !has-superclasses-complex-subtypep-arg1 (type1 type2 info)

-  (values
-   (and (sb!xc:typep type2 'sb!xc:class)
-       (dolist (x info nil)
-         (when (or (not (cdr x))
-                   (csubtypep type1 (specifier-type (cdr x))))
-           (return
-            (or (eq type2 (car x))
-                (let ((inherits (layout-inherits (class-layout (car x)))))
-                  (dotimes (i (length inherits) nil)
-                    (when (eq type2 (layout-class (svref inherits i)))
-                      (return t)))))))))
-   t))
+  ;; If TYPE2 might be concealing something related to our class
+  ;; hierarchy
+  (if (type-might-contain-other-types-p type2)
+      ;; too confusing, gotta punt
+      (values nil nil)
+      ;; ordinary case expected by old CMU CL code, where the taxonomy
+      ;; of TYPE2's representation accurately reflects the taxonomy of
+      ;; the underlying set
+      (values
+       ;; FIXME: This old CMU CL code probably deserves a comment
+       ;; explaining to us mere mortals how it works...
+       (and (sb!xc:typep type2 'classoid)
+           (dolist (x info nil)
+             (when (or (not (cdr x))
+                       (csubtypep type1 (specifier-type (cdr x))))
+               (return
+                (or (eq type2 (car x))
+                    (let ((inherits (layout-inherits
+                                     (classoid-layout (car x)))))
+                      (dotimes (i (length inherits) nil)
+                        (when (eq type2 (layout-classoid (svref inherits i)))
+                          (return t)))))))))
+       t)))

 
 ;;; This function takes a list of specs, each of the form
 ;;;    (SUPERCLASS-NAME &OPTIONAL GUARD).
 
 ;;; This function takes a list of specs, each of the form
 ;;;    (SUPERCLASS-NAME &OPTIONAL GUARD).

@@ -102,7 +105,7 @@
                              (destructuring-bind
                                  (super &optional guard)
                                  spec
                              (destructuring-bind
                                  (super &optional guard)
                                  spec

-                               (cons (sb!xc:find-class super) guard)))
+                               (cons (find-classoid super) guard)))

                            ',specs)))
         (setf (type-class-complex-subtypep-arg1 ,type-class)
               (lambda (type1 type2)
                            ',specs)))
         (setf (type-class-complex-subtypep-arg1 ,type-class)
               (lambda (type1 type2)

@@ -205,11 +208,52 @@
            (type-specifier
             (fun-type-returns type)))))
 
            (type-specifier
             (fun-type-returns type)))))
 

-;;; Since all function types are equivalent to FUNCTION, they are all
-;;; subtypes of each other.
+;;; The meaning of this is a little confused. On the one hand, all
+;;; function objects are represented the same way regardless of the
+;;; arglists and return values, and apps don't get to ask things like
+;;; (TYPEP #'FOO (FUNCTION (FIXNUM) *)) in any meaningful way. On the
+;;; other hand, Python wants to reason about function types. So...

 (!define-type-method (function :simple-subtypep) (type1 type2)
 (!define-type-method (function :simple-subtypep) (type1 type2)

-  (declare (ignore type1 type2))
-  (values t t))
+ (flet ((fun-type-simple-p (type)
+          (not (or (fun-type-rest type)
+                   (fun-type-keyp type))))
+        (every-csubtypep (types1 types2)
+          (loop
+             for a1 in types1
+             for a2 in types2
+             do (multiple-value-bind (res sure-p)
+                    (csubtypep a1 a2)
+                  (unless res (return (values res sure-p))))
+             finally (return (values t t)))))
+   (and/type (values-subtypep (fun-type-returns type1)
+                              (fun-type-returns type2))
+             (cond ((fun-type-wild-args type2) (values t t))
+                   ((fun-type-wild-args type1)
+                    (cond ((fun-type-keyp type2) (values nil nil))
+                          ((not (fun-type-rest type2)) (values nil t))
+                          ((not (null (fun-type-required type2))) (values nil t))
+                          (t (and/type (type= *universal-type* (fun-type-rest type2))
+                                       (every/type #'type= *universal-type*
+                                                   (fun-type-optional type2))))))
+                   ((not (and (fun-type-simple-p type1)
+                              (fun-type-simple-p type2)))
+                    (values nil nil))
+                   (t (multiple-value-bind (min1 max1) (fun-type-nargs type1)
+                        (multiple-value-bind (min2 max2) (fun-type-nargs type2)
+                          (cond ((or (> max1 max2) (< min1 min2))
+                                 (values nil t))
+                                ((and (= min1 min2) (= max1 max2))
+                                 (and/type (every-csubtypep (fun-type-required type1)
+                                                            (fun-type-required type2))
+                                           (every-csubtypep (fun-type-optional type1)
+                                                            (fun-type-optional type2))))
+                                (t (every-csubtypep
+                                    (concatenate 'list
+                                                 (fun-type-required type1)
+                                                 (fun-type-optional type1))
+                                    (concatenate 'list
+                                                 (fun-type-required type2)
+                                                 (fun-type-optional type2))))))))))))

 
 (!define-superclasses function ((function)) !cold-init-forms)
 
 
 (!define-superclasses function ((function)) !cold-init-forms)
 

@@ -229,12 +273,12 @@
 (!define-type-class constant :inherits values)
 
 (!define-type-method (constant :unparse) (type)
 (!define-type-class constant :inherits values)
 
 (!define-type-method (constant :unparse) (type)

-  `(constant-argument ,(type-specifier (constant-type-type type))))
+  `(constant-arg ,(type-specifier (constant-type-type type))))

 
 (!define-type-method (constant :simple-=) (type1 type2)
   (type= (constant-type-type type1) (constant-type-type type2)))
 
 
 (!define-type-method (constant :simple-=) (type1 type2)
   (type= (constant-type-type type1) (constant-type-type type2)))
 

-(!def-type-translator constant-argument (type)
+(!def-type-translator constant-arg (type)

   (make-constant-type :type (specifier-type type)))
 
 ;;; Given a LAMBDA-LIST-like values type specification and an ARGS-TYPE
   (make-constant-type :type (specifier-type type)))
 
 ;;; Given a LAMBDA-LIST-like values type specification and an ARGS-TYPE

@@ -242,13 +286,17 @@
 ;;; used for both FUNCTION and VALUES types.
 (declaim (ftype (function (list args-type) (values)) parse-args-types))
 (defun parse-args-types (lambda-list result)
 ;;; used for both FUNCTION and VALUES types.
 (declaim (ftype (function (list args-type) (values)) parse-args-types))
 (defun parse-args-types (lambda-list result)

-  (multiple-value-bind (required optional restp rest keyp keys allowp aux)
-      (parse-lambda-list lambda-list)
-    (when aux
+  (multiple-value-bind (required optional restp rest keyp keys allowp auxp aux)
+      (parse-lambda-list-like-thing lambda-list)
+    (declare (ignore aux)) ; since we require AUXP=NIL
+    (when auxp

       (error "&AUX in a FUNCTION or VALUES type: ~S." lambda-list))
       (error "&AUX in a FUNCTION or VALUES type: ~S." lambda-list))

-    (setf (args-type-required result) (mapcar #'specifier-type required))
-    (setf (args-type-optional result) (mapcar #'specifier-type optional))
-    (setf (args-type-rest result) (if restp (specifier-type rest) nil))
+    (setf (args-type-required result)
+          (mapcar #'single-value-specifier-type required))
+    (setf (args-type-optional result)
+          (mapcar #'single-value-specifier-type optional))
+    (setf (args-type-rest result)
+          (if restp (single-value-specifier-type rest) nil))

     (setf (args-type-keyp result) keyp)
     (collect ((key-info))
       (dolist (key keys)
     (setf (args-type-keyp result) keyp)
     (collect ((key-info))
       (dolist (key keys)

@@ -259,7 +307,7 @@
            (error "~@<repeated keyword ~S in lambda list: ~2I~_~S~:>"
                   kwd lambda-list))
          (key-info (make-key-info :name kwd
            (error "~@<repeated keyword ~S in lambda list: ~2I~_~S~:>"
                   kwd lambda-list))
          (key-info (make-key-info :name kwd

-                                  :type (specifier-type (second key))))))
+                                  :type (single-value-specifier-type (second key))))))

       (setf (args-type-keywords result) (key-info)))
     (setf (args-type-allowp result) allowp)
     (values)))
       (setf (args-type-keywords result) (key-info)))
     (setf (args-type-allowp result) allowp)
     (values)))

@@ -301,7 +349,7 @@
     res))
 
 (!def-type-translator values (&rest values)
     res))
 
 (!def-type-translator values (&rest values)

-  (let ((res (make-values-type)))
+  (let ((res (%make-values-type)))

     (parse-args-types values res)
     res))
 \f
     (parse-args-types values res)
     res))
 \f

@@ -393,7 +441,7 @@
                                       :initial-element rest2)))
            exact)))
 
                                       :initial-element rest2)))
            exact)))
 

-;;; If Type isn't a values type, then make it into one:
+;;; If TYPE isn't a values type, then make it into one:

 ;;;    <type>  ==>  (values type &rest t)
 (defun coerce-to-values (type)
   (declare (type ctype type))
 ;;;    <type>  ==>  (values type &rest t)
 (defun coerce-to-values (type)
   (declare (type ctype type))

@@ -427,6 +475,8 @@
 (defun args-type-op (type1 type2 operation nreq default-type)
   (declare (type ctype type1 type2 default-type)
           (type function operation nreq))
 (defun args-type-op (type1 type2 operation nreq default-type)
   (declare (type ctype type1 type2 default-type)
           (type function operation nreq))

+  (when (eq type1 type2)
+    (values type1 t))

   (if (or (values-type-p type1) (values-type-p type2))
       (let ((type1 (coerce-to-values type1))
            (type2 (coerce-to-values type2)))
   (if (or (values-type-p type1) (values-type-p type2))
       (let ((type1 (coerce-to-values type1))
            (type2 (coerce-to-values type2)))

@@ -560,8 +610,7 @@
             (eq type1 *empty-type*)
             (eq type2 *wild-type*))
         (values t t))
             (eq type1 *empty-type*)
             (eq type2 *wild-type*))
         (values t t))

-       ((or (eq type1 *wild-type*)
-            (eq type2 *empty-type*))
+       ((eq type1 *wild-type*)

         (values nil t))
        (t
         (!invoke-type-method :simple-subtypep :complex-subtypep-arg2
         (values nil t))
        (t
         (!invoke-type-method :simple-subtypep :complex-subtypep-arg2

@@ -569,12 +618,13 @@
                              :complex-arg1 :complex-subtypep-arg1))))
 
 ;;; Just parse the type specifiers and call CSUBTYPE.
                              :complex-arg1 :complex-subtypep-arg1))))
 
 ;;; Just parse the type specifiers and call CSUBTYPE.

-(defun sb!xc:subtypep (type1 type2)
+(defun sb!xc:subtypep (type1 type2 &optional environment)

   #!+sb-doc
   "Return two values indicating the relationship between type1 and type2.
   If values are T and T, type1 definitely is a subtype of type2.
   If values are NIL and T, type1 definitely is not a subtype of type2.
   If values are NIL and NIL, it couldn't be determined."
   #!+sb-doc
   "Return two values indicating the relationship between type1 and type2.
   If values are T and T, type1 definitely is a subtype of type2.
   If values are NIL and T, type1 definitely is not a subtype of type2.
   If values are NIL and NIL, it couldn't be determined."

+  (declare (ignore environment))

   (csubtypep (specifier-type type1) (specifier-type type2)))
 
 ;;; If two types are definitely equivalent, return true. The second
   (csubtypep (specifier-type type1) (specifier-type type2)))
 
 ;;; If two types are definitely equivalent, return true. The second

@@ -633,6 +683,8 @@
   (declare (type ctype type1 type2))
   (cond ((eq type1 type2)
         type1)
   (declare (type ctype type1 type2))
   (cond ((eq type1 type2)
         type1)

+       ((csubtypep type1 type2) type2)
+       ((csubtypep type2 type1) type1)

        ((or (union-type-p type1)
             (union-type-p type2))
         ;; Unions of UNION-TYPE should have the UNION-TYPE-TYPES
        ((or (union-type-p type1)
             (union-type-p type2))
         ;; Unions of UNION-TYPE should have the UNION-TYPE-TYPES

@@ -685,6 +737,9 @@
              ((type1 eq) (type2 eq))
   (declare (type ctype type1 type2))
   (cond ((eq type1 type2)
              ((type1 eq) (type2 eq))
   (declare (type ctype type1 type2))
   (cond ((eq type1 type2)

+        ;; FIXME: For some reason, this doesn't catch e.g. type1 =
+        ;; type2 = (SPECIFIER-TYPE
+        ;; 'SOME-UNKNOWN-TYPE). Investigate. - CSR, 2002-04-10

         type1)
        ((or (intersection-type-p type1)
             (intersection-type-p type2))
         type1)
        ((or (intersection-type-p type1)
             (intersection-type-p type2))

@@ -744,7 +799,17 @@
     (let ((res (specifier-type spec)))
       (unless (unknown-type-p res)
        (setf (info :type :builtin spec) res)
     (let ((res (specifier-type spec)))
       (unless (unknown-type-p res)
        (setf (info :type :builtin spec) res)

-       (setf (info :type :kind spec) :primitive))))
+       ;; KLUDGE: the three copies of this idiom in this file (and
+       ;; the one in class.lisp as at sbcl-0.7.4.1x) should be
+       ;; coalesced, or perhaps the error-detecting code that
+       ;; disallows redefinition of :PRIMITIVE types should be
+       ;; rewritten to use *TYPE-SYSTEM-FINALIZED* (rather than
+       ;; *TYPE-SYSTEM-INITIALIZED*). The effect of this is not to
+       ;; cause redefinition errors when precompute-types is called
+       ;; for a second time while building the target compiler using
+       ;; the cross-compiler. -- CSR, trying to explain why this
+       ;; isn't completely wrong, 2002-06-07
+       (setf (info :type :kind spec) #+sb-xc-host :defined #-sb-xc-host :primitive))))

   (values))
 \f
 ;;;; general TYPE-UNION and TYPE-INTERSECTION operations
   (values))
 \f
 ;;;; general TYPE-UNION and TYPE-INTERSECTION operations

@@ -759,7 +824,7 @@
 (defun accumulate1-compound-type (type types %compound-type-p simplify2)
   (declare (type ctype type))
   (declare (type (vector ctype) types))
 (defun accumulate1-compound-type (type types %compound-type-p simplify2)
   (declare (type ctype type))
   (declare (type (vector ctype) types))

-  (declare (type function simplify2))
+  (declare (type function %compound-type-p simplify2))

   ;; Any input object satisfying %COMPOUND-TYPE-P should've been
   ;; broken into components before it reached us.
   (aver (not (funcall %compound-type-p type)))
   ;; Any input object satisfying %COMPOUND-TYPE-P should've been
   ;; broken into components before it reached us.
   (aver (not (funcall %compound-type-p type)))

@@ -800,6 +865,7 @@
 (defun simplified-compound-types (input-types %compound-type-p simplify2)
   (let ((simplified-types (make-array (length input-types)
                                      :fill-pointer 0
 (defun simplified-compound-types (input-types %compound-type-p simplify2)
   (let ((simplified-types (make-array (length input-types)
                                      :fill-pointer 0

+                                     :adjustable t

                                      :element-type 'ctype
                                      ;; (This INITIAL-ELEMENT shouldn't
                                      ;; matter, but helps avoid type
                                      :element-type 'ctype
                                      ;; (This INITIAL-ELEMENT shouldn't
                                      ;; matter, but helps avoid type

@@ -815,7 +881,7 @@
 ;;; shared logic for unions and intersections: Make a COMPOUND-TYPE
 ;;; object whose components are the types in TYPES, or skip to special
 ;;; cases when TYPES is short.
 ;;; shared logic for unions and intersections: Make a COMPOUND-TYPE
 ;;; object whose components are the types in TYPES, or skip to special
 ;;; cases when TYPES is short.

-(defun make-compound-type-or-something (constructor types enumerable identity)
+(defun make-probably-compound-type (constructor types enumerable identity)

   (declare (type function constructor))
   (declare (type (vector ctype) types))
   (declare (type ctype identity))
   (declare (type function constructor))
   (declare (type (vector ctype) types))
   (declare (type ctype identity))

@@ -829,14 +895,29 @@
                ;; brain-dead, so that would generate a full call to
                ;; SPECIFIER-TYPE at runtime, so we get into bootstrap
                ;; problems in cold init because 'LIST is a compound
                ;; brain-dead, so that would generate a full call to
                ;; SPECIFIER-TYPE at runtime, so we get into bootstrap
                ;; problems in cold init because 'LIST is a compound

-               ;; type, so we need to MAKE-COMPOUND-TYPE-OR-SOMETHING
+               ;; type, so we need to MAKE-PROBABLY-COMPOUND-TYPE

                ;; before we know what 'LIST is. Once the COERCE
                ;; optimizer is less brain-dead, we can make this
                ;; (COERCE TYPES 'LIST) again.
                #+sb-xc-host (coerce types 'list)
                #-sb-xc-host (coerce-to-list types)))))
 
                ;; before we know what 'LIST is. Once the COERCE
                ;; optimizer is less brain-dead, we can make this
                ;; (COERCE TYPES 'LIST) again.
                #+sb-xc-host (coerce types 'list)
                #-sb-xc-host (coerce-to-list types)))))
 

+(defun maybe-distribute-one-union (union-type types)
+  (let* ((intersection (apply #'type-intersection types))
+        (union (mapcar (lambda (x) (type-intersection x intersection))
+                       (union-type-types union-type))))
+    (if (notany (lambda (x) (or (hairy-type-p x)
+                               (intersection-type-p x)))
+               union)
+       union
+       nil)))
+

 (defun type-intersection (&rest input-types)
 (defun type-intersection (&rest input-types)

+  (%type-intersection input-types))
+(defun-cached (%type-intersection :hash-bits 8
+                                  :hash-function (lambda (x)
+                                                   (logand (sxhash x) #xff)))
+    ((input-types equal))

   (let ((simplified-types (simplified-compound-types input-types
                                                     #'intersection-type-p
                                                     #'type-intersection2)))
   (let ((simplified-types (simplified-compound-types input-types
                                                     #'intersection-type-p
                                                     #'type-intersection2)))

@@ -847,25 +928,40 @@
     ;; always achieve that by the distributive rule. But we don't want
     ;; to just apply the distributive rule, since it would be too easy
     ;; to end up with unreasonably huge type expressions. So instead
     ;; always achieve that by the distributive rule. But we don't want
     ;; to just apply the distributive rule, since it would be too easy
     ;; to end up with unreasonably huge type expressions. So instead

-    ;; we punt to HAIRY-TYPE when this comes up.
+    ;; we try to generate a simple type by distributing the union; if
+    ;; the type can't be made simple, we punt to HAIRY-TYPE.

     (if (and (> (length simplified-types) 1)
             (some #'union-type-p simplified-types))
     (if (and (> (length simplified-types) 1)
             (some #'union-type-p simplified-types))

-       (make-hairy-type
-        :specifier `(and ,@(map 'list #'type-specifier simplified-types)))
-       (make-compound-type-or-something #'%make-intersection-type
-                                        simplified-types
-                                        (some #'type-enumerable
-                                              simplified-types)
-                                        *universal-type*))))
+       (let* ((first-union (find-if #'union-type-p simplified-types))
+              (other-types (coerce (remove first-union simplified-types)
+                                   'list))
+              (distributed (maybe-distribute-one-union first-union
+                                                       other-types)))
+         (if distributed
+             (apply #'type-union distributed)
+             (make-hairy-type
+              :specifier `(and ,@(map 'list
+                                      #'type-specifier
+                                      simplified-types)))))
+       (make-probably-compound-type #'%make-intersection-type
+                                    simplified-types
+                                    (some #'type-enumerable
+                                          simplified-types)
+                                    *universal-type*))))

 
 (defun type-union (&rest input-types)
 
 (defun type-union (&rest input-types)

+  (%type-union input-types))
+(defun-cached (%type-union :hash-bits 8
+                           :hash-function (lambda (x)
+                                            (logand (sxhash x) #xff)))
+    ((input-types equal))

   (let ((simplified-types (simplified-compound-types input-types
                                                     #'union-type-p
                                                     #'type-union2)))
   (let ((simplified-types (simplified-compound-types input-types
                                                     #'union-type-p
                                                     #'type-union2)))

-    (make-compound-type-or-something #'%make-union-type
-                                    simplified-types
-                                    (every #'type-enumerable simplified-types)
-                                    *empty-type*)))
+    (make-probably-compound-type #'make-union-type
+                                simplified-types
+                                (every #'type-enumerable simplified-types)
+                                *empty-type*)))

 \f
 ;;;; built-in types
 
 \f
 ;;;; built-in types
 

@@ -879,7 +975,8 @@
  (macrolet ((frob (name var)
              `(progn
                 (setq ,var (make-named-type :name ',name))
  (macrolet ((frob (name var)
              `(progn
                 (setq ,var (make-named-type :name ',name))

-                (setf (info :type :kind ',name) :primitive)
+                (setf (info :type :kind ',name)
+                      #+sb-xc-host :defined #-sb-xc-host :primitive)

                 (setf (info :type :builtin ',name) ,var))))
    ;; KLUDGE: In ANSI, * isn't really the name of a type, it's just a
    ;; special symbol which can be stuck in some places where an
                 (setf (info :type :builtin ',name) ,var))))
    ;; KLUDGE: In ANSI, * isn't really the name of a type, it's just a
    ;; special symbol which can be stuck in some places where an

@@ -892,7 +989,7 @@
    (frob t *universal-type*))
  (setf *universal-fun-type*
        (make-fun-type :wild-args t
    (frob t *universal-type*))
  (setf *universal-fun-type*
        (make-fun-type :wild-args t

-                          :returns *wild-type*)))
+                     :returns *wild-type*)))

 
 (!define-type-method (named :simple-=) (type1 type2)
   ;; FIXME: BUG 85: This assertion failed when I added it in
 
 (!define-type-method (named :simple-=) (type1 type2)
   ;; FIXME: BUG 85: This assertion failed when I added it in

@@ -901,34 +998,72 @@
   ;;(aver (not (eq type1 *wild-type*))) ; * isn't really a type.
   (values (eq type1 type2) t))
 
   ;;(aver (not (eq type1 *wild-type*))) ; * isn't really a type.
   (values (eq type1 type2) t))
 

+(!define-type-method (named :complex-=) (type1 type2)
+  (cond
+    ((and (eq type2 *empty-type*)
+         (intersection-type-p type1)
+         ;; not allowed to be unsure on these... FIXME: keep the list
+         ;; of CL types that are intersection types once and only
+         ;; once.
+         (not (or (type= type1 (specifier-type 'ratio))
+                  (type= type1 (specifier-type 'keyword)))))
+     ;; things like (AND (EQL 0) (SATISFIES ODDP)) or (AND FUNCTION
+     ;; STREAM) can get here.  In general, we can't really tell
+     ;; whether these are equal to NIL or not, so
+     (values nil nil))
+    ((type-might-contain-other-types-p type1)
+     (invoke-complex-=-other-method type1 type2))
+    (t (values nil t))))
+

 (!define-type-method (named :simple-subtypep) (type1 type2)
   (aver (not (eq type1 *wild-type*))) ; * isn't really a type.
   (values (or (eq type1 *empty-type*) (eq type2 *wild-type*)) t))
 
 (!define-type-method (named :complex-subtypep-arg1) (type1 type2)
 (!define-type-method (named :simple-subtypep) (type1 type2)
   (aver (not (eq type1 *wild-type*))) ; * isn't really a type.
   (values (or (eq type1 *empty-type*) (eq type2 *wild-type*)) t))
 
 (!define-type-method (named :complex-subtypep-arg1) (type1 type2)

-  (aver (not (eq type1 *wild-type*))) ; * isn't really a type.
-  ;; FIXME: Why does this (old CMU CL) assertion hold? Perhaps 'cause
-  ;; the HAIRY-TYPE COMPLEX-SUBTYPEP-ARG2 method takes precedence over
-  ;; this COMPLEX-SUBTYPE-ARG1 method? (I miss CLOS..)
-  (aver (not (hairy-type-p type2))) 
-  ;; Besides the old CMU CL assertion above, we also need to avoid
-  ;; compound types, else we could get into trouble with
-  ;;   (SUBTYPEP T '(OR (SATISFIES FOO) (SATISFIES BAR)))
-  ;; or
-  ;;   (SUBTYPEP T '(AND (SATISFIES FOO) (SATISFIES BAR))).
-  (aver (not (compound-type-p type2))) 
-  ;; Then, since TYPE2 is reasonably tractable, we're good to go.
-  (values (eq type1 *empty-type*) t))
+  ;; This AVER causes problems if we write accurate methods for the
+  ;; union (and possibly intersection) types which then delegate to
+  ;; us; while a user shouldn't get here, because of the odd status of
+  ;; *wild-type* a type-intersection executed by the compiler can. -
+  ;; CSR, 2002-04-10
+  ;;
+  ;; (aver (not (eq type1 *wild-type*))) ; * isn't really a type.
+  (cond ((eq type1 *empty-type*)
+        t)
+       (;; When TYPE2 might be the universal type in disguise
+        (type-might-contain-other-types-p type2)
+        ;; Now that the UNION and HAIRY COMPLEX-SUBTYPEP-ARG2 methods
+        ;; can delegate to us (more or less as CALL-NEXT-METHOD) when
+        ;; they're uncertain, we can't just barf on COMPOUND-TYPE and
+        ;; HAIRY-TYPEs as we used to. Instead we deal with the
+        ;; problem (where at least part of the problem is cases like
+        ;;   (SUBTYPEP T '(SATISFIES FOO))
+        ;; or
+        ;;   (SUBTYPEP T '(AND (SATISFIES FOO) (SATISFIES BAR)))
+        ;; where the second type is a hairy type like SATISFIES, or
+        ;; is a compound type which might contain a hairy type) by
+        ;; returning uncertainty.
+        (values nil nil))
+       (t
+        ;; By elimination, TYPE1 is the universal type.
+        (aver (or (eq type1 *wild-type*) (eq type1 *universal-type*)))
+        ;; This case would have been picked off by the SIMPLE-SUBTYPEP
+        ;; method, and so shouldn't appear here.
+        (aver (not (eq type2 *universal-type*)))
+        ;; Since TYPE2 is not EQ *UNIVERSAL-TYPE* and is not the
+        ;; universal type in disguise, TYPE2 is not a superset of TYPE1.
+        (values nil t))))

 
 (!define-type-method (named :complex-subtypep-arg2) (type1 type2)
   (aver (not (eq type2 *wild-type*))) ; * isn't really a type.
   (cond ((eq type2 *universal-type*)
         (values t t))
 
 (!define-type-method (named :complex-subtypep-arg2) (type1 type2)
   (aver (not (eq type2 *wild-type*))) ; * isn't really a type.
   (cond ((eq type2 *universal-type*)
         (values t t))

-       ((hairy-type-p type1)
-        (values nil nil))
+       ((type-might-contain-other-types-p type1)
+        ;; those types can be *EMPTY-TYPE* or *UNIVERSAL-TYPE* in
+        ;; disguise.  So we'd better delegate.
+        (invoke-complex-subtypep-arg1-method type1 type2))

        (t
         ;; FIXME: This seems to rely on there only being 2 or 3
        (t
         ;; FIXME: This seems to rely on there only being 2 or 3

-        ;; HAIRY-TYPE values, and the exclusion of various
+        ;; NAMED-TYPE values, and the exclusion of various

         ;; possibilities above. It would be good to explain it and/or
         ;; rewrite it so that it's clearer.
         (values (not (eq type2 *empty-type*)) t))))
         ;; possibilities above. It would be good to explain it and/or
         ;; rewrite it so that it's clearer.
         (values (not (eq type2 *empty-type*)) t))))

@@ -949,56 +1084,46 @@
 \f
 ;;;; hairy and unknown types
 
 \f
 ;;;; hairy and unknown types
 

-(!define-type-method (hairy :unparse) (x) (hairy-type-specifier x))
-
+(!define-type-method (hairy :unparse) (x)
+  (hairy-type-specifier x))
+    

 (!define-type-method (hairy :simple-subtypep) (type1 type2)
   (let ((hairy-spec1 (hairy-type-specifier type1))
        (hairy-spec2 (hairy-type-specifier type2)))
 (!define-type-method (hairy :simple-subtypep) (type1 type2)
   (let ((hairy-spec1 (hairy-type-specifier type1))
        (hairy-spec2 (hairy-type-specifier type2)))

-    (cond ((and (consp hairy-spec1) (eq (car hairy-spec1) 'not)
-               (consp hairy-spec2) (eq (car hairy-spec2) 'not))
-          (csubtypep (specifier-type (cadr hairy-spec2))
-                     (specifier-type (cadr hairy-spec1))))
-         ((equal hairy-spec1 hairy-spec2)
+    (cond ((equal-but-no-car-recursion hairy-spec1 hairy-spec2)

           (values t t))
          (t
           (values nil nil)))))
 
 (!define-type-method (hairy :complex-subtypep-arg2) (type1 type2)
           (values t t))
          (t
           (values nil nil)))))
 
 (!define-type-method (hairy :complex-subtypep-arg2) (type1 type2)

-  (let ((hairy-spec (hairy-type-specifier type2)))
-    (cond ((and (consp hairy-spec) (eq (car hairy-spec) 'not))
-          (let* ((complement-type2 (specifier-type (cadr hairy-spec)))
-                 (intersection2 (type-intersection2 type1
-                                                    complement-type2)))
-            (if intersection2
-                (values (eq intersection2 *empty-type*) t)
-                (values nil nil))))
-         (t
-          (values nil nil)))))
+  (invoke-complex-subtypep-arg1-method type1 type2))

 
 

-(!define-type-method (hairy :complex-subtypep-arg1 :complex-=) (type1 type2)
+(!define-type-method (hairy :complex-subtypep-arg1) (type1 type2)

   (declare (ignore type1 type2))
   (values nil nil))
 
   (declare (ignore type1 type2))
   (values nil nil))
 

-(!define-type-method (hairy :simple-intersection2 :complex-intersection2)
-                    (type1 type2)
+(!define-type-method (hairy :complex-=) (type1 type2)

   (declare (ignore type1 type2))
   (declare (ignore type1 type2))

-  nil)
+  (values nil nil))
+
+(!define-type-method (hairy :simple-intersection2 :complex-intersection2) 
+                    (type1 type2)
+  (if (type= type1 type2)
+      type1
+      nil))
+
+(!define-type-method (hairy :simple-union2) 
+                    (type1 type2)
+  (if (type= type1 type2)
+      type1
+      nil))

 
 (!define-type-method (hairy :simple-=) (type1 type2)
 
 (!define-type-method (hairy :simple-=) (type1 type2)

-  (if (equal (hairy-type-specifier type1)
-            (hairy-type-specifier type2))
+  (if (equal-but-no-car-recursion (hairy-type-specifier type1)
+                                 (hairy-type-specifier type2))

       (values t t)
       (values nil nil)))
 
       (values t t)
       (values nil nil)))
 

-(!def-type-translator not (&whole whole type)
-  (declare (ignore type))
-  ;; Check legality of arguments.
-  (destructuring-bind (not typespec) whole
-    (declare (ignore not))
-    (specifier-type typespec)) ; must be legal typespec
-  ;; Create object.
-  (make-hairy-type :specifier whole))
-

 (!def-type-translator satisfies (&whole whole fun)
   (declare (ignore fun))
   ;; Check legality of arguments.
 (!def-type-translator satisfies (&whole whole fun)
   (declare (ignore fun))
   ;; Check legality of arguments.

@@ -1008,11 +1133,281 @@
       (error 'simple-type-error
             :datum predicate-name
             :expected-type 'symbol
       (error 'simple-type-error
             :datum predicate-name
             :expected-type 'symbol

-            :format-control "~S is not a symbol."
+            :format-control "The SATISFIES predicate name is not a symbol: ~S"

             :format-arguments (list predicate-name))))
   ;; Create object.
   (make-hairy-type :specifier whole))
 \f
             :format-arguments (list predicate-name))))
   ;; Create object.
   (make-hairy-type :specifier whole))
 \f

+;;;; negation types
+
+(!define-type-method (negation :unparse) (x)
+  `(not ,(type-specifier (negation-type-type x))))
+
+(!define-type-method (negation :simple-subtypep) (type1 type2)
+  (csubtypep (negation-type-type type2) (negation-type-type type1)))
+
+(!define-type-method (negation :complex-subtypep-arg2) (type1 type2)
+  (let* ((complement-type2 (negation-type-type type2))
+        (intersection2 (type-intersection2 type1
+                                           complement-type2)))
+    (if intersection2
+       ;; FIXME: if uncertain, maybe try arg1?
+       (type= intersection2 *empty-type*)
+       (invoke-complex-subtypep-arg1-method type1 type2))))
+
+(!define-type-method (negation :complex-subtypep-arg1) (type1 type2)
+  ;; "Incrementally extended heuristic algorithms tend inexorably toward the
+  ;; incomprehensible." -- http://www.unlambda.com/~james/lambda/lambda.txt
+  ;;
+  ;; You may not believe this. I couldn't either. But then I sat down
+  ;; and drew lots of Venn diagrams. Comments involving a and b refer
+  ;; to the call (subtypep '(not a) 'b) -- CSR, 2002-02-27.
+  (block nil
+    ;; (Several logical truths in this block are true as long as
+    ;; b/=T. As of sbcl-0.7.1.28, it seems impossible to construct a
+    ;; case with b=T where we actually reach this type method, but
+    ;; we'll test for and exclude this case anyway, since future
+    ;; maintenance might make it possible for it to end up in this
+    ;; code.)
+    (multiple-value-bind (equal certain)
+       (type= type2 *universal-type*)
+      (unless certain
+       (return (values nil nil)))
+      (when equal
+       (return (values t t))))
+    (let ((complement-type1 (negation-type-type type1)))
+      ;; Do the special cases first, in order to give us a chance if
+      ;; subtype/supertype relationships are hairy.
+      (multiple-value-bind (equal certain) 
+         (type= complement-type1 type2)
+       ;; If a = b, ~a is not a subtype of b (unless b=T, which was
+       ;; excluded above).
+       (unless certain
+         (return (values nil nil)))
+       (when equal
+         (return (values nil t))))
+      ;; KLUDGE: ANSI requires that the SUBTYPEP result between any
+      ;; two built-in atomic type specifiers never be uncertain. This
+      ;; is hard to do cleanly for the built-in types whose
+      ;; definitions include (NOT FOO), i.e. CONS and RATIO. However,
+      ;; we can do it with this hack, which uses our global knowledge
+      ;; that our implementation of the type system uses disjoint
+      ;; implementation types to represent disjoint sets (except when
+      ;; types are contained in other types).  (This is a KLUDGE
+      ;; because it's fragile. Various changes in internal
+      ;; representation in the type system could make it start
+      ;; confidently returning incorrect results.) -- WHN 2002-03-08
+      (unless (or (type-might-contain-other-types-p complement-type1)
+                 (type-might-contain-other-types-p type2))
+       ;; Because of the way our types which don't contain other
+       ;; types are disjoint subsets of the space of possible values,
+       ;; (SUBTYPEP '(NOT AA) 'B)=NIL when AA and B are simple (and B
+       ;; is not T, as checked above).
+       (return (values nil t)))
+      ;; The old (TYPE= TYPE1 TYPE2) branch would never be taken, as
+      ;; TYPE1 and TYPE2 will only be equal if they're both NOT types,
+      ;; and then the :SIMPLE-SUBTYPEP method would be used instead.
+      ;; But a CSUBTYPEP relationship might still hold:
+      (multiple-value-bind (equal certain)
+         (csubtypep complement-type1 type2)
+       ;; If a is a subtype of b, ~a is not a subtype of b (unless
+       ;; b=T, which was excluded above).
+       (unless certain
+         (return (values nil nil)))
+       (when equal
+         (return (values nil t))))
+      (multiple-value-bind (equal certain)
+         (csubtypep type2 complement-type1)
+       ;; If b is a subtype of a, ~a is not a subtype of b.  (FIXME:
+       ;; That's not true if a=T. Do we know at this point that a is
+       ;; not T?)
+       (unless certain
+         (return (values nil nil)))
+       (when equal
+         (return (values nil t))))
+      ;; old CSR comment ca. 0.7.2, now obsoleted by the SIMPLE-CTYPE?
+      ;; KLUDGE case above: Other cases here would rely on being able
+      ;; to catch all possible cases, which the fragility of this type
+      ;; system doesn't inspire me; for instance, if a is type= to ~b,
+      ;; then we want T, T; if this is not the case and the types are
+      ;; disjoint (have an intersection of *empty-type*) then we want
+      ;; NIL, T; else if the union of a and b is the *universal-type*
+      ;; then we want T, T. So currently we still claim to be unsure
+      ;; about e.g. (subtypep '(not fixnum) 'single-float).
+      ;;
+      ;; OTOH we might still get here:
+      (values nil nil))))
+
+(!define-type-method (negation :complex-=) (type1 type2)
+  ;; (NOT FOO) isn't equivalent to anything that's not a negation
+  ;; type, except possibly a type that might contain it in disguise.
+  (declare (ignore type2))
+  (if (type-might-contain-other-types-p type1)
+      (values nil nil)
+      (values nil t)))
+
+(!define-type-method (negation :simple-intersection2) (type1 type2)
+  (let ((not1 (negation-type-type type1))
+       (not2 (negation-type-type type2)))
+    (cond
+      ((csubtypep not1 not2) type2)
+      ((csubtypep not2 not1) type1)
+      ;; Why no analagous clause to the disjoint in the SIMPLE-UNION2
+      ;; method, below?  The clause would read
+      ;;
+      ;; ((EQ (TYPE-UNION NOT1 NOT2) *UNIVERSAL-TYPE*) *EMPTY-TYPE*)
+      ;;
+      ;; but with proper canonicalization of negation types, there's
+      ;; no way of constructing two negation types with union of their
+      ;; negations being the universal type.
+      (t
+       (aver (not (eq (type-union not1 not2) *universal-type*)))
+       nil))))
+
+(!define-type-method (negation :complex-intersection2) (type1 type2)
+  (cond
+    ((csubtypep type1 (negation-type-type type2)) *empty-type*)
+    ((eq (type-intersection type1 (negation-type-type type2)) *empty-type*)
+     type1)
+    (t nil)))
+
+(!define-type-method (negation :simple-union2) (type1 type2)
+  (let ((not1 (negation-type-type type1))
+       (not2 (negation-type-type type2)))
+    (cond
+      ((csubtypep not1 not2) type1)
+      ((csubtypep not2 not1) type2)
+      ((eq (type-intersection not1 not2) *empty-type*)
+       *universal-type*)
+      (t nil))))
+
+(!define-type-method (negation :complex-union2) (type1 type2)
+  (cond
+    ((csubtypep (negation-type-type type2) type1) *universal-type*)
+    ((eq (type-intersection type1 (negation-type-type type2)) *empty-type*)
+     type2)
+    (t nil)))
+
+(!define-type-method (negation :simple-=) (type1 type2)
+  (type= (negation-type-type type1) (negation-type-type type2)))
+
+(!def-type-translator not (typespec)
+  (let* ((not-type (specifier-type typespec))
+        (spec (type-specifier not-type)))
+    (cond
+      ;; canonicalize (NOT (NOT FOO))
+      ((and (listp spec) (eq (car spec) 'not))
+       (specifier-type (cadr spec)))
+      ;; canonicalize (NOT NIL) and (NOT T)
+      ((eq not-type *empty-type*) *universal-type*)
+      ((eq not-type *universal-type*) *empty-type*)
+      ((and (numeric-type-p not-type)
+           (null (numeric-type-low not-type))
+           (null (numeric-type-high not-type)))
+       (make-negation-type :type not-type))
+      ((numeric-type-p not-type)
+       (type-union
+       (make-negation-type
+        :type (modified-numeric-type not-type :low nil :high nil))
+       (cond
+         ((null (numeric-type-low not-type))
+          (modified-numeric-type
+           not-type
+           :low (let ((h (numeric-type-high not-type)))
+                  (if (consp h) (car h) (list h)))
+           :high nil))
+         ((null (numeric-type-high not-type))
+          (modified-numeric-type
+           not-type
+           :low nil
+           :high (let ((l (numeric-type-low not-type)))
+                   (if (consp l) (car l) (list l)))))
+         (t (type-union
+             (modified-numeric-type
+              not-type
+              :low nil
+              :high (let ((l (numeric-type-low not-type)))
+                      (if (consp l) (car l) (list l))))
+             (modified-numeric-type
+              not-type
+              :low (let ((h (numeric-type-high not-type)))
+                     (if (consp h) (car h) (list h)))
+              :high nil))))))
+      ((intersection-type-p not-type)
+       (apply #'type-union
+             (mapcar #'(lambda (x)
+                         (specifier-type `(not ,(type-specifier x))))
+                     (intersection-type-types not-type))))
+      ((union-type-p not-type)
+       (apply #'type-intersection
+             (mapcar #'(lambda (x)
+                         (specifier-type `(not ,(type-specifier x))))
+                     (union-type-types not-type))))
+      ((member-type-p not-type)
+       (let ((members (member-type-members not-type)))
+        (if (some #'floatp members)
+            (let (floats)
+              (dolist (pair '((0.0f0 . -0.0f0) (0.0d0 . -0.0d0)
+                              #!+long-float (0.0l0 . -0.0l0)))
+                (when (member (car pair) members)
+                  (aver (not (member (cdr pair) members)))
+                  (push (cdr pair) floats)
+                  (setf members (remove (car pair) members)))
+                (when (member (cdr pair) members)
+                  (aver (not (member (car pair) members)))
+                  (push (car pair) floats)
+                  (setf members (remove (cdr pair) members))))
+              (apply #'type-intersection
+                     (if (null members)
+                         *universal-type*
+                         (make-negation-type
+                          :type (make-member-type :members members)))
+                     (mapcar
+                      (lambda (x)
+                        (let ((type (ctype-of x)))
+                          (type-union
+                           (make-negation-type
+                            :type (modified-numeric-type type
+                                                         :low nil :high nil))
+                           (modified-numeric-type type
+                                                  :low nil :high (list x))
+                           (make-member-type :members (list x))
+                           (modified-numeric-type type
+                                                  :low (list x) :high nil))))
+                      floats)))
+            (make-negation-type :type not-type))))
+      ((and (cons-type-p not-type)
+           (eq (cons-type-car-type not-type) *universal-type*)
+           (eq (cons-type-cdr-type not-type) *universal-type*))
+       (make-negation-type :type not-type))
+      ((cons-type-p not-type)
+       (type-union
+       (make-negation-type :type (specifier-type 'cons))
+       (cond
+         ((and (not (eq (cons-type-car-type not-type) *universal-type*))
+               (not (eq (cons-type-cdr-type not-type) *universal-type*)))
+          (type-union
+           (make-cons-type
+            (specifier-type `(not ,(type-specifier
+                                    (cons-type-car-type not-type))))
+            *universal-type*)
+           (make-cons-type
+            *universal-type*
+            (specifier-type `(not ,(type-specifier
+                                    (cons-type-cdr-type not-type)))))))
+         ((not (eq (cons-type-car-type not-type) *universal-type*))
+          (make-cons-type
+           (specifier-type `(not ,(type-specifier
+                                   (cons-type-car-type not-type))))
+           *universal-type*))
+         ((not (eq (cons-type-cdr-type not-type) *universal-type*))
+          (make-cons-type
+           *universal-type*
+           (specifier-type `(not ,(type-specifier
+                                   (cons-type-cdr-type not-type))))))
+         (t (bug "Weird CONS type ~S" not-type)))))
+      (t (make-negation-type :type not-type)))))
+\f

 ;;;; numeric types
 
 (!define-type-class number)
 ;;;; numeric types
 
 (!define-type-class number)

@@ -1047,8 +1442,8 @@
                                  `(unsigned-byte ,high-length))
                                 (t
                                  `(mod ,(1+ high)))))
                                  `(unsigned-byte ,high-length))
                                 (t
                                  `(mod ,(1+ high)))))

-                         ((and (= low sb!vm:*target-most-negative-fixnum*)
-                               (= high sb!vm:*target-most-positive-fixnum*))
+                         ((and (= low sb!xc:most-negative-fixnum)
+                               (= high sb!xc:most-positive-fixnum))

                           'fixnum)
                          ((and (= low (lognot high))
                                (= high-count high-length)
                           'fixnum)
                          ((and (= low (lognot high))
                                (= high-count high-length)

@@ -1180,11 +1575,13 @@
                    (null complexp2)))
           (values nil t))
          ;; If the classes are specified and different, the types are
                    (null complexp2)))
           (values nil t))
          ;; If the classes are specified and different, the types are

-         ;; disjoint unless type2 is rational and type1 is integer.
+         ;; disjoint unless type2 is RATIONAL and type1 is INTEGER.
+         ;; [ or type1 is INTEGER and type2 is of the form (RATIONAL
+         ;; X X) for integral X, but this is dealt with in the
+         ;; canonicalization inside MAKE-NUMERIC-TYPE ]

          ((not (or (eq class1 class2)
                    (null class2)
          ((not (or (eq class1 class2)
                    (null class2)

-                   (and (eq class1 'integer)
-                        (eq class2 'rational))))
+                   (and (eq class1 'integer) (eq class2 'rational))))

           (values nil t))
          ;; If the float formats are specified and different, the types
          ;; are disjoint.
           (values nil t))
          ;; If the float formats are specified and different, the types
          ;; are disjoint.

@@ -1198,7 +1595,7 @@
          (t
           (values nil t)))))
 
          (t
           (values nil t)))))
 

-(!define-superclasses number ((generic-number)) !cold-init-forms)
+(!define-superclasses number ((number)) !cold-init-forms)

 
 ;;; If the high bound of LOW is adjacent to the low bound of HIGH,
 ;;; then return true, otherwise NIL.
 
 ;;; If the high bound of LOW is adjacent to the low bound of HIGH,
 ;;; then return true, otherwise NIL.

@@ -1238,8 +1635,10 @@
 
 ;;; Return a numeric type that is a supertype for both TYPE1 and TYPE2.
 ;;;
 
 ;;; Return a numeric type that is a supertype for both TYPE1 and TYPE2.
 ;;;

-;;; ### Note: we give up early to keep from dropping lots of information on
-;;; the floor by returning overly general types.
+;;; Old comment, probably no longer applicable:
+;;;
+;;;   ### Note: we give up early to keep from dropping lots of
+;;;   information on the floor by returning overly general types.

 (!define-type-method (number :simple-union2) (type1 type2)
   (declare (type numeric-type type1 type2))
   (cond ((csubtypep type1 type2) type2)
 (!define-type-method (number :simple-union2) (type1 type2)
   (declare (type numeric-type type1 type2))
   (cond ((csubtypep type1 type2) type2)

@@ -1251,25 +1650,69 @@
               (class2 (numeric-type-class type2))
               (format2 (numeric-type-format type2))
               (complexp2 (numeric-type-complexp type2)))
               (class2 (numeric-type-class type2))
               (format2 (numeric-type-format type2))
               (complexp2 (numeric-type-complexp type2)))

-          (when (and (eq class1 class2)
-                     (eq format1 format2)
-                     (eq complexp1 complexp2)
-                     (or (numeric-types-intersect type1 type2)
-                         (numeric-types-adjacent type1 type2)
-                         (numeric-types-adjacent type2 type1)))
-            (make-numeric-type
-             :class class1
-             :format format1
-             :complexp complexp1
-             :low (numeric-bound-max (numeric-type-low type1)
-                                     (numeric-type-low type2)
-                                     <= < t)
-             :high (numeric-bound-max (numeric-type-high type1)
-                                      (numeric-type-high type2)
-                                      >= > t)))))))
+          (cond
+            ((and (eq class1 class2)
+                  (eq format1 format2)
+                  (eq complexp1 complexp2)
+                  (or (numeric-types-intersect type1 type2)
+                      (numeric-types-adjacent type1 type2)
+                      (numeric-types-adjacent type2 type1)))
+             (make-numeric-type
+              :class class1
+              :format format1
+              :complexp complexp1
+              :low (numeric-bound-max (numeric-type-low type1)
+                                      (numeric-type-low type2)
+                                      <= < t)
+              :high (numeric-bound-max (numeric-type-high type1)
+                                       (numeric-type-high type2)
+                                       >= > t)))
+            ;; FIXME: These two clauses are almost identical, and the
+            ;; consequents are in fact identical in every respect.
+            ((and (eq class1 'rational)
+                  (eq class2 'integer)
+                  (eq format1 format2)
+                  (eq complexp1 complexp2)
+                  (integerp (numeric-type-low type2))
+                  (integerp (numeric-type-high type2))
+                  (= (numeric-type-low type2) (numeric-type-high type2))
+                  (or (numeric-types-adjacent type1 type2)
+                      (numeric-types-adjacent type2 type1)))
+             (make-numeric-type
+              :class 'rational
+              :format format1
+              :complexp complexp1
+              :low (numeric-bound-max (numeric-type-low type1)
+                                      (numeric-type-low type2)
+                                      <= < t)
+              :high (numeric-bound-max (numeric-type-high type1)
+                                       (numeric-type-high type2)
+                                       >= > t)))
+            ((and (eq class1 'integer)
+                  (eq class2 'rational)
+                  (eq format1 format2)
+                  (eq complexp1 complexp2)
+                  (integerp (numeric-type-low type1))
+                  (integerp (numeric-type-high type1))
+                  (= (numeric-type-low type1) (numeric-type-high type1))
+                  (or (numeric-types-adjacent type1 type2)
+                      (numeric-types-adjacent type2 type1)))
+             (make-numeric-type
+              :class 'rational
+              :format format1
+              :complexp complexp1
+              :low (numeric-bound-max (numeric-type-low type1)
+                                      (numeric-type-low type2)
+                                      <= < t)
+              :high (numeric-bound-max (numeric-type-high type1)
+                                       (numeric-type-high type2)
+                                       >= > t)))
+            (t nil))))))
+             

 
 (!cold-init-forms
 
 (!cold-init-forms

-  (setf (info :type :kind 'number) :primitive)
+  (setf (info :type :kind 'number)
+       #+sb-xc-host :defined #-sb-xc-host :primitive)

   (setf (info :type :builtin 'number)
        (make-numeric-type :complexp nil)))
 
   (setf (info :type :builtin 'number)
        (make-numeric-type :complexp nil)))
 

@@ -1277,34 +1720,80 @@
   (if (eq typespec '*)
       (make-numeric-type :complexp :complex)
       (labels ((not-numeric ()
   (if (eq typespec '*)
       (make-numeric-type :complexp :complex)
       (labels ((not-numeric ()

-                 ;; FIXME: should probably be TYPE-ERROR

                 (error "The component type for COMPLEX is not numeric: ~S"
                        typespec))
                 (error "The component type for COMPLEX is not numeric: ~S"
                        typespec))

+              (not-real ()
+                (error "The component type for COMPLEX is not real: ~S"
+                       typespec))

               (complex1 (component-type)
                 (unless (numeric-type-p component-type)
               (complex1 (component-type)
                 (unless (numeric-type-p component-type)

-                  ;; FIXME: As per the FIXME below, ANSI says we're
-                  ;; supposed to handle any subtype of REAL, not only
-                  ;; those which can be represented as NUMERIC-TYPE.

                   (not-numeric))
                 (when (eq (numeric-type-complexp component-type) :complex)
                   (not-numeric))
                 (when (eq (numeric-type-complexp component-type) :complex)

-                  (error "The component type for COMPLEX is complex: ~S"
-                         typespec))
-                (modified-numeric-type component-type :complexp :complex)))
-       (let ((type (specifier-type typespec)))
-         (typecase type
-           ;; This is all that CMU CL handled.
-           (numeric-type (complex1 type))
-           ;; We need to handle UNION-TYPEs in order to deal with
-           ;; REAL and FLOAT being represented as UNION-TYPEs of more
-           ;; primitive types.
+                  (not-real))
+                (modified-numeric-type component-type :complexp :complex))
+              (complex-union (component)
+                (unless (numberp component)
+                  (not-numeric))
+                ;; KLUDGE: This TYPECASE more or less does
+                ;; (UPGRADED-COMPLEX-PART-TYPE (TYPE-OF COMPONENT)),
+                ;; (plus a small hack to treat (EQL COMPONENT 0) specially)
+                ;; but uses logic cut and pasted from the DEFUN of
+                ;; UPGRADED-COMPLEX-PART-TYPE. That's fragile, because
+                ;; changing the definition of UPGRADED-COMPLEX-PART-TYPE
+                ;; would tend to break the code here. Unfortunately,
+                ;; though, reusing UPGRADED-COMPLEX-PART-TYPE here
+                ;; would cause another kind of fragility, because
+                ;; ANSI's definition of TYPE-OF is so weak that e.g.
+                ;; (UPGRADED-COMPLEX-PART-TYPE (TYPE-OF 1/2)) could
+                ;; end up being (UPGRADED-COMPLEX-PART-TYPE 'REAL)
+                ;; instead of (UPGRADED-COMPLEX-PART-TYPE 'RATIONAL).
+                ;; So using TYPE-OF would mean that ANSI-conforming
+                ;; maintenance changes in TYPE-OF could break the code here.
+                ;; It's not clear how best to fix this. -- WHN 2002-01-21,
+                ;; trying to summarize CSR's concerns in his patch
+                (typecase component
+                  (complex (error "The component type for COMPLEX (EQL X) ~
+                                    is complex: ~S"
+                                  component))
+                  ((eql 0) (specifier-type nil)) ; as required by ANSI
+                  (single-float (specifier-type '(complex single-float)))
+                  (double-float (specifier-type '(complex double-float)))
+                  #!+long-float
+                  (long-float (specifier-type '(complex long-float)))
+                  (rational (specifier-type '(complex rational)))
+                  (t (specifier-type '(complex real))))))
+       (let ((ctype (specifier-type typespec)))
+         (typecase ctype
+           (numeric-type (complex1 ctype))

            (union-type (apply #'type-union
            (union-type (apply #'type-union

+                              ;; FIXME: This code could suffer from
+                              ;; (admittedly very obscure) cases of
+                              ;; bug 145 e.g. when TYPE is
+                              ;;   (OR (AND INTEGER (SATISFIES ODDP))
+                              ;;       (AND FLOAT (SATISFIES FOO))
+                              ;; and not even report the problem very well.

                               (mapcar #'complex1
                               (mapcar #'complex1

-                                      (union-type-types type))))
-           ;; FIXME: ANSI just says that TYPESPEC is a subtype of type
-           ;; REAL, not necessarily a NUMERIC-TYPE. E.g. TYPESPEC could
-           ;; legally be (AND REAL (SATISFIES ODDP))! But like the old
-           ;; CMU CL code, we're still not nearly that general.
-           (t (not-numeric)))))))
+                                      (union-type-types ctype))))
+           ;; MEMBER-TYPE is almost the same as UNION-TYPE, but
+           ;; there's a gotcha: (COMPLEX (EQL 0)) is, according to
+           ;; ANSI, equal to type NIL, the empty set.
+           (member-type (apply #'type-union
+                               (mapcar #'complex-union
+                                       (member-type-members ctype))))
+           (t
+            (multiple-value-bind (subtypep certainly)
+                (csubtypep ctype (specifier-type 'real))
+              (if (and (not subtypep) certainly)
+                  (not-real)
+                  ;; ANSI just says that TYPESPEC is any subtype of
+                  ;; type REAL, not necessarily a NUMERIC-TYPE. In
+                  ;; particular, at this point TYPESPEC could legally be
+                  ;; an intersection type like (AND REAL (SATISFIES ODDP)),
+                  ;; in which case we fall through the logic above and
+                  ;; end up here, stumped.
+                  (bug "~@<(known bug #145): The type ~S is too hairy to be 
+                         used for a COMPLEX component.~:@>"
+                       typespec)))))))))

 
 ;;; If X is *, return NIL, otherwise return the bound, which must be a
 ;;; member of TYPE or a one-element list of a member of TYPE.
 
 ;;; If X is *, return NIL, otherwise return the bound, which must be a
 ;;; member of TYPE or a one-element list of a member of TYPE.

@@ -1328,21 +1817,24 @@
         (lb (if (consp l) (1+ (car l)) l))
         (h (canonicalized-bound high 'integer))
         (hb (if (consp h) (1- (car h)) h)))
         (lb (if (consp l) (1+ (car l)) l))
         (h (canonicalized-bound high 'integer))
         (hb (if (consp h) (1- (car h)) h)))

-    (when (and hb lb (< hb lb))
-      (error "Lower bound ~S is greater than upper bound ~S." l h))
-    (make-numeric-type :class 'integer
-                      :complexp :real
-                      :enumerable (not (null (and l h)))
-                      :low lb
-                      :high hb)))
+    (if (and hb lb (< hb lb))
+       *empty-type*
+      (make-numeric-type :class 'integer
+                        :complexp :real
+                        :enumerable (not (null (and l h)))
+                        :low lb
+                        :high hb))))

 
 (defmacro !def-bounded-type (type class format)
   `(!def-type-translator ,type (&optional (low '*) (high '*))
      (let ((lb (canonicalized-bound low ',type))
           (hb (canonicalized-bound high ',type)))
 
 (defmacro !def-bounded-type (type class format)
   `(!def-type-translator ,type (&optional (low '*) (high '*))
      (let ((lb (canonicalized-bound low ',type))
           (hb (canonicalized-bound high ',type)))

-       (unless (numeric-bound-test* lb hb <= <)
-        (error "Lower bound ~S is not less than upper bound ~S." low high))
-       (make-numeric-type :class ',class :format ',format :low lb :high hb))))
+       (if (not (numeric-bound-test* lb hb <= <))
+          *empty-type*
+        (make-numeric-type :class ',class
+                           :format ',format
+                           :low lb
+                           :high hb)))))

 
 (!def-bounded-type rational rational nil)
 
 
 (!def-bounded-type rational rational nil)
 

@@ -1611,13 +2103,23 @@
       (array-type-element-type type)))
 
 (!define-type-method (array :simple-=) (type1 type2)
       (array-type-element-type type)))
 
 (!define-type-method (array :simple-=) (type1 type2)

-  (values (and (equal (array-type-dimensions type1)
-                     (array-type-dimensions type2))
-              (eq (array-type-complexp type1)
-                  (array-type-complexp type2))
-              (type= (specialized-element-type-maybe type1)
-                     (specialized-element-type-maybe type2)))
-         t))
+  (if (or (unknown-type-p (array-type-element-type type1))
+         (unknown-type-p (array-type-element-type type2)))
+      (multiple-value-bind (equalp certainp)
+         (type= (array-type-element-type type1)
+                (array-type-element-type type2))
+       ;; by its nature, the call to TYPE= should never return NIL,
+       ;; T, as we don't know what the UNKNOWN-TYPE will grow up to
+       ;; be.  -- CSR, 2002-08-19
+       (aver (not (and (not equalp) certainp)))
+       (values equalp certainp))
+      (values (and (equal (array-type-dimensions type1)
+                         (array-type-dimensions type2))
+                  (eq (array-type-complexp type1)
+                      (array-type-complexp type2))
+                  (type= (specialized-element-type-maybe type1)
+                         (specialized-element-type-maybe type2)))
+             t)))

 
 (!define-type-method (array :unparse) (type)
   (let ((dims (array-type-dimensions type))
 
 (!define-type-method (array :unparse) (type)
   (let ((dims (array-type-dimensions type))

@@ -1723,10 +2225,28 @@
                    (eq complexp2 :maybe)
                    (eq complexp1 complexp2)))
           (values nil t))
                    (eq complexp2 :maybe)
                    (eq complexp1 complexp2)))
           (values nil t))

-         ;; If either element type is wild, then they intersect.
-         ;; Otherwise, the types must be identical.
-         ((or (eq (array-type-element-type type1) *wild-type*)
-              (eq (array-type-element-type type2) *wild-type*)
+         ;; Old comment:
+         ;;
+         ;;   If either element type is wild, then they intersect.
+         ;;   Otherwise, the types must be identical.
+         ;;
+         ;; FIXME: There seems to have been a fair amount of
+         ;; confusion about the distinction between requested element
+         ;; type and specialized element type; here is one of
+         ;; them. If we request an array to hold objects of an
+         ;; unknown type, we can do no better than represent that
+         ;; type as an array specialized on wild-type.  We keep the
+         ;; requested element-type in the -ELEMENT-TYPE slot, and
+         ;; *WILD-TYPE* in the -SPECIALIZED-ELEMENT-TYPE.  So, here,
+         ;; we must test for the SPECIALIZED slot being *WILD-TYPE*,
+         ;; not just the ELEMENT-TYPE slot.  Maybe the return value
+         ;; in that specific case should be T, NIL?  Or maybe this
+         ;; function should really be called
+         ;; ARRAY-TYPES-COULD-POSSIBLY-INTERSECT?  In any case, this
+         ;; was responsible for bug #123, and this whole issue could
+         ;; do with a rethink and/or a rewrite.  -- CSR, 2002-08-21
+         ((or (eq (array-type-specialized-element-type type1) *wild-type*)
+              (eq (array-type-specialized-element-type type2) *wild-type*)

               (type= (specialized-element-type-maybe type1)
                      (specialized-element-type-maybe type2)))
 
               (type= (specialized-element-type-maybe type1)
                      (specialized-element-type-maybe type2)))
 

@@ -1784,9 +2304,10 @@
 
 (!define-type-method (member :unparse) (type)
   (let ((members (member-type-members type)))
 
 (!define-type-method (member :unparse) (type)
   (let ((members (member-type-members type)))

-    (if (equal members '(nil))
-       'null
-       `(member ,@members))))
+    (cond
+      ((equal members '(nil)) 'null)
+      ((type= type (specifier-type 'standard-char)) 'standard-char)
+      (t `(member ,@members)))))

 
 (!define-type-method (member :simple-subtypep) (type1 type2)
   (values (subsetp (member-type-members type1) (member-type-members type2))
 
 (!define-type-method (member :simple-subtypep) (type1 type2)
   (values (subsetp (member-type-members type1) (member-type-members type2))

@@ -1802,7 +2323,8 @@
 ;;; subtype of the MEMBER type.
 (!define-type-method (member :complex-subtypep-arg2) (type1 type2)
   (cond ((not (type-enumerable type1)) (values nil t))
 ;;; subtype of the MEMBER type.
 (!define-type-method (member :complex-subtypep-arg2) (type1 type2)
   (cond ((not (type-enumerable type1)) (values nil t))

-       ((types-equal-or-intersect type1 type2) (values nil nil))
+       ((types-equal-or-intersect type1 type2)
+        (invoke-complex-subtypep-arg1-method type1 type2))

        (t (values nil t))))
 
 (!define-type-method (member :simple-intersection2) (type1 type2)
        (t (values nil t))))
 
 (!define-type-method (member :simple-intersection2) (type1 type2)

@@ -1817,7 +2339,7 @@
                 *empty-type*))))))
 
 (!define-type-method (member :complex-intersection2) (type1 type2)
                 *empty-type*))))))
 
 (!define-type-method (member :complex-intersection2) (type1 type2)

-  (block punt               
+  (block punt

     (collect ((members))
       (let ((mem2 (member-type-members type2)))
         (dolist (member mem2)
     (collect ((members))
       (let ((mem2 (member-type-members type2)))
         (dolist (member mem2)

@@ -1858,8 +2380,21 @@
 
 (!def-type-translator member (&rest members)
   (if members
 
 (!def-type-translator member (&rest members)
   (if members

-    (make-member-type :members (remove-duplicates members))
-    *empty-type*))
+      (let (ms numbers)
+       (dolist (m (remove-duplicates members))
+         (typecase m
+           #!-negative-zero-is-not-zero
+           (float (if (zerop m)
+                      (push m ms)
+                      (push (ctype-of m) numbers)))
+           (number (push (ctype-of m) numbers))
+           (t (push m ms))))
+       (apply #'type-union
+              (if ms
+                  (make-member-type :members ms)
+                  *empty-type*)
+              (nreverse numbers)))
+      *empty-type*))

 \f
 ;;;; intersection types
 ;;;;
 \f
 ;;;; intersection types
 ;;;;

@@ -1886,21 +2421,19 @@
 ;;; mechanically unparsed.
 (!define-type-method (intersection :unparse) (type)
   (declare (type ctype type))
 ;;; mechanically unparsed.
 (!define-type-method (intersection :unparse) (type)
   (declare (type ctype type))

-  (or (find type '(ratio bignum keyword) :key #'specifier-type :test #'type=)
+  (or (find type '(ratio keyword) :key #'specifier-type :test #'type=)

       `(and ,@(mapcar #'type-specifier (intersection-type-types type)))))
 
 ;;; shared machinery for type equality: true if every type in the set
 ;;; TYPES1 matches a type in the set TYPES2 and vice versa
 (defun type=-set (types1 types2)
       `(and ,@(mapcar #'type-specifier (intersection-type-types type)))))
 
 ;;; shared machinery for type equality: true if every type in the set
 ;;; TYPES1 matches a type in the set TYPES2 and vice versa
 (defun type=-set (types1 types2)

-  (flet (;; true if every type in the set X matches a type in the set Y
-        (type<=-set (x y)
+  (flet ((type<=-set (x y)

           (declare (type list x y))
           (declare (type list x y))

-          (every (lambda (xelement)
-                   (position xelement y :test #'type=))
-                 x)))
-    (values (and (type<=-set types1 types2)
-                (type<=-set types2 types1))
-           t)))
+          (every/type (lambda (x y-element)
+                         (any/type #'type= y-element x))
+                       x y)))
+    (and/type (type<=-set types1 types2)
+              (type<=-set types2 types1))))

 
 ;;; Two intersection types are equal if their subtypes are equal sets.
 ;;;
 
 ;;; Two intersection types are equal if their subtypes are equal sets.
 ;;;

@@ -1914,21 +2447,94 @@
             (intersection-type-types type2)))
 
 (defun %intersection-complex-subtypep-arg1 (type1 type2)
             (intersection-type-types type2)))
 
 (defun %intersection-complex-subtypep-arg1 (type1 type2)

-  (any/type (swapped-args-fun #'csubtypep)
-           type2
-           (intersection-type-types type1)))
+  (type= type1 (type-intersection type1 type2)))

 
 

-(!define-type-method (intersection :simple-subtypep) (type1 type2)
+(defun %intersection-simple-subtypep (type1 type2)

   (every/type #'%intersection-complex-subtypep-arg1
              type1
              (intersection-type-types type2)))
 
   (every/type #'%intersection-complex-subtypep-arg1
              type1
              (intersection-type-types type2)))
 

+(!define-type-method (intersection :simple-subtypep) (type1 type2)
+  (%intersection-simple-subtypep type1 type2))
+  

 (!define-type-method (intersection :complex-subtypep-arg1) (type1 type2)
   (%intersection-complex-subtypep-arg1 type1 type2))
 
 (!define-type-method (intersection :complex-subtypep-arg1) (type1 type2)
   (%intersection-complex-subtypep-arg1 type1 type2))
 

-(!define-type-method (intersection :complex-subtypep-arg2) (type1 type2)
+(defun %intersection-complex-subtypep-arg2 (type1 type2)

   (every/type #'csubtypep type1 (intersection-type-types type2)))
 
   (every/type #'csubtypep type1 (intersection-type-types type2)))
 

+(!define-type-method (intersection :complex-subtypep-arg2) (type1 type2)
+  (%intersection-complex-subtypep-arg2 type1 type2))
+
+;;; FIXME: This will look eeriely familiar to readers of the UNION
+;;; :SIMPLE-INTERSECTION2 :COMPLEX-INTERSECTION2 method.  That's
+;;; because it was generated by cut'n'paste methods.  Given that
+;;; intersections and unions have all sorts of symmetries known to
+;;; mathematics, it shouldn't be beyond the ken of some programmers to
+;;; reflect those symmetries in code in a way that ties them together
+;;; more strongly than having two independent near-copies :-/
+(!define-type-method (intersection :simple-union2 :complex-union2)
+                    (type1 type2)
+  ;; Within this method, type2 is guaranteed to be an intersection
+  ;; type:
+  (aver (intersection-type-p type2))
+  ;; Make sure to call only the applicable methods...
+  (cond ((and (intersection-type-p type1)
+             (%intersection-simple-subtypep type1 type2)) type2)
+       ((and (intersection-type-p type1)
+             (%intersection-simple-subtypep type2 type1)) type1)
+       ((and (not (intersection-type-p type1))
+             (%intersection-complex-subtypep-arg2 type1 type2))
+        type2)
+       ((and (not (intersection-type-p type1))
+             (%intersection-complex-subtypep-arg1 type2 type1))
+        type1)
+       ;; KLUDGE: This special (and somewhat hairy) magic is required
+       ;; to deal with the RATIONAL/INTEGER special case.  The UNION
+       ;; of (INTEGER * -1) and (AND (RATIONAL * -1/2) (NOT INTEGER))
+       ;; should be (RATIONAL * -1/2) -- CSR, 2003-02-28
+       ((and (csubtypep type2 (specifier-type 'ratio))
+             (numeric-type-p type1)
+             (csubtypep type1 (specifier-type 'integer))
+             (csubtypep type2
+                        (make-numeric-type
+                         :class 'rational
+                         :complexp nil
+                         :low (if (null (numeric-type-low type1))
+                                  nil
+                                  (list (1- (numeric-type-low type1))))
+                         :high (if (null (numeric-type-high type1))
+                                   nil
+                                   (list (1+ (numeric-type-high type1)))))))
+        (type-union type1
+                    (apply #'type-intersection
+                           (remove (specifier-type '(not integer))
+                                   (intersection-type-types type2)
+                                   :test #'type=))))
+       (t
+        (let ((accumulator *universal-type*))
+          (do ((t2s (intersection-type-types type2) (cdr t2s)))
+              ((null t2s) accumulator)
+            (let ((union (type-union type1 (car t2s))))
+              (when (union-type-p union)
+                ;; we have to give up here -- there are all sorts of
+                ;; ordering worries, but it's better than before.
+                ;; Doing exactly the same as in the UNION
+                ;; :SIMPLE/:COMPLEX-INTERSECTION2 method causes stack
+                ;; overflow with the mutual recursion never bottoming
+                ;; out.
+                (if (and (eq accumulator *universal-type*)
+                         (null (cdr t2s)))
+                    ;; KLUDGE: if we get here, we have a partially
+                    ;; simplified result.  While this isn't by any
+                    ;; means a universal simplification, including
+                    ;; this logic here means that we can get (OR
+                    ;; KEYWORD (NOT KEYWORD)) canonicalized to T.
+                    (return union)
+                    (return nil)))
+              (setf accumulator
+                    (type-intersection accumulator union))))))))
+        

 (!def-type-translator and (&whole whole &rest type-specifiers)
   (apply #'type-intersection
         (mapcar #'specifier-type
 (!def-type-translator and (&whole whole &rest type-specifiers)
   (apply #'type-intersection
         (mapcar #'specifier-type

@@ -1938,35 +2544,109 @@
 
 (!define-type-class union)
 
 
 (!define-type-class union)
 

-;;; The LIST type has a special name. Other union types just get
-;;; mechanically unparsed.
+;;; The LIST, FLOAT and REAL types have special names.  Other union
+;;; types just get mechanically unparsed.

 (!define-type-method (union :unparse) (type)
   (declare (type ctype type))
 (!define-type-method (union :unparse) (type)
   (declare (type ctype type))

-  (if (type= type (specifier-type 'list))
-      'list
-      `(or ,@(mapcar #'type-specifier (union-type-types type)))))
-
+  (cond
+    ((type= type (specifier-type 'list)) 'list)
+    ((type= type (specifier-type 'float)) 'float)
+    ((type= type (specifier-type 'real)) 'real)
+    ((type= type (specifier-type 'sequence)) 'sequence)
+    ((type= type (specifier-type 'bignum)) 'bignum)
+    (t `(or ,@(mapcar #'type-specifier (union-type-types type))))))
+
+;;; Two union types are equal if they are each subtypes of each
+;;; other. We need to be this clever because our complex subtypep
+;;; methods are now more accurate; we don't get infinite recursion
+;;; because the simple-subtypep method delegates to complex-subtypep
+;;; of the individual types of type1. - CSR, 2002-04-09
+;;;
+;;; Previous comment, now obsolete, but worth keeping around because
+;;; it is true, though too strong a condition:
+;;;

 ;;; Two union types are equal if their subtypes are equal sets.
 (!define-type-method (union :simple-=) (type1 type2)
 ;;; Two union types are equal if their subtypes are equal sets.
 (!define-type-method (union :simple-=) (type1 type2)

-  (type=-set (union-type-types type1)
-            (union-type-types type2)))
+  (multiple-value-bind (subtype certain?)
+      (csubtypep type1 type2)
+    (if subtype
+       (csubtypep type2 type1)
+       ;; we might as well become as certain as possible.
+       (if certain?
+           (values nil t)
+           (multiple-value-bind (subtype certain?)
+               (csubtypep type2 type1)
+             (declare (ignore subtype))
+             (values nil certain?))))))
+
+(!define-type-method (union :complex-=) (type1 type2)
+  (declare (ignore type1))
+  (if (some #'type-might-contain-other-types-p 
+           (union-type-types type2))
+      (values nil nil)
+      (values nil t)))

 
 

-;;; Similarly, a union type is a subtype of another if every element
-;;; of TYPE1 is a subtype of some element of TYPE2.
-(!define-type-method (union :simple-subtypep) (type1 type2)
+;;; Similarly, a union type is a subtype of another if and only if
+;;; every element of TYPE1 is a subtype of TYPE2.
+(defun union-simple-subtypep (type1 type2)

   (every/type (swapped-args-fun #'union-complex-subtypep-arg2)
              type2
              (union-type-types type1)))
 
   (every/type (swapped-args-fun #'union-complex-subtypep-arg2)
              type2
              (union-type-types type1)))
 

+(!define-type-method (union :simple-subtypep) (type1 type2)
+  (union-simple-subtypep type1 type2))
+  

 (defun union-complex-subtypep-arg1 (type1 type2)
   (every/type (swapped-args-fun #'csubtypep)
              type2
              (union-type-types type1)))
 (defun union-complex-subtypep-arg1 (type1 type2)
   (every/type (swapped-args-fun #'csubtypep)
              type2
              (union-type-types type1)))

+

 (!define-type-method (union :complex-subtypep-arg1) (type1 type2)
   (union-complex-subtypep-arg1 type1 type2))
 
 (defun union-complex-subtypep-arg2 (type1 type2)
 (!define-type-method (union :complex-subtypep-arg1) (type1 type2)
   (union-complex-subtypep-arg1 type1 type2))
 
 (defun union-complex-subtypep-arg2 (type1 type2)

-  (any/type #'csubtypep type1 (union-type-types type2)))
+  (multiple-value-bind (sub-value sub-certain?)
+      ;; was: (any/type #'csubtypep type1 (union-type-types type2)),
+      ;; which turns out to be too restrictive, causing bug 91.
+      ;;
+      ;; the following reimplementation might look dodgy.  It is
+      ;; dodgy. It depends on the union :complex-= method not doing
+      ;; very much work -- certainly, not using subtypep. Reasoning:
+      (progn
+       ;; At this stage, we know that type2 is a union type and type1
+       ;; isn't. We might as well check this, though:
+       (aver (union-type-p type2))
+       (aver (not (union-type-p type1)))
+       ;;     A is a subset of (B1 u B2)
+       ;; <=> A n (B1 u B2) = A
+       ;; <=> (A n B1) u (A n B2) = A
+       ;;
+       ;; But, we have to be careful not to delegate this type= to
+       ;; something that could invoke subtypep, which might get us
+       ;; back here -> stack explosion. We therefore ensure that the
+       ;; second type (which is the one that's dispatched on) is
+       ;; either a union type (where we've ensured that the complex-=
+       ;; method will not call subtypep) or something with no union
+       ;; types involved, in which case we'll never come back here.
+       ;;
+       ;; If we don't do this, then e.g.
+       ;; (SUBTYPEP '(MEMBER 3) '(OR (SATISFIES FOO) (SATISFIES BAR)))
+       ;; would loop infinitely, as the member :complex-= method is
+       ;; implemented in terms of subtypep.
+       ;;
+       ;; Ouch. - CSR, 2002-04-10
+       (type= type1
+              (apply #'type-union
+                     (mapcar (lambda (x) (type-intersection type1 x))
+                             (union-type-types type2)))))
+    (if sub-certain?
+       (values sub-value sub-certain?)
+       ;; The ANY/TYPE expression above is a sufficient condition for
+       ;; subsetness, but not a necessary one, so we might get a more
+       ;; certain answer by this CALL-NEXT-METHOD-ish step when the
+       ;; ANY/TYPE expression is uncertain.
+       (invoke-complex-subtypep-arg1-method type1 type2))))
+

 (!define-type-method (union :complex-subtypep-arg2) (type1 type2)
   (union-complex-subtypep-arg2 type1 type2))
 
 (!define-type-method (union :complex-subtypep-arg2) (type1 type2)
   (union-complex-subtypep-arg2 type1 type2))
 

@@ -1984,9 +2664,19 @@
   ;; CSUBTYPEP, in order to avoid possibly invoking any methods which
   ;; might in turn invoke (TYPE-INTERSECTION2 TYPE1 TYPE2) and thus
   ;; cause infinite recursion.
   ;; CSUBTYPEP, in order to avoid possibly invoking any methods which
   ;; might in turn invoke (TYPE-INTERSECTION2 TYPE1 TYPE2) and thus
   ;; cause infinite recursion.

-  (cond ((union-complex-subtypep-arg2 type1 type2)
+  ;;
+  ;; Within this method, type2 is guaranteed to be a union type:
+  (aver (union-type-p type2))
+  ;; Make sure to call only the applicable methods...
+  (cond ((and (union-type-p type1)
+             (union-simple-subtypep type1 type2)) type1)
+       ((and (union-type-p type1)
+             (union-simple-subtypep type2 type1)) type2)
+       ((and (not (union-type-p type1))
+             (union-complex-subtypep-arg2 type1 type2))

         type1)
         type1)

-       ((union-complex-subtypep-arg1 type2 type1)
+       ((and (not (union-type-p type1))
+             (union-complex-subtypep-arg1 type2 type1))

         type2)
        (t 
         ;; KLUDGE: This code accumulates a sequence of TYPE-UNION2
         type2)
        (t 
         ;; KLUDGE: This code accumulates a sequence of TYPE-UNION2

@@ -2004,12 +2694,8 @@
         (let ((accumulator *empty-type*))
           (dolist (t2 (union-type-types type2) accumulator)
             (setf accumulator
         (let ((accumulator *empty-type*))
           (dolist (t2 (union-type-types type2) accumulator)
             (setf accumulator

-                  (type-union2 accumulator
-                               (type-intersection type1 t2)))
-            ;; When our result isn't simple any more (because
-            ;; TYPE-UNION2 was unable to give us a simple result)
-            (unless accumulator
-              (return nil)))))))
+                  (type-union accumulator
+                              (type-intersection type1 t2))))))))

 
 (!def-type-translator or (&rest type-specifiers)
   (apply #'type-union
 
 (!def-type-translator or (&rest type-specifiers)
   (apply #'type-union

@@ -2021,8 +2707,9 @@
 (!define-type-class cons)
 
 (!def-type-translator cons (&optional (car-type-spec '*) (cdr-type-spec '*))
 (!define-type-class cons)
 
 (!def-type-translator cons (&optional (car-type-spec '*) (cdr-type-spec '*))

-  (make-cons-type (specifier-type car-type-spec)
-                 (specifier-type cdr-type-spec)))
+  (let ((car-type (specifier-type car-type-spec))
+       (cdr-type (specifier-type cdr-type-spec)))
+    (make-cons-type car-type cdr-type)))

  
 (!define-type-method (cons :unparse) (type)
   (let ((car-eltype (type-specifier (cons-type-car-type type)))
  
 (!define-type-method (cons :unparse) (type)
   (let ((car-eltype (type-specifier (cons-type-car-type type)))

@@ -2055,13 +2742,35 @@
        (car-type2 (cons-type-car-type type2))
        (cdr-type1 (cons-type-cdr-type type1))
        (cdr-type2 (cons-type-cdr-type type2)))
        (car-type2 (cons-type-car-type type2))
        (cdr-type1 (cons-type-cdr-type type1))
        (cdr-type2 (cons-type-cdr-type type2)))

-    (cond ((type= car-type1 car-type2)
-          (make-cons-type car-type1
-                          (type-union cdr-type1 cdr-type2)))
-         ((type= cdr-type1 cdr-type2)
-          (make-cons-type (type-union cdr-type1 cdr-type2)
-                          cdr-type1)))))
-
+    ;; UGH.  -- CSR, 2003-02-24
+    (macrolet ((frob-car (car1 car2 cdr1 cdr2)
+                `(type-union
+                  (make-cons-type ,car1 (type-union ,cdr1 ,cdr2))
+                  (make-cons-type
+                   (type-intersection ,car2
+                    (specifier-type
+                     `(not ,(type-specifier ,car1))))
+                   ,cdr2))))
+      (cond ((type= car-type1 car-type2)
+            (make-cons-type car-type1
+                            (type-union cdr-type1 cdr-type2)))
+           ((type= cdr-type1 cdr-type2)
+            (make-cons-type (type-union car-type1 car-type2)
+                            cdr-type1))
+           ((csubtypep car-type1 car-type2)
+            (frob-car car-type1 car-type2 cdr-type1 cdr-type2))
+           ((csubtypep car-type2 car-type1)
+            (frob-car car-type2 car-type1 cdr-type2 cdr-type1))
+           ;; Don't put these in -- consider the effect of taking the
+           ;; union of (CONS (INTEGER 0 2) (INTEGER 5 7)) and
+           ;; (CONS (INTEGER 0 3) (INTEGER 5 6)).
+           #+nil
+           ((csubtypep cdr-type1 cdr-type2)
+            (frob-cdr car-type1 car-type2 cdr-type1 cdr-type2))
+           #+nil
+           ((csubtypep cdr-type2 cdr-type1)
+            (frob-cdr car-type2 car-type1 cdr-type2 cdr-type1))))))
+           

 (!define-type-method (cons :simple-intersection2) (type1 type2)
   (declare (type cons-type type1 type2))
   (let (car-int2
 (!define-type-method (cons :simple-intersection2) (type1 type2)
   (declare (type cons-type type1 type2))
   (let (car-int2

@@ -2124,14 +2833,15 @@
                                       (dimensions '*))
   (specialize-array-type
    (make-array-type :dimensions (canonical-array-dimensions dimensions)
                                       (dimensions '*))
   (specialize-array-type
    (make-array-type :dimensions (canonical-array-dimensions dimensions)

+                    :complexp :maybe

                    :element-type (specifier-type element-type))))
 
 (!def-type-translator simple-array (&optional (element-type '*)
                                              (dimensions '*))
   (specialize-array-type
    (make-array-type :dimensions (canonical-array-dimensions dimensions)
                    :element-type (specifier-type element-type))))
 
 (!def-type-translator simple-array (&optional (element-type '*)
                                              (dimensions '*))
   (specialize-array-type
    (make-array-type :dimensions (canonical-array-dimensions dimensions)

-                   :element-type (specifier-type element-type)
-                   :complexp nil)))
+                    :complexp nil
+                   :element-type (specifier-type element-type))))

 \f
 ;;;; utilities shared between cross-compiler and target system
 
 \f
 ;;;; utilities shared between cross-compiler and target system
 

@@ -2140,8 +2850,8 @@
 (defun defined-ftype-matches-declared-ftype-p (defined-ftype declared-ftype)
   (declare (type ctype defined-ftype declared-ftype))
   (flet ((is-built-in-class-function-p (ctype)
 (defun defined-ftype-matches-declared-ftype-p (defined-ftype declared-ftype)
   (declare (type ctype defined-ftype declared-ftype))
   (flet ((is-built-in-class-function-p (ctype)

-          (and (built-in-class-p ctype)
-               (eq (built-in-class-%name ctype) 'function))))
+          (and (built-in-classoid-p ctype)
+               (eq (built-in-classoid-name ctype) 'function))))

     (cond (;; DECLARED-FTYPE could certainly be #<BUILT-IN-CLASS FUNCTION>;
           ;; that's what happens when we (DECLAIM (FTYPE FUNCTION FOO)).
           (is-built-in-class-function-p declared-ftype)
     (cond (;; DECLARED-FTYPE could certainly be #<BUILT-IN-CLASS FUNCTION>;
           ;; that's what happens when we (DECLAIM (FTYPE FUNCTION FOO)).
           (is-built-in-class-function-p declared-ftype)