X-Git-Url: http://repo.macrolet.net/gitweb/?a=blobdiff_plain;f=src%2Fcompiler%2Fgeneric%2Fprimtype.lisp;h=5bf2533b9c79d825e2cc26d7a24e07a85dc9dc36;hb=ec30c81b59228c659fd602f98b7d7c9fc162cc0f;hp=1492378df910fcbbdd10000f3955a3a358469dfd;hpb=f1ffbf976aaa50b7b22f126b97e34afe06a91210;p=sbcl.git

diff --git a/src/compiler/generic/primtype.lisp b/src/compiler/generic/primtype.lisp
index 1492378..5bf2533 100644
--- a/src/compiler/generic/primtype.lisp
+++ b/src/compiler/generic/primtype.lisp
@@ -313,27 +313,33 @@
                              (return (any)))))))))))
         (intersection-type
          (let ((types (intersection-type-types type))
-               (res (any))
-               (exact nil))
-           (dolist (type types (values res exact))
-             (when (eq type (specifier-type 'function))
-               ;; KLUDGE: Deal with (and function instance), both of which
-               ;; have an exact primitive type.
-               (return (part-of function)))
-             (multiple-value-bind (ptype ptype-exact)
-                   (primitive-type type)
-                 (when ptype-exact
-                   ;; Apart from the previous kludge exact primitive
-                   ;; types should match, if indeed there are any. It
-                   ;; may be that this assumption isn't really safe,
-                   ;; but at least we'll see what breaks. -- NS 20041104
-                   (aver (or (not exact) (eq ptype res)))
-                   (setq exact t))
-                 (when (or ptype-exact (and (not exact) (eq res (any))))
-                   ;; Try to find a narrower representation then
-                   ;; (any). Takes care of undecidable types in
-                   ;; intersections with decidable ones.
-                   (setq res ptype))))))
+               (res (any)))
+           ;; why NIL for the exact?  Well, we assume that the
+           ;; intersection type is in fact doing something for us:
+           ;; that is, that each of the types in the intersection is
+           ;; in fact cutting off some of the type lattice.  Since no
+           ;; intersection type is represented by a primitive type and
+           ;; primitive types are mutually exclusive, it follows that
+           ;; no intersection type can represent the entirety of the
+           ;; primitive type.  (And NIL is the conservative answer,
+           ;; anyway).  -- CSR, 2006-09-14
+           (dolist (type types (values res nil))
+             (multiple-value-bind (ptype)
+                 (primitive-type type)
+               (cond
+                 ;; if the result so far is (any), any improvement on
+                 ;; the specificity of the primitive type is valid.
+                 ((eq res (any))
+                  (setq res ptype))
+                 ;; if the primitive type returned is (any), the
+                 ;; result so far is valid.  Likewise, if the
+                 ;; primitive type is the same as the result so far,
+                 ;; everything is fine.
+                 ((or (eq ptype (any)) (eq ptype res)))
+                 ;; otherwise, we have something hairy and confusing,
+                 ;; such as (and condition funcallable-instance).
+                 ;; Punt.
+                 (t (return (any))))))))
         (member-type
          (let* ((members (member-type-members type))
                 (res (primitive-type-of (first members))))
@@ -348,34 +354,34 @@
         (named-type
          (ecase (named-type-name type)
            ((t *) (values *backend-t-primitive-type* t))
+           ((instance) (exactly instance))
+           ((funcallable-instance) (part-of function))
+           ((extended-sequence) (any))
            ((nil) (any))))
-       (character-set-type
-        (let ((pairs (character-set-type-pairs type)))
-          (if (and (= (length pairs) 1)
-                   (= (caar pairs) 0)
-                   (= (cdar pairs) (1- sb!xc:char-code-limit)))
-              (exactly character)
-              (part-of character))))
-       (built-in-classoid
-        (case (classoid-name type)
-          ((complex function instance
-                    system-area-pointer weak-pointer)
-           (values (primitive-type-or-lose (classoid-name type)) t))
-          (funcallable-instance
-           (part-of function))
-          (cons-type
-           (part-of list))
-          (t
-           (any))))
-       (fun-type
-        (exactly function))
-       (classoid
-        (if (csubtypep type (specifier-type 'function))
-            (part-of function)
-            (part-of instance)))
-       (ctype
-        (if (csubtypep type (specifier-type 'function))
-            (part-of function)
-            (any)))))))
+        (character-set-type
+         (let ((pairs (character-set-type-pairs type)))
+           (if (and (= (length pairs) 1)
+                    (= (caar pairs) 0)
+                    (= (cdar pairs) (1- sb!xc:char-code-limit)))
+               (exactly character)
+               (part-of character))))
+        (built-in-classoid
+         (case (classoid-name type)
+           ((complex function system-area-pointer weak-pointer)
+            (values (primitive-type-or-lose (classoid-name type)) t))
+           (cons-type
+            (part-of list))
+           (t
+            (any))))
+        (fun-type
+         (exactly function))
+        (classoid
+         (if (csubtypep type (specifier-type 'function))
+             (part-of function)
+             (part-of instance)))
+        (ctype
+         (if (csubtypep type (specifier-type 'function))
+             (part-of function)
+             (any)))))))
 
 (/show0 "primtype.lisp end of file")