X-Git-Url: http://repo.macrolet.net/gitweb/?a=blobdiff_plain;f=src%2Fcode%2Ftarget-type.lisp;h=e561d872b6cf00a2c8adfd12a2fa51bb88d0cdce;hb=caf8bb05a82659e688c125b418783bc8a3bd2be8;hp=0c254486a4f15e9e5c08ebe9bcd9feb61e30be14;hpb=4eb1a6d3ad2b7dcc19ac0ec979a1eb1eb049659a;p=sbcl.git

diff --git a/src/code/target-type.lisp b/src/code/target-type.lisp
index 0c25448..e561d87 100644
--- a/src/code/target-type.lisp
+++ b/src/code/target-type.lisp
@@ -81,7 +81,26 @@
 	  (let ((predicate-name (second hairy-spec)))
 	    (declare (type symbol predicate-name)) ; by ANSI spec of SATISFIES
 	    (if (fboundp predicate-name)
-		(values (not (null (funcall predicate-name obj))) t)
+		(let* (;; "Is OBJ of the SATISFIES type?" represented
+		       ;; as a generalized boolean.
+		       ;;
+		       ;; (Why IGNORE-ERRORS? This code is used to try to
+		       ;; check type relationships at compile time. 
+		       ;; Passing only-slightly-twisted types like
+		       ;; (AND INTEGER (SATISFIES ODDP)) into the
+		       ;; rather-significantly-twisted type dispatch
+		       ;; system can easily give rise to oddities like
+		       ;; calling predicates like ODDP on values they
+		       ;; don't like. (E.g. on OBJ=#\NEWLINE when the
+		       ;; above type is tested for TYPE= against
+		       ;; STANDARD-CHAR, represented as a
+		       ;; MEMBER-TYPE.) In such cases, NIL seems to be
+		       ;; an appropriate answer to "is OBJ of the
+		       ;; SATISFIES type?")
+		       (gbool (ignore-errors (funcall predicate-name obj)))
+		       ;; RAW coerced to a pure BOOLEAN value
+		       (bool (not (not gbool))))
+		  (values bool t))
 		(values nil nil)))))))))
 
 ;;; Return the layout for an object. This is the basic operation for
@@ -132,13 +151,13 @@
 		   csubtypep-cache-clear
 		   type-intersection2-cache-clear
 		   values-type-intersection-cache-clear))
-      (funcall (symbol-function sym))))
+      (funcall (the function (symbol-function sym)))))
   (values))
 
-;;; Like TYPE-OF, only we return a CTYPE structure instead of a type
-;;; specifier, and we try to return the type most useful for type
-;;; checking, rather than trying to come up with the one that the user
-;;; might find most informative.
+;;; This is like TYPE-OF, only we return a CTYPE structure instead of
+;;; a type specifier, and we try to return the type most useful for
+;;; type checking, rather than trying to come up with the one that the
+;;; user might find most informative.
 (declaim (ftype (function (t) ctype) ctype-of))
 (defun-cached (ctype-of
 	       :hash-function (lambda (x) (logand (sxhash x) #x1FF))