diff --git a/lisp/loadhist.el b/lisp/loadhist.el
index 375c64812ec..51f1be4071a 100644
--- a/lisp/loadhist.el
+++ b/lisp/loadhist.el
@@ -190,7 +190,7 @@ unloading."
       ;; Unloading a file whose definition is "inactive" (i.e. has been
       ;; overridden by another file): just remove it from the history,
       ;; so future unloading of that other file has a chance to DTRT.
-      (let* ((tmp (plist-member hist loadhist-unload-filename))
+      (let* ((tmp (plist-member hist loadhist-unload-filename #'equal))
              (pos (- (length hist) (length tmp))))
         (cl-assert (> pos 1))
         (setcdr (nthcdr (- pos 2) hist) (cdr tmp)))))))
diff --git a/src/data.c b/src/data.c
index da8ca42e565..4973d577c1c 100644
--- a/src/data.c
+++ b/src/data.c
@@ -937,7 +937,7 @@ add_to_function_history (Lisp_Object symbol, Lisp_Object olddef)
     if (NILP (XCDR (tail)) && STRINGP (XCAR (tail)))
       file = XCAR (tail);
 
-  Lisp_Object tem = plist_member (past, file);
+  Lisp_Object tem = Fplist_member (past, file, Qequal);
   if (!NILP (tem))
     { /* New def from a file used before.
          Overwrite the previous record associated with this file.  */