X-Git-Url: https://www.chiark.greenend.org.uk/ucgi/~mdw/git/sod/blobdiff_plain/d1c01c331ae3f2994d65b9d41655b0d4f2fcbf3d..57b365324f35a6237602ab840c23f4f06c8c317c:/src/module-parse.lisp

diff --git a/src/module-parse.lisp b/src/module-parse.lisp
index 0a3cd28..747bdf7 100644
--- a/src/module-parse.lisp
+++ b/src/module-parse.lisp
@@ -267,7 +267,14 @@ (defun parse-class-body (scanner pset name supers)
 				  (continue ()
 				    (setf duff t)
 				    (list (find-sod-class "SodObject"))))))
-	      superclasses))
+	      (find-duplicates (lambda (first second)
+				 (declare (ignore second))
+				 (setf duff t)
+				 (cerror* "Class `~A' has duplicate ~
+					   direct superclass `~A'"
+					  name first))
+			       superclasses)
+	      (delete-duplicates superclasses)))
 	   (synthetic-name (or name
 			       (let ((var (synthetic-name)))
 				 (unless pset