--- src/Symbol.cc.orig	2018-01-10 18:59:55.390738393 +0100
+++ src/Symbol.cc	2018-01-10 19:03:58.169098358 +0100
@@ -885,7 +885,7 @@ const bool can_set = (vs.name_class == N
                      (vs.name_class == NC_OPERATOR) ||
                      (vs.name_class == NC_UNUSED_USER_NAME);
              
-   Assert(nc == NC_FUNCTION || NC_OPERATOR || NC_UNUSED_USER_NAME);
+   Assert(nc == NC_FUNCTION || nc == NC_OPERATOR || nc == NC_UNUSED_USER_NAME);
 
    if (!can_set)   DEFN_ERROR;
    vs.sym_val.function = fun;