--- util_expr_eval.c.orig	2019-01-19 15:17:38.457452578 +0100
+++ util_expr_eval.c	2019-01-19 15:19:21.799868801 +0100
@@ -2191,7 +2191,7 @@
         type = "Binary operator";
         break;
     default:
-        *parms->err = "Inavalid expression type in expr_lookup";
+        *parms->err = "Invalid expression type in expr_lookup";
         return !OK;
     }
     if (   parms->type == AP_EXPR_FUNC_OP_UNARY