diff --git a/core/variant_call.cpp b/core/variant_call.cpp
index 0284c4d866a..0c03a0d9ae3 100644
--- a/core/variant_call.cpp
+++ b/core/variant_call.cpp
@@ -101,9 +101,10 @@ struct _VariantCall {
 				const Variant *newargs[VARIANT_ARG_MAX];
 				for (int i = 0; i < p_argcount; i++)
 					newargs[i] = p_args[i];
-				int defargcount = def_argcount;
+				// fill in any remaining parameters with defaults
+				int first_default_arg = arg_count - def_argcount;
 				for (int i = p_argcount; i < arg_count; i++)
-					newargs[i] = &default_args[defargcount - (i - p_argcount) - 1]; //default arguments
+					newargs[i] = &default_args[i - first_default_arg];
 #ifdef DEBUG_ENABLED
 				if (!verify_arguments(newargs, r_error))
 					return;