diff --git a/codegen/cg_genattr.c b/codegen/cg_genattr.c
index 535852da..c3acc0dc 100644
--- a/codegen/cg_genattr.c
+++ b/codegen/cg_genattr.c
@@ -1532,7 +1532,7 @@ static int MarshalAsAttribute(ILGenInfo *info,
 			else
 			{
 				sizeParamIndex = attributeInfo->namedArgs[currentNamedArg].evalValue.un.i4Value;
-				if(sizeParamIndex <= 0)
+				if(sizeParamIndex < 0)
 				{
 					CGErrorForNode(info, attributeInfo->namedArgs[currentNamedArg].node,
 						_("The size parameter index must be >= 0"));