updated for version 7.4.192
Problem:    Memory leak when giving E853.
Solution:   Free the argument. (Dominique Pelle)
diff --git a/src/eval.c b/src/eval.c
index 85c4031..59cfd12 100644
--- a/src/eval.c
+++ b/src/eval.c
@@ -21457,6 +21457,7 @@
 		if (STRCMP(((char_u **)(newargs.ga_data))[i], arg) == 0)
 		{
 		    EMSG2(_("E853: Duplicate argument name: %s"), arg);
+		    vim_free(arg);
 		    goto erret;
 		}