diff --git a/client/deps/liblua/ldebug.c b/client/deps/liblua/ldebug.c
index a993ad65f..b29de55fc 100644
--- a/client/deps/liblua/ldebug.c
+++ b/client/deps/liblua/ldebug.c
@@ -105,10 +105,11 @@ static const char *upvalname(Proto *p, int uv) {
 
 static const char *findvararg(CallInfo *ci, int n, StkId *pos) {
     int nparams = clLvalue(ci->func)->p->numparams;
-    if (n >= ci->u.l.base - ci->func - nparams)
+    int nvararg = cast_int(ci->u.l.base - ci->func) - nparams;
+    if (n <= -nvararg)
         return NULL;  /* no such vararg */
     else {
-        *pos = ci->func + nparams + n;
+        *pos = ci->func + nparams - n;
         return "(*vararg)";  /* generic name for any vararg */
     }
 }
@@ -120,7 +121,7 @@ static const char *findlocal(lua_State *L, CallInfo *ci, int n,
     StkId base;
     if (isLua(ci)) {
         if (n < 0)  /* access to vararg values? */
-            return findvararg(ci, -n, pos);
+            return findvararg(ci, n, pos);
         else {
             base = ci->u.l.base;
             name = luaF_getlocalname(ci_func(ci)->p, n, currentpc(ci));