From 876aff85c275f885a731b6137486cfa48115df67 Mon Sep 17 00:00:00 2001
From: Paulo Matos <pmatos@linki.tools>
Date: Fri, 17 Apr 2020 21:55:17 +0200
Subject: [PATCH] Constrain the values of a and b in function not to be both
 NULL (#3106)

Fixes #2686
---
 racket/src/racket/src/thread.c | 4 +++-
 1 file changed, 3 insertions(+), 1 deletion(-)

diff --git a/racket/src/racket/src/thread.c b/racket/src/racket/src/thread.c
index ebc7c14917..4e9b22c05f 100644
--- a/racket/src/racket/src/thread.c
+++ b/racket/src/racket/src/thread.c
@@ -6450,7 +6450,9 @@ static void *splice_ptr_array(void **a, int al, void **b, int bl, int i)
 {
   void **r;
   int j;
-  
+
+  MZ_ASSERT (a != NULL || b != NULL);
+
   r = MALLOC_N(void*, al + bl - 1);
 
   if (a)