diff --git a/src/random.h b/src/random.h
index 22801ec1555..9d1f7517733 100644
--- a/src/random.h
+++ b/src/random.h
@@ -166,6 +166,7 @@ public:
     /** Generate a random integer in the range [0..range). */
     uint64_t randrange(uint64_t range) noexcept
     {
+        assert(range);
         --range;
         int bits = CountBits(range);
         while (true) {