diff --git a/src/hash.c b/src/hash.c
index e648e872..e3981c20 100644
--- a/src/hash.c
+++ b/src/hash.c
@@ -29,7 +29,7 @@ hash_cstring (char const *s, long size)
   int hash = s[0] * 37;
   if (s[0] != 0)
     if (s[1] != 0)
-      hash = hash + s[1] * 43;
+      hash = hash + (s[1] * 43);
   assert_msg (size != 0, "size");
   hash = hash % size;
   return hash;