This fixes the unlikely event that the generated hashValue happens to be the equal to Int.min, in which case the abs value of it would be Int.max + 1 causing overflow.

Author: Linslav

Hash Table/HashTable.playground/Sources/HashTable.swift

@@ -131,7 +131,7 @@ public struct HashTable<Key: Hashable, Value> {
      Returns the given key's array index.
      */
     private func index(forKey key: Key) -> Int {
-        return abs(key.hashValue) % buckets.count
+        return abs(key.hashValue % buckets.count)
     }
 }
 

Hash Table/README.markdown

@@ -141,7 +141,7 @@ The hash table does not do anything yet, so let's add the remaining functionalit
 
 ```swift
   private func index(forKey key: Key) -> Int {
-    return abs(key.hashValue) % buckets.count
+    return abs(key.hashValue % buckets.count)
   }
 ```