diff --git a/lib/swift/Sources/TMap.swift b/lib/swift/Sources/TMap.swift
index dcf1481..8f52067 100644
--- a/lib/swift/Sources/TMap.swift
+++ b/lib/swift/Sources/TMap.swift
@@ -17,7 +17,7 @@
  * under the License.
  */
 
-public struct TMap<Key : TSerializable & Hashable, Value : TSerializable>: Collection, ExpressibleByDictionaryLiteral, Hashable, TSerializable {
+public struct TMap<Key : TSerializable & Hashable, Value : TSerializable & Hashable>: Collection, ExpressibleByDictionaryLiteral, Hashable, TSerializable {
   public typealias Storage = Dictionary<Key, Value>
   public typealias Element = Storage.Element
   public typealias Index = Storage.Index
@@ -111,15 +111,9 @@
   }
 
   /// Mark: Hashable
-  
-  public var hashValue: Int {
-    let prime = 31
-    var result = 1
-    for (key, value) in storage {
-      result = prime &* result &+ key.hashValue
-      result = prime &* result &+ value.hashValue
-    }
-    return result
+
+  public func hash(into hasher: inout Hasher) {
+    hasher.combine(storage)
   }
   
   /// Mark: TSerializable