Optimise LinqBridge.Enumerable.Cast for direct cast available.

(This changes the behaviour to return same type, but framework Linq has the same optimisation).
2017-01-04 14:52:30 +00:00
parent 3ae09a80f0
commit 1829b71255
1 changed files with 8 additions and 1 deletions
@@ -72,7 +72,14 @@ namespace Newtonsoft.Json.Utilities.LinqBridge
    {
      CheckNotNull(source, "source");

-      return CastYield<TResult>(source);
+        var servesItself = source as IEnumerable<TResult>;
+        if (servesItself != null
+            && (!(servesItself is TResult[]) || servesItself.GetType().GetElementType() == typeof(TResult)))
+        {
+            return servesItself;
+        }
+
+        return CastYield<TResult>(source);
    }

    private static IEnumerable<TResult> CastYield<TResult>(