--- a/Implab/Safe.cs	Thu Oct 23 01:13:57 2014 +0400
+++ b/Implab/Safe.cs	Thu Oct 23 17:50:09 2014 +0400
@@ -44,7 +44,7 @@
         }
 
         [DebuggerStepThrough]
-        public static IPromise<T> GuargPromise<T>(Func<T> action) {
+        public static IPromise<T> InvokePromise<T>(Func<T> action) {
             ArgumentNotNull(action, "action");
 
             var p = new Promise<T>();
@@ -58,11 +58,11 @@
         }
 
         [DebuggerStepThrough]
-        public static IPromise<T> GuardPromise<T>(Func<IPromise<T>> action) {
+        public static IPromise<T> InvokePromise<T>(Func<IPromise<T>> action) {
             ArgumentNotNull(action, "action");
 
             try {
-                return action();
+                return action() ?? Promise<T>.ExceptionToPromise(new Exception("The action returned null"));
             } catch (Exception err) {
                 return Promise<T>.ExceptionToPromise(err);
             }