diff --git a/rd-net/Lifetimes/Lifetimes/Lifetime.cs b/rd-net/Lifetimes/Lifetimes/Lifetime.cs
index 668b8022b..187c0c002 100644
--- a/rd-net/Lifetimes/Lifetimes/Lifetime.cs
+++ b/rd-net/Lifetimes/Lifetimes/Lifetime.cs
@@ -8,10 +8,6 @@
 using JetBrains.Diagnostics;
 using JetBrains.Threading;
 
-#if !NET35
-
-#endif
-
 namespace JetBrains.Lifetimes
 {
   /// <summary>
@@ -612,6 +608,7 @@ public async Task UsingNestedAsync([InstantHandle] Func<Lifetime, Task> action)
     [PublicAPI]
     public Lifetime KeepAlive(object @object)
     {
+      LifetimeDefinition.Log.Assert(!IsEternal);
       if (@object == null) throw new ArgumentNullException(nameof(@object));      
 
       return OnTermination(() => GC.KeepAlive(@object));
diff --git a/rd-net/Test.Lifetimes/Lifetimes/LifetimeTest.cs b/rd-net/Test.Lifetimes/Lifetimes/LifetimeTest.cs
index e2e2a755e..be4f3dc9c 100644
--- a/rd-net/Test.Lifetimes/Lifetimes/LifetimeTest.cs
+++ b/rd-net/Test.Lifetimes/Lifetimes/LifetimeTest.cs
@@ -7,8 +7,11 @@
 using JetBrains.Diagnostics;
 using JetBrains.Diagnostics.Internal;
 using JetBrains.Lifetimes;
-using JetBrains.Threading;
 using NUnit.Framework;
+#if !NET35
+using JetBrains.Threading;
+#endif
+
 // ReSharper disable MethodSupportsCancellation
 
 namespace Test.Lifetimes.Lifetimes
@@ -1414,5 +1417,20 @@ public void DefineLifetimeInheritTimeoutKindTest()
       
       Assert.AreEqual(LifetimeTerminationTimeoutKind.ExtraLong, OuterLifetime.Define(definition.Lifetime, "id", (ld, lf) => {}).TerminationTimeoutKind);
     }
+
+    [Test]
+    public void EternalLifetimeKeepalive()
+    {
+      Assert.DoesNotThrow(() =>
+      {
+        var o = new object();
+        Lifetime.Eternal.KeepAlive(o);
+      });
+      var ex = Assert.Throws<Exception>(() =>
+      {
+        TestLogger.ExceptionLogger.ThrowLoggedExceptions();
+      });
+      Assert.True(ex.Message.Contains("!IsEternal"));
+    }
   }
 }
\ No newline at end of file