1 files changed, 12 insertions, 0 deletions
diff --git a/mcs/class/referencesource/mscorlib/system/runtime/compilerservices/AsyncMethodBuilder.cs b/mcs/class/referencesource/mscorlib/system/runtime/compilerservices/AsyncMethodBuilder.cs
index fa6b3d92ca8..5c6833f33e7 100644
--- a/mcs/class/referencesource/mscorlib/system/runtime/compilerservices/AsyncMethodBuilder.cs
+++ b/mcs/class/referencesource/mscorlib/system/runtime/compilerservices/AsyncMethodBuilder.cs
@@ -825,16 +825,28 @@ namespace System.Runtime.CompilerServices
             // so that they won't "leak" out of the first await.
 
             Thread currentThread = Thread.CurrentThread;
+#if MONO
+            ExecutionContext.Switcher ecs = default (ExecutionContext.Switcher);
+#else
             ExecutionContextSwitcher ecs = default(ExecutionContextSwitcher);
+#endif
             RuntimeHelpers.PrepareConstrainedRegions();
             try
             {
+#if MONO
+                currentThread.BranchExecutionContext (out ecs);
+#else
                 ExecutionContext.EstablishCopyOnWriteScope(currentThread, false, ref ecs);
+#endif
                 stateMachine.MoveNext();
             }
             finally
             {
+#if MONO
+                currentThread.RestoreExecutionContext (ref ecs);
+#else
                 ecs.Undo(currentThread);
+#endif
             }
         }