diff --git a/src/fsharp/FSharp.Core.Unittests/LibraryTestFx.fs b/src/fsharp/FSharp.Core.Unittests/LibraryTestFx.fs
index ade35128f10..1fff5215bd7 100644
--- a/src/fsharp/FSharp.Core.Unittests/LibraryTestFx.fs
+++ b/src/fsharp/FSharp.Core.Unittests/LibraryTestFx.fs
@@ -115,11 +115,14 @@ module SurfaceArea =
             t.GetMembers()
             |> Array.map (fun v -> sprintf "%s: %s" (v.ReflectedType.ToString()) (v.ToString()))
             #endif
-            
-        types 
-        |> Array.collect getTypeMemberStrings
-        |> Array.sort
-        |> String.concat "\r\n"
+        
+        let actual =
+            types 
+            |> Array.collect getTypeMemberStrings
+            |> Array.sort
+            |> String.concat "\r\n"
+
+        asm,actual
     
     // verify public surface area matches expected
     let verify expected platform fileName =  
@@ -133,7 +136,8 @@ module SurfaceArea =
         let normalize (s:string) =
             Regex.Replace(s, "(\\r\\n|\\n)+", "\r\n").Trim([|'\r';'\n'|])
             
-        let actual = getActual () |> normalize
+        let asm, actualNotNormalized = getActual ()
+        let actual = actualNotNormalized |> normalize
         let expected = expected |> normalize
         
-        Assert.AreEqual(expected, actual, sprintf "\r\n%s\r\n\r\n Expected and actual surface area don't match. To see the delta, run\r\nwindiff %s %s" actual fileName logFile)
+        Assert.AreEqual(expected, actual, sprintf "\r\nAssembly: %A\r\n\r\n%s\r\n\r\n Expected and actual surface area don't match. To see the delta, run\r\nwindiff %s %s" asm actual fileName logFile)
diff --git a/src/fsharp/FSharp.Core.Unittests/SurfaceArea.portable259.fs b/src/fsharp/FSharp.Core.Unittests/SurfaceArea.portable259.fs
index 2114a808c20..7a73cd45a6b 100644
--- a/src/fsharp/FSharp.Core.Unittests/SurfaceArea.portable259.fs
+++ b/src/fsharp/FSharp.Core.Unittests/SurfaceArea.portable259.fs
@@ -560,6 +560,7 @@ Microsoft.FSharp.Control.FSharpAsync: Boolean Equals(System.Object)
 Microsoft.FSharp.Control.FSharpAsync: Int32 GetHashCode()
 Microsoft.FSharp.Control.FSharpAsync: Microsoft.FSharp.Control.FSharpAsync`1[Microsoft.FSharp.Control.FSharpAsync`1[T]] StartChild[T](Microsoft.FSharp.Control.FSharpAsync`1[T], Microsoft.FSharp.Core.FSharpOption`1[System.Int32])
 Microsoft.FSharp.Control.FSharpAsync: Microsoft.FSharp.Control.FSharpAsync`1[Microsoft.FSharp.Core.FSharpChoice`2[T,System.Exception]] Catch[T](Microsoft.FSharp.Control.FSharpAsync`1[T])
+Microsoft.FSharp.Control.FSharpAsync: Microsoft.FSharp.Control.FSharpAsync`1[Microsoft.FSharp.Core.FSharpOption`1[T]] Choice[T](System.Collections.Generic.IEnumerable`1[Microsoft.FSharp.Control.FSharpAsync`1[Microsoft.FSharp.Core.FSharpOption`1[T]]])
 Microsoft.FSharp.Control.FSharpAsync: Microsoft.FSharp.Control.FSharpAsync`1[Microsoft.FSharp.Core.Unit] AwaitTask(System.Threading.Tasks.Task)
 Microsoft.FSharp.Control.FSharpAsync: Microsoft.FSharp.Control.FSharpAsync`1[Microsoft.FSharp.Core.Unit] Ignore[T](Microsoft.FSharp.Control.FSharpAsync`1[T])
 Microsoft.FSharp.Control.FSharpAsync: Microsoft.FSharp.Control.FSharpAsync`1[Microsoft.FSharp.Core.Unit] Sleep(Int32)