diff --git a/src/fsharp/FSharp.Core/async.fs b/src/fsharp/FSharp.Core/async.fs
index 6fb92fe5c1d..6afa26489de 100644
--- a/src/fsharp/FSharp.Core/async.fs
+++ b/src/fsharp/FSharp.Core/async.fs
@@ -156,27 +156,45 @@ namespace Microsoft.FSharp.Control
             assert storedExnCont.IsNone
             storedExnCont <- Some action
 
-    type TrampolineHolder() as this =
+    type TrampolineHolder() =
         let mutable trampoline = null
 
-        // Preallocate this delegate and keep it in the trampoline holder.
-        let sendOrPostCallbackWithTrampoline =
-            SendOrPostCallback (fun o ->
-                let f = unbox<unit -> AsyncReturn> o
-                // Reminder: the ignore below ignores an AsyncReturn.
-                this.ExecuteWithTrampoline f |> ignore)
-
-        // Preallocate this delegate and keep it in the trampoline holder.
-        let waitCallbackForQueueWorkItemWithTrampoline =
-            WaitCallback (fun o ->
-                let f = unbox<unit -> AsyncReturn> o
-                this.ExecuteWithTrampoline f |> ignore)
-
-        // Preallocate this delegate and keep it in the trampoline holder.
-        let threadStartCallbackForStartThreadWithTrampoline =
-            ParameterizedThreadStart (fun o ->
-                let f = unbox<unit -> AsyncReturn> o
-                this.ExecuteWithTrampoline f |> ignore)
+        // On-demand allocate this delegate and keep it in the trampoline holder.
+        let mutable sendOrPostCallbackWithTrampoline : SendOrPostCallback = null
+        let getSendOrPostCallbackWithTrampoline(this: TrampolineHolder) =
+            match sendOrPostCallbackWithTrampoline with 
+            | null ->
+                sendOrPostCallbackWithTrampoline <- 
+                    SendOrPostCallback (fun o ->
+                    let f = unbox<unit -> AsyncReturn> o
+                    // Reminder: the ignore below ignores an AsyncReturn.
+                    this.ExecuteWithTrampoline f |> ignore)
+            | _ -> ()
+            sendOrPostCallbackWithTrampoline
+
+        // On-demand allocate this delegate and keep it in the trampoline holder.
+        let mutable waitCallbackForQueueWorkItemWithTrampoline : WaitCallback = null
+        let getWaitCallbackForQueueWorkItemWithTrampoline(this: TrampolineHolder) =
+            match waitCallbackForQueueWorkItemWithTrampoline with 
+            | null ->
+                waitCallbackForQueueWorkItemWithTrampoline <-
+                    WaitCallback (fun o ->
+                        let f = unbox<unit -> AsyncReturn> o
+                        this.ExecuteWithTrampoline f |> ignore)
+            | _ -> ()
+            waitCallbackForQueueWorkItemWithTrampoline
+
+        // On-demand allocate this delegate and keep it in the trampoline holder.
+        let mutable threadStartCallbackForStartThreadWithTrampoline : ParameterizedThreadStart = null
+        let getThreadStartCallbackForStartThreadWithTrampoline(this: TrampolineHolder) =
+            match threadStartCallbackForStartThreadWithTrampoline with 
+            | null ->
+                threadStartCallbackForStartThreadWithTrampoline <-
+                    ParameterizedThreadStart (fun o ->
+                        let f = unbox<unit -> AsyncReturn> o
+                        this.ExecuteWithTrampoline f |> ignore)
+            | _ -> ()
+            threadStartCallbackForStartThreadWithTrampoline
 
         /// Execute an async computation after installing a trampoline on its synchronous stack.
         [<DebuggerHidden>]
@@ -184,12 +202,12 @@ namespace Microsoft.FSharp.Control
             trampoline <- Trampoline()
             trampoline.Execute firstAction
 
-        member _.PostWithTrampoline (syncCtxt: SynchronizationContext)  (f: unit -> AsyncReturn) =
-            syncCtxt.Post (sendOrPostCallbackWithTrampoline, state=(f |> box))
+        member this.PostWithTrampoline (syncCtxt: SynchronizationContext)  (f: unit -> AsyncReturn) =
+            syncCtxt.Post (getSendOrPostCallbackWithTrampoline(this), state=(f |> box))
             AsyncReturn.Fake()
 
-        member _.QueueWorkItemWithTrampoline (f: unit -> AsyncReturn) =
-            if not (ThreadPool.QueueUserWorkItem(waitCallbackForQueueWorkItemWithTrampoline, f |> box)) then
+        member this.QueueWorkItemWithTrampoline (f: unit -> AsyncReturn) =
+            if not (ThreadPool.QueueUserWorkItem(getWaitCallbackForQueueWorkItemWithTrampoline(this), f |> box)) then
                 failwith "failed to queue user work item"
             AsyncReturn.Fake()
 
@@ -199,8 +217,8 @@ namespace Microsoft.FSharp.Control
             | _ -> this.PostWithTrampoline syncCtxt f
 
         // This should be the only call to Thread.Start in this library. We must always install a trampoline.
-        member _.StartThreadWithTrampoline (f: unit -> AsyncReturn) =
-            Thread(threadStartCallbackForStartThreadWithTrampoline, IsBackground=true).Start(f|>box)
+        member this.StartThreadWithTrampoline (f: unit -> AsyncReturn) =
+            Thread(getThreadStartCallbackForStartThreadWithTrampoline(this), IsBackground=true).Start(f|>box)
             AsyncReturn.Fake()
 
         /// Save the exception continuation during propagation of an exception, or prior to raising an exception
@@ -287,18 +305,26 @@ namespace Microsoft.FSharp.Control
             contents.aux.ccont (OperationCanceledException (contents.aux.token))
 
         /// Check for trampoline hijacking.
-        member inline _.HijackCheckThenCall cont arg =
-            contents.aux.trampolineHolder.HijackCheckThenCall cont arg
+        // Note, this must make tailcalls, so may not be an instance member taking a byref argument,
+        /// nor call any members taking byref arguments.
+        static member inline HijackCheckThenCall (ctxt: AsyncActivation<'T>) cont arg =
+            ctxt.aux.trampolineHolder.HijackCheckThenCall cont arg
 
         /// Call the success continuation of the asynchronous execution context after checking for
         /// cancellation and trampoline hijacking.
         //   - Cancellation check
         //   - Hijack check
-        member ctxt.OnSuccess result =
+        //
+        // Note, this must make tailcalls, so may not be an instance member taking a byref argument.
+        static member Success (ctxt: AsyncActivation<'T>) result =
             if ctxt.IsCancellationRequested then
                 ctxt.OnCancellation ()
             else
-                ctxt.HijackCheckThenCall ctxt.cont result
+                AsyncActivation<'T>.HijackCheckThenCall ctxt ctxt.cont result
+
+        // For backwards API Compat
+        [<Obsolete("Call Success instead")>]
+        member ctxt.OnSuccess (result: 'T) = AsyncActivation<'T>.Success ctxt result
 
         /// Save the exception continuation during propagation of an exception, or prior to raising an exception
         member _.OnExceptionRaised() =
@@ -381,7 +407,7 @@ namespace Microsoft.FSharp.Control
         // Note: direct calls to this function may end up in user assemblies via inlining
         [<DebuggerHidden>]
         let Invoke (computation: Async<'T>) (ctxt: AsyncActivation<_>) : AsyncReturn =
-            ctxt.HijackCheckThenCall computation.Invoke ctxt
+            AsyncActivation<'T>.HijackCheckThenCall ctxt computation.Invoke ctxt
 
         /// Apply 'userCode' to 'arg'. If no exception is raised then call the normal continuation.  Used to implement
         /// 'finally' and 'when cancelled'.
@@ -401,7 +427,7 @@ namespace Microsoft.FSharp.Control
                     ctxt.OnExceptionRaised()
 
             if ok then
-                ctxt.HijackCheckThenCall ctxt.cont result
+                AsyncActivation<'T>.HijackCheckThenCall ctxt ctxt.cont result
             else
                 fake()
 
@@ -466,7 +492,7 @@ namespace Microsoft.FSharp.Control
             if ok then
                 match resOpt with
                 | None ->
-                    ctxt.HijackCheckThenCall ctxt.econt edi
+                    AsyncActivation<'T>.HijackCheckThenCall ctxt ctxt.econt edi
                 | Some res ->
                     Invoke res ctxt
             else
@@ -569,7 +595,7 @@ namespace Microsoft.FSharp.Control
         ///   - Hijack check (see OnSuccess)
         let inline CreateReturnAsync res =
             // Note: this code ends up in user assemblies via inlining
-            MakeAsync (fun ctxt -> ctxt.OnSuccess res)
+            MakeAsync (fun ctxt -> AsyncActivation.Success ctxt res)
 
         /// Runs the first process, takes its result, applies f and then runs the new process produced.
         ///   - Initial cancellation check (see Bind)
diff --git a/src/fsharp/FSharp.Core/async.fsi b/src/fsharp/FSharp.Core/async.fsi
index a49c75d8ec2..4f9f765bf6f 100644
--- a/src/fsharp/FSharp.Core/async.fsi
+++ b/src/fsharp/FSharp.Core/async.fsi
@@ -622,7 +622,12 @@ namespace Microsoft.FSharp.Control
         /// <summary>The F# compiler emits calls to this function to implement F# async expressions.</summary>
         ///
         /// <returns>A value indicating asynchronous execution.</returns>
-        member OnSuccess: 'T -> AsyncReturn
+        static member Success: AsyncActivation<'T> -> result: 'T -> AsyncReturn
+
+        /// <summary>The F# compiler emits calls to this function to implement F# async expressions.</summary>
+        ///
+        /// <returns>A value indicating asynchronous execution.</returns>
+        member OnSuccess: result: 'T -> AsyncReturn
 
         /// <summary>The F# compiler emits calls to this function to implement F# async expressions.</summary>
         member OnExceptionRaised: unit -> unit
diff --git a/src/fsharp/IlxGen.fs b/src/fsharp/IlxGen.fs
index 3659f0e753a..0d4d17043fa 100644
--- a/src/fsharp/IlxGen.fs
+++ b/src/fsharp/IlxGen.fs
@@ -3415,7 +3415,7 @@ and GenApp (cenv: cenv) cgbuf eenv (f, fty, tyargs, curriedArgs, m) sequel =
 
           // For instance method calls chop off some type arguments, which are already
           // carried by the class.  Also work out if it's a virtual call.
-          let _, virtualCall, newobj, isSuperInit, isSelfInit, _, _, _ = GetMemberCallInfo g (vref, valUseFlags)
+          let _, virtualCall, newobj, isSuperInit, isSelfInit, takesInstanceArg, _, _ = GetMemberCallInfo g (vref, valUseFlags)
 
           // numEnclILTypeArgs will include unit-of-measure args, unfortunately. For now, just cut-and-paste code from GetMemberCallInfo
           // @REVIEW: refactor this
@@ -3447,7 +3447,8 @@ and GenApp (cenv: cenv) cgbuf eenv (f, fty, tyargs, curriedArgs, m) sequel =
                   let isDllImport = IsValRefIsDllImport g vref
                   let hasByrefArg = mspec.FormalArgTypes |> List.exists (function ILType.Byref _ -> true | _ -> false)
                   let makesNoCriticalTailcalls = vref.MakesNoCriticalTailcalls
-                  CanTailcall((boxity=AsValue), ccallInfo, eenv.withinSEH, hasByrefArg, mustGenerateUnitAfterCall, isDllImport, isSelfInit, makesNoCriticalTailcalls, sequel)
+                  let hasStructObjArg = (boxity=AsValue) && takesInstanceArg
+                  CanTailcall(hasStructObjArg, ccallInfo, eenv.withinSEH, hasByrefArg, mustGenerateUnitAfterCall, isDllImport, isSelfInit, makesNoCriticalTailcalls, sequel)
               else
                   Normalcall
 
@@ -4193,7 +4194,8 @@ and GenILCall cenv cgbuf eenv (virt, valu, newobj, valUseFlags, isDllImport, ilM
     let boxity = (if valu then AsValue else AsObject)
     let mustGenerateUnitAfterCall = isNil returnTys
     let makesNoCriticalTailcalls = (newobj || not virt) // Don't tailcall for 'newobj', or 'call' to IL code
-    let tail = CanTailcall(valu, ccallInfo, eenv.withinSEH, hasByrefArg, mustGenerateUnitAfterCall, isDllImport, false, makesNoCriticalTailcalls, sequel)
+    let hasStructObjArg = valu && ilMethRef.CallingConv.IsInstance
+    let tail = CanTailcall(hasStructObjArg, ccallInfo, eenv.withinSEH, hasByrefArg, mustGenerateUnitAfterCall, isDllImport, false, makesNoCriticalTailcalls, sequel)
 
     let ilEnclArgTys = GenTypeArgs cenv.amap m eenv.tyenv enclArgTys
     let ilMethArgTys = GenTypeArgs cenv.amap m eenv.tyenv methArgTys
diff --git a/tests/FSharp.Core.UnitTests/SurfaceArea.fs b/tests/FSharp.Core.UnitTests/SurfaceArea.fs
index 0f1d985de66..d9b71fec864 100644
--- a/tests/FSharp.Core.UnitTests/SurfaceArea.fs
+++ b/tests/FSharp.Core.UnitTests/SurfaceArea.fs
@@ -513,6 +513,7 @@ Microsoft.FSharp.Control.AsyncActivation`1[T]: Boolean IsCancellationRequested
 Microsoft.FSharp.Control.AsyncActivation`1[T]: Boolean get_IsCancellationRequested()
 Microsoft.FSharp.Control.AsyncActivation`1[T]: Microsoft.FSharp.Control.AsyncReturn OnCancellation()
 Microsoft.FSharp.Control.AsyncActivation`1[T]: Microsoft.FSharp.Control.AsyncReturn OnSuccess(T)
+Microsoft.FSharp.Control.AsyncActivation`1[T]: Microsoft.FSharp.Control.AsyncReturn Success(Microsoft.FSharp.Control.AsyncActivation`1[T], T)
 Microsoft.FSharp.Control.AsyncActivation`1[T]: Void OnExceptionRaised()
 Microsoft.FSharp.Control.AsyncPrimitives: Microsoft.FSharp.Control.AsyncReturn Bind[T,TResult](Microsoft.FSharp.Control.AsyncActivation`1[T], Microsoft.FSharp.Control.FSharpAsync`1[TResult], Microsoft.FSharp.Core.FSharpFunc`2[TResult,Microsoft.FSharp.Control.FSharpAsync`1[T]])
 Microsoft.FSharp.Control.AsyncPrimitives: Microsoft.FSharp.Control.AsyncReturn CallThenInvoke[T,TResult](Microsoft.FSharp.Control.AsyncActivation`1[T], TResult, Microsoft.FSharp.Core.FSharpFunc`2[TResult,Microsoft.FSharp.Control.FSharpAsync`1[T]])
diff --git a/tests/fsharpqa/Source/CodeGen/EmittedIL/AsyncExpressionStepping/AsyncExpressionSteppingTest3.il.bsl b/tests/fsharpqa/Source/CodeGen/EmittedIL/AsyncExpressionStepping/AsyncExpressionSteppingTest3.il.bsl
index 6dfebd88b1e..76f073cdd4a 100644
--- a/tests/fsharpqa/Source/CodeGen/EmittedIL/AsyncExpressionStepping/AsyncExpressionSteppingTest3.il.bsl
+++ b/tests/fsharpqa/Source/CodeGen/EmittedIL/AsyncExpressionStepping/AsyncExpressionSteppingTest3.il.bsl
@@ -1,5 +1,5 @@
 
-//  Microsoft (R) .NET Framework IL Disassembler.  Version 4.6.1055.0
+//  Microsoft (R) .NET Framework IL Disassembler.  Version 4.8.3928.0
 //  Copyright (c) Microsoft Corporation.  All rights reserved.
 
 
@@ -13,7 +13,7 @@
 .assembly extern FSharp.Core
 {
   .publickeytoken = (B0 3F 5F 7F 11 D5 0A 3A )                         // .?_....:
-  .ver 4:4:3:0
+  .ver 5:0:0:0
 }
 .assembly AsyncExpressionSteppingTest3
 {
@@ -29,20 +29,20 @@
 }
 .mresource public FSharpSignatureData.AsyncExpressionSteppingTest3
 {
-  // Offset: 0x00000000 Length: 0x00000277
+  // Offset: 0x00000000 Length: 0x0000026B
 }
 .mresource public FSharpOptimizationData.AsyncExpressionSteppingTest3
 {
-  // Offset: 0x00000280 Length: 0x000000B1
+  // Offset: 0x00000270 Length: 0x000000B1
 }
 .module AsyncExpressionSteppingTest3.dll
-// MVID: {5AF5DDAE-6394-F35E-A745-0383AEDDF55A}
+// MVID: {60EDFA6D-6394-F35E-A745-03836DFAED60}
 .imagebase 0x00400000
 .file alignment 0x00000200
 .stackreserve 0x00100000
 .subsystem 0x0003       // WINDOWS_CUI
 .corflags 0x00000001    //  ILONLY
-// Image base: 0x04650000
+// Image base: 0x06D00000
 
 
 // =============== CLASS MEMBERS DECLARATION ===================
@@ -80,15 +80,17 @@
       .method public strict virtual instance class [FSharp.Core]Microsoft.FSharp.Control.AsyncReturn 
               Invoke(valuetype [FSharp.Core]Microsoft.FSharp.Control.AsyncActivation`1<int32> ctxt) cil managed
       {
-        // Code size       14 (0xe)
+        // Code size       15 (0xf)
         .maxstack  8
         .language '{AB4F38C9-B6E6-43BA-BE3B-58080B2CCCE3}', '{994B45C4-E6E9-11D2-903F-00C04FA302A1}', '{5A869D0B-6611-11D3-BD2A-0000F80849BD}'
-        .line 10,10 : 17,25 'C:\\GitHub\\dsyme\\visualfsharp\\tests\\fsharpqa\\Source\\CodeGen\\EmittedIL\\AsyncExpressionStepping\\AsyncExpressionSteppingTest3.fs'
-        IL_0000:  ldarga.s   ctxt
-        IL_0002:  ldarg.0
-        IL_0003:  ldfld      int32 AsyncExpressionSteppingTest3/AsyncExpressionSteppingTest3/'f3@10-1'::'value'
-        IL_0008:  call       instance class [FSharp.Core]Microsoft.FSharp.Control.AsyncReturn valuetype [FSharp.Core]Microsoft.FSharp.Control.AsyncActivation`1<int32>::OnSuccess(!0)
-        IL_000d:  ret
+        .line 10,10 : 17,25 'C:\\GitHub\\dsyme\\fsharp\\tests\\fsharpqa\\source\\CodeGen\\EmittedIL\\AsyncExpressionStepping\\AsyncExpressionSteppingTest3.fs'
+        IL_0000:  ldarg.1
+        IL_0001:  ldarg.0
+        IL_0002:  ldfld      int32 AsyncExpressionSteppingTest3/AsyncExpressionSteppingTest3/'f3@10-1'::'value'
+        IL_0007:  tail.
+        IL_0009:  call       class [FSharp.Core]Microsoft.FSharp.Control.AsyncReturn valuetype [FSharp.Core]Microsoft.FSharp.Control.AsyncActivation`1<int32>::Success(valuetype [FSharp.Core]Microsoft.FSharp.Control.AsyncActivation`1<!0>,
+                                                                                                                                                                       !0)
+        IL_000e:  ret
       } // end of method 'f3@10-1'::Invoke
 
     } // end of class 'f3@10-1'
diff --git a/tests/fsharpqa/Source/CodeGen/EmittedIL/AsyncExpressionStepping/AsyncExpressionSteppingTest4.il.bsl b/tests/fsharpqa/Source/CodeGen/EmittedIL/AsyncExpressionStepping/AsyncExpressionSteppingTest4.il.bsl
index ce54bd4945d..61ab690daf9 100644
--- a/tests/fsharpqa/Source/CodeGen/EmittedIL/AsyncExpressionStepping/AsyncExpressionSteppingTest4.il.bsl
+++ b/tests/fsharpqa/Source/CodeGen/EmittedIL/AsyncExpressionStepping/AsyncExpressionSteppingTest4.il.bsl
@@ -1,5 +1,5 @@
 
-//  Microsoft (R) .NET Framework IL Disassembler.  Version 4.6.1055.0
+//  Microsoft (R) .NET Framework IL Disassembler.  Version 4.8.3928.0
 //  Copyright (c) Microsoft Corporation.  All rights reserved.
 
 
@@ -13,7 +13,7 @@
 .assembly extern FSharp.Core
 {
   .publickeytoken = (B0 3F 5F 7F 11 D5 0A 3A )                         // .?_....:
-  .ver 4:4:3:0
+  .ver 5:0:0:0
 }
 .assembly AsyncExpressionSteppingTest4
 {
@@ -29,20 +29,20 @@
 }
 .mresource public FSharpSignatureData.AsyncExpressionSteppingTest4
 {
-  // Offset: 0x00000000 Length: 0x00000277
+  // Offset: 0x00000000 Length: 0x0000026B
 }
 .mresource public FSharpOptimizationData.AsyncExpressionSteppingTest4
 {
-  // Offset: 0x00000280 Length: 0x000000B1
+  // Offset: 0x00000270 Length: 0x000000B1
 }
 .module AsyncExpressionSteppingTest4.dll
-// MVID: {5AF5DDAE-6394-6D4B-A745-0383AEDDF55A}
+// MVID: {60EDFA6D-6394-6D4B-A745-03836DFAED60}
 .imagebase 0x00400000
 .file alignment 0x00000200
 .stackreserve 0x00100000
 .subsystem 0x0003       // WINDOWS_CUI
 .corflags 0x00000001    //  ILONLY
-// Image base: 0x028F0000
+// Image base: 0x06840000
 
 
 // =============== CLASS MEMBERS DECLARATION ===================
@@ -80,15 +80,17 @@
       .method public strict virtual instance class [FSharp.Core]Microsoft.FSharp.Control.AsyncReturn 
               Invoke(valuetype [FSharp.Core]Microsoft.FSharp.Control.AsyncActivation`1<int32> ctxt) cil managed
       {
-        // Code size       14 (0xe)
+        // Code size       15 (0xf)
         .maxstack  8
         .language '{AB4F38C9-B6E6-43BA-BE3B-58080B2CCCE3}', '{994B45C4-E6E9-11D2-903F-00C04FA302A1}', '{5A869D0B-6611-11D3-BD2A-0000F80849BD}'
-        .line 10,10 : 21,29 'C:\\GitHub\\dsyme\\visualfsharp\\tests\\fsharpqa\\Source\\CodeGen\\EmittedIL\\AsyncExpressionStepping\\AsyncExpressionSteppingTest4.fs'
-        IL_0000:  ldarga.s   ctxt
-        IL_0002:  ldarg.0
-        IL_0003:  ldfld      int32 AsyncExpressionSteppingTest4/AsyncExpressionSteppingTest4/'f4@10-2'::'value'
-        IL_0008:  call       instance class [FSharp.Core]Microsoft.FSharp.Control.AsyncReturn valuetype [FSharp.Core]Microsoft.FSharp.Control.AsyncActivation`1<int32>::OnSuccess(!0)
-        IL_000d:  ret
+        .line 10,10 : 21,29 'C:\\GitHub\\dsyme\\fsharp\\tests\\fsharpqa\\source\\CodeGen\\EmittedIL\\AsyncExpressionStepping\\AsyncExpressionSteppingTest4.fs'
+        IL_0000:  ldarg.1
+        IL_0001:  ldarg.0
+        IL_0002:  ldfld      int32 AsyncExpressionSteppingTest4/AsyncExpressionSteppingTest4/'f4@10-2'::'value'
+        IL_0007:  tail.
+        IL_0009:  call       class [FSharp.Core]Microsoft.FSharp.Control.AsyncReturn valuetype [FSharp.Core]Microsoft.FSharp.Control.AsyncActivation`1<int32>::Success(valuetype [FSharp.Core]Microsoft.FSharp.Control.AsyncActivation`1<!0>,
+                                                                                                                                                                       !0)
+        IL_000e:  ret
       } // end of method 'f4@10-2'::Invoke
 
     } // end of class 'f4@10-2'
diff --git a/tests/fsharpqa/Source/CodeGen/EmittedIL/AsyncExpressionStepping/AsyncExpressionSteppingTest6.il.bsl b/tests/fsharpqa/Source/CodeGen/EmittedIL/AsyncExpressionStepping/AsyncExpressionSteppingTest6.il.bsl
index 379ad6bbe7c..165e470e0bf 100644
--- a/tests/fsharpqa/Source/CodeGen/EmittedIL/AsyncExpressionStepping/AsyncExpressionSteppingTest6.il.bsl
+++ b/tests/fsharpqa/Source/CodeGen/EmittedIL/AsyncExpressionStepping/AsyncExpressionSteppingTest6.il.bsl
@@ -1,5 +1,5 @@
 
-//  Microsoft (R) .NET Framework IL Disassembler.  Version 4.6.1055.0
+//  Microsoft (R) .NET Framework IL Disassembler.  Version 4.8.3928.0
 //  Copyright (c) Microsoft Corporation.  All rights reserved.
 
 
@@ -13,7 +13,7 @@
 .assembly extern FSharp.Core
 {
   .publickeytoken = (B0 3F 5F 7F 11 D5 0A 3A )                         // .?_....:
-  .ver 4:4:3:0
+  .ver 5:0:0:0
 }
 .assembly AsyncExpressionSteppingTest6
 {
@@ -29,20 +29,20 @@
 }
 .mresource public FSharpSignatureData.AsyncExpressionSteppingTest6
 {
-  // Offset: 0x00000000 Length: 0x000002A3
+  // Offset: 0x00000000 Length: 0x00000297
 }
 .mresource public FSharpOptimizationData.AsyncExpressionSteppingTest6
 {
-  // Offset: 0x000002A8 Length: 0x000000BE
+  // Offset: 0x000002A0 Length: 0x000000BE
 }
 .module AsyncExpressionSteppingTest6.dll
-// MVID: {5AF5DDAE-6394-4FAD-A745-0383AEDDF55A}
+// MVID: {60EDFA6D-6394-4FAD-A745-03836DFAED60}
 .imagebase 0x00400000
 .file alignment 0x00000200
 .stackreserve 0x00100000
 .subsystem 0x0003       // WINDOWS_CUI
 .corflags 0x00000001    //  ILONLY
-// Image base: 0x04C40000
+// Image base: 0x071A0000
 
 
 // =============== CLASS MEMBERS DECLARATION ===================
@@ -55,7 +55,7 @@
          extends [mscorlib]System.Object
   {
     .custom instance void [FSharp.Core]Microsoft.FSharp.Core.CompilationMappingAttribute::.ctor(valuetype [FSharp.Core]Microsoft.FSharp.Core.SourceConstructFlags) = ( 01 00 07 00 00 00 00 00 ) 
-    .class auto ansi serializable sealed nested assembly beforefieldinit 'f2@10-4'
+    .class auto ansi serializable sealed nested assembly beforefieldinit 'f2@10-1'
            extends class [FSharp.Core]Microsoft.FSharp.Core.FSharpFunc`2<valuetype [FSharp.Core]Microsoft.FSharp.Control.AsyncActivation`1<int32>,class [FSharp.Core]Microsoft.FSharp.Control.AsyncReturn>
     {
       .field public int32 'value'
@@ -73,27 +73,29 @@
         IL_0001:  call       instance void class [FSharp.Core]Microsoft.FSharp.Core.FSharpFunc`2<valuetype [FSharp.Core]Microsoft.FSharp.Control.AsyncActivation`1<int32>,class [FSharp.Core]Microsoft.FSharp.Control.AsyncReturn>::.ctor()
         IL_0006:  ldarg.0
         IL_0007:  ldarg.1
-        IL_0008:  stfld      int32 AsyncExpressionSteppingTest6/AsyncExpressionSteppingTest6/'f2@10-4'::'value'
+        IL_0008:  stfld      int32 AsyncExpressionSteppingTest6/AsyncExpressionSteppingTest6/'f2@10-1'::'value'
         IL_000d:  ret
-      } // end of method 'f2@10-4'::.ctor
+      } // end of method 'f2@10-1'::.ctor
 
       .method public strict virtual instance class [FSharp.Core]Microsoft.FSharp.Control.AsyncReturn 
               Invoke(valuetype [FSharp.Core]Microsoft.FSharp.Control.AsyncActivation`1<int32> ctxt) cil managed
       {
-        // Code size       14 (0xe)
+        // Code size       15 (0xf)
         .maxstack  8
         .language '{AB4F38C9-B6E6-43BA-BE3B-58080B2CCCE3}', '{994B45C4-E6E9-11D2-903F-00C04FA302A1}', '{5A869D0B-6611-11D3-BD2A-0000F80849BD}'
-        .line 10,10 : 17,25 'C:\\GitHub\\dsyme\\visualfsharp\\tests\\fsharpqa\\Source\\CodeGen\\EmittedIL\\AsyncExpressionStepping\\AsyncExpressionSteppingTest6.fs'
-        IL_0000:  ldarga.s   ctxt
-        IL_0002:  ldarg.0
-        IL_0003:  ldfld      int32 AsyncExpressionSteppingTest6/AsyncExpressionSteppingTest6/'f2@10-4'::'value'
-        IL_0008:  call       instance class [FSharp.Core]Microsoft.FSharp.Control.AsyncReturn valuetype [FSharp.Core]Microsoft.FSharp.Control.AsyncActivation`1<int32>::OnSuccess(!0)
-        IL_000d:  ret
-      } // end of method 'f2@10-4'::Invoke
+        .line 10,10 : 17,25 'C:\\GitHub\\dsyme\\fsharp\\tests\\fsharpqa\\source\\CodeGen\\EmittedIL\\AsyncExpressionStepping\\AsyncExpressionSteppingTest6.fs'
+        IL_0000:  ldarg.1
+        IL_0001:  ldarg.0
+        IL_0002:  ldfld      int32 AsyncExpressionSteppingTest6/AsyncExpressionSteppingTest6/'f2@10-1'::'value'
+        IL_0007:  tail.
+        IL_0009:  call       class [FSharp.Core]Microsoft.FSharp.Control.AsyncReturn valuetype [FSharp.Core]Microsoft.FSharp.Control.AsyncActivation`1<int32>::Success(valuetype [FSharp.Core]Microsoft.FSharp.Control.AsyncActivation`1<!0>,
+                                                                                                                                                                       !0)
+        IL_000e:  ret
+      } // end of method 'f2@10-1'::Invoke
 
-    } // end of class 'f2@10-4'
+    } // end of class 'f2@10-1'
 
-    .class auto ansi serializable sealed nested assembly beforefieldinit 'f2@5-3'
+    .class auto ansi serializable sealed nested assembly beforefieldinit f2@5
            extends class [FSharp.Core]Microsoft.FSharp.Core.FSharpFunc`2<class [FSharp.Core]Microsoft.FSharp.Core.Unit,class [FSharp.Core]Microsoft.FSharp.Control.FSharpAsync`1<int32>>
     {
       .field public class [FSharp.Core]Microsoft.FSharp.Control.FSharpAsyncBuilder builder@
@@ -111,9 +113,9 @@
         IL_0001:  call       instance void class [FSharp.Core]Microsoft.FSharp.Core.FSharpFunc`2<class [FSharp.Core]Microsoft.FSharp.Core.Unit,class [FSharp.Core]Microsoft.FSharp.Control.FSharpAsync`1<int32>>::.ctor()
         IL_0006:  ldarg.0
         IL_0007:  ldarg.1
-        IL_0008:  stfld      class [FSharp.Core]Microsoft.FSharp.Control.FSharpAsyncBuilder AsyncExpressionSteppingTest6/AsyncExpressionSteppingTest6/'f2@5-3'::builder@
+        IL_0008:  stfld      class [FSharp.Core]Microsoft.FSharp.Control.FSharpAsyncBuilder AsyncExpressionSteppingTest6/AsyncExpressionSteppingTest6/f2@5::builder@
         IL_000d:  ret
-      } // end of method 'f2@5-3'::.ctor
+      } // end of method f2@5::.ctor
 
       .method public strict virtual instance class [FSharp.Core]Microsoft.FSharp.Control.FSharpAsync`1<int32> 
               Invoke(class [FSharp.Core]Microsoft.FSharp.Core.Unit unitVar) cil managed
@@ -150,20 +152,20 @@
         IL_0029:  stloc.2
         .line 10,10 : 17,25 ''
         IL_002a:  ldarg.0
-        IL_002b:  ldfld      class [FSharp.Core]Microsoft.FSharp.Control.FSharpAsyncBuilder AsyncExpressionSteppingTest6/AsyncExpressionSteppingTest6/'f2@5-3'::builder@
+        IL_002b:  ldfld      class [FSharp.Core]Microsoft.FSharp.Control.FSharpAsyncBuilder AsyncExpressionSteppingTest6/AsyncExpressionSteppingTest6/f2@5::builder@
         IL_0030:  stloc.3
         IL_0031:  ldloc.2
         IL_0032:  stloc.s    V_4
         IL_0034:  ldloc.s    V_4
-        IL_0036:  newobj     instance void AsyncExpressionSteppingTest6/AsyncExpressionSteppingTest6/'f2@10-4'::.ctor(int32)
+        IL_0036:  newobj     instance void AsyncExpressionSteppingTest6/AsyncExpressionSteppingTest6/'f2@10-1'::.ctor(int32)
         IL_003b:  tail.
         IL_003d:  call       class [FSharp.Core]Microsoft.FSharp.Control.FSharpAsync`1<!!0> [FSharp.Core]Microsoft.FSharp.Control.AsyncPrimitives::MakeAsync<int32>(class [FSharp.Core]Microsoft.FSharp.Core.FSharpFunc`2<valuetype [FSharp.Core]Microsoft.FSharp.Control.AsyncActivation`1<!!0>,class [FSharp.Core]Microsoft.FSharp.Control.AsyncReturn>)
         IL_0042:  ret
-      } // end of method 'f2@5-3'::Invoke
+      } // end of method f2@5::Invoke
 
-    } // end of class 'f2@5-3'
+    } // end of class f2@5
 
-    .class auto ansi serializable sealed nested assembly beforefieldinit 'f3@20-7'
+    .class auto ansi serializable sealed nested assembly beforefieldinit 'f3@20-5'
            extends class [FSharp.Core]Microsoft.FSharp.Core.FSharpFunc`2<valuetype [FSharp.Core]Microsoft.FSharp.Control.AsyncActivation`1<int32>,class [FSharp.Core]Microsoft.FSharp.Control.AsyncReturn>
     {
       .field public int32 'value'
@@ -181,26 +183,28 @@
         IL_0001:  call       instance void class [FSharp.Core]Microsoft.FSharp.Core.FSharpFunc`2<valuetype [FSharp.Core]Microsoft.FSharp.Control.AsyncActivation`1<int32>,class [FSharp.Core]Microsoft.FSharp.Control.AsyncReturn>::.ctor()
         IL_0006:  ldarg.0
         IL_0007:  ldarg.1
-        IL_0008:  stfld      int32 AsyncExpressionSteppingTest6/AsyncExpressionSteppingTest6/'f3@20-7'::'value'
+        IL_0008:  stfld      int32 AsyncExpressionSteppingTest6/AsyncExpressionSteppingTest6/'f3@20-5'::'value'
         IL_000d:  ret
-      } // end of method 'f3@20-7'::.ctor
+      } // end of method 'f3@20-5'::.ctor
 
       .method public strict virtual instance class [FSharp.Core]Microsoft.FSharp.Control.AsyncReturn 
               Invoke(valuetype [FSharp.Core]Microsoft.FSharp.Control.AsyncActivation`1<int32> ctxt) cil managed
       {
-        // Code size       14 (0xe)
+        // Code size       15 (0xf)
         .maxstack  8
         .line 20,20 : 17,25 ''
-        IL_0000:  ldarga.s   ctxt
-        IL_0002:  ldarg.0
-        IL_0003:  ldfld      int32 AsyncExpressionSteppingTest6/AsyncExpressionSteppingTest6/'f3@20-7'::'value'
-        IL_0008:  call       instance class [FSharp.Core]Microsoft.FSharp.Control.AsyncReturn valuetype [FSharp.Core]Microsoft.FSharp.Control.AsyncActivation`1<int32>::OnSuccess(!0)
-        IL_000d:  ret
-      } // end of method 'f3@20-7'::Invoke
+        IL_0000:  ldarg.1
+        IL_0001:  ldarg.0
+        IL_0002:  ldfld      int32 AsyncExpressionSteppingTest6/AsyncExpressionSteppingTest6/'f3@20-5'::'value'
+        IL_0007:  tail.
+        IL_0009:  call       class [FSharp.Core]Microsoft.FSharp.Control.AsyncReturn valuetype [FSharp.Core]Microsoft.FSharp.Control.AsyncActivation`1<int32>::Success(valuetype [FSharp.Core]Microsoft.FSharp.Control.AsyncActivation`1<!0>,
+                                                                                                                                                                       !0)
+        IL_000e:  ret
+      } // end of method 'f3@20-5'::Invoke
 
-    } // end of class 'f3@20-7'
+    } // end of class 'f3@20-5'
 
-    .class auto ansi serializable sealed nested assembly beforefieldinit 'f3@19-6'
+    .class auto ansi serializable sealed nested assembly beforefieldinit 'f3@19-4'
            extends class [FSharp.Core]Microsoft.FSharp.Core.FSharpFunc`2<int32,class [FSharp.Core]Microsoft.FSharp.Control.FSharpAsync`1<int32>>
     {
       .field public class [FSharp.Core]Microsoft.FSharp.Control.FSharpAsyncBuilder builder@
@@ -222,15 +226,15 @@
         IL_0001:  call       instance void class [FSharp.Core]Microsoft.FSharp.Core.FSharpFunc`2<int32,class [FSharp.Core]Microsoft.FSharp.Control.FSharpAsync`1<int32>>::.ctor()
         IL_0006:  ldarg.0
         IL_0007:  ldarg.1
-        IL_0008:  stfld      class [FSharp.Core]Microsoft.FSharp.Control.FSharpAsyncBuilder AsyncExpressionSteppingTest6/AsyncExpressionSteppingTest6/'f3@19-6'::builder@
+        IL_0008:  stfld      class [FSharp.Core]Microsoft.FSharp.Control.FSharpAsyncBuilder AsyncExpressionSteppingTest6/AsyncExpressionSteppingTest6/'f3@19-4'::builder@
         IL_000d:  ldarg.0
         IL_000e:  ldarg.2
-        IL_000f:  stfld      int32 AsyncExpressionSteppingTest6/AsyncExpressionSteppingTest6/'f3@19-6'::x1
+        IL_000f:  stfld      int32 AsyncExpressionSteppingTest6/AsyncExpressionSteppingTest6/'f3@19-4'::x1
         IL_0014:  ldarg.0
         IL_0015:  ldarg.3
-        IL_0016:  stfld      class [FSharp.Core]Microsoft.FSharp.Core.FSharpRef`1<int32> AsyncExpressionSteppingTest6/AsyncExpressionSteppingTest6/'f3@19-6'::y
+        IL_0016:  stfld      class [FSharp.Core]Microsoft.FSharp.Core.FSharpRef`1<int32> AsyncExpressionSteppingTest6/AsyncExpressionSteppingTest6/'f3@19-4'::y
         IL_001b:  ret
-      } // end of method 'f3@19-6'::.ctor
+      } // end of method 'f3@19-4'::.ctor
 
       .method public strict virtual instance class [FSharp.Core]Microsoft.FSharp.Control.FSharpAsync`1<int32> 
               Invoke(int32 _arg4) cil managed
@@ -246,9 +250,9 @@
         IL_0001:  stloc.0
         .line 19,19 : 17,37 ''
         IL_0002:  ldarg.0
-        IL_0003:  ldfld      int32 AsyncExpressionSteppingTest6/AsyncExpressionSteppingTest6/'f3@19-6'::x1
+        IL_0003:  ldfld      int32 AsyncExpressionSteppingTest6/AsyncExpressionSteppingTest6/'f3@19-4'::x1
         IL_0008:  ldarg.0
-        IL_0009:  ldfld      class [FSharp.Core]Microsoft.FSharp.Core.FSharpRef`1<int32> AsyncExpressionSteppingTest6/AsyncExpressionSteppingTest6/'f3@19-6'::y
+        IL_0009:  ldfld      class [FSharp.Core]Microsoft.FSharp.Core.FSharpRef`1<int32> AsyncExpressionSteppingTest6/AsyncExpressionSteppingTest6/'f3@19-4'::y
         IL_000e:  call       !!0 [FSharp.Core]Microsoft.FSharp.Core.Operators::op_Dereference<int32>(class [FSharp.Core]Microsoft.FSharp.Core.FSharpRef`1<!!0>)
         IL_0013:  add
         IL_0014:  ldloc.0
@@ -256,20 +260,20 @@
         IL_0016:  stloc.1
         .line 20,20 : 17,25 ''
         IL_0017:  ldarg.0
-        IL_0018:  ldfld      class [FSharp.Core]Microsoft.FSharp.Control.FSharpAsyncBuilder AsyncExpressionSteppingTest6/AsyncExpressionSteppingTest6/'f3@19-6'::builder@
+        IL_0018:  ldfld      class [FSharp.Core]Microsoft.FSharp.Control.FSharpAsyncBuilder AsyncExpressionSteppingTest6/AsyncExpressionSteppingTest6/'f3@19-4'::builder@
         IL_001d:  stloc.2
         IL_001e:  ldloc.1
         IL_001f:  stloc.3
         IL_0020:  ldloc.3
-        IL_0021:  newobj     instance void AsyncExpressionSteppingTest6/AsyncExpressionSteppingTest6/'f3@20-7'::.ctor(int32)
+        IL_0021:  newobj     instance void AsyncExpressionSteppingTest6/AsyncExpressionSteppingTest6/'f3@20-5'::.ctor(int32)
         IL_0026:  tail.
         IL_0028:  call       class [FSharp.Core]Microsoft.FSharp.Control.FSharpAsync`1<!!0> [FSharp.Core]Microsoft.FSharp.Control.AsyncPrimitives::MakeAsync<int32>(class [FSharp.Core]Microsoft.FSharp.Core.FSharpFunc`2<valuetype [FSharp.Core]Microsoft.FSharp.Control.AsyncActivation`1<!!0>,class [FSharp.Core]Microsoft.FSharp.Control.AsyncReturn>)
         IL_002d:  ret
-      } // end of method 'f3@19-6'::Invoke
+      } // end of method 'f3@19-4'::Invoke
 
-    } // end of class 'f3@19-6'
+    } // end of class 'f3@19-4'
 
-    .class auto ansi serializable sealed nested assembly beforefieldinit 'f3@18-8'
+    .class auto ansi serializable sealed nested assembly beforefieldinit 'f3@18-6'
            extends class [FSharp.Core]Microsoft.FSharp.Core.FSharpFunc`2<valuetype [FSharp.Core]Microsoft.FSharp.Control.AsyncActivation`1<int32>,class [FSharp.Core]Microsoft.FSharp.Control.AsyncReturn>
     {
       .field public class [FSharp.Core]Microsoft.FSharp.Control.FSharpAsync`1<int32> computation
@@ -292,12 +296,12 @@
         IL_0001:  call       instance void class [FSharp.Core]Microsoft.FSharp.Core.FSharpFunc`2<valuetype [FSharp.Core]Microsoft.FSharp.Control.AsyncActivation`1<int32>,class [FSharp.Core]Microsoft.FSharp.Control.AsyncReturn>::.ctor()
         IL_0006:  ldarg.0
         IL_0007:  ldarg.1
-        IL_0008:  stfld      class [FSharp.Core]Microsoft.FSharp.Control.FSharpAsync`1<int32> AsyncExpressionSteppingTest6/AsyncExpressionSteppingTest6/'f3@18-8'::computation
+        IL_0008:  stfld      class [FSharp.Core]Microsoft.FSharp.Control.FSharpAsync`1<int32> AsyncExpressionSteppingTest6/AsyncExpressionSteppingTest6/'f3@18-6'::computation
         IL_000d:  ldarg.0
         IL_000e:  ldarg.2
-        IL_000f:  stfld      class [FSharp.Core]Microsoft.FSharp.Core.FSharpFunc`2<int32,class [FSharp.Core]Microsoft.FSharp.Control.FSharpAsync`1<int32>> AsyncExpressionSteppingTest6/AsyncExpressionSteppingTest6/'f3@18-8'::binder
+        IL_000f:  stfld      class [FSharp.Core]Microsoft.FSharp.Core.FSharpFunc`2<int32,class [FSharp.Core]Microsoft.FSharp.Control.FSharpAsync`1<int32>> AsyncExpressionSteppingTest6/AsyncExpressionSteppingTest6/'f3@18-6'::binder
         IL_0014:  ret
-      } // end of method 'f3@18-8'::.ctor
+      } // end of method 'f3@18-6'::.ctor
 
       .method public strict virtual instance class [FSharp.Core]Microsoft.FSharp.Control.AsyncReturn 
               Invoke(valuetype [FSharp.Core]Microsoft.FSharp.Control.AsyncActivation`1<int32> ctxt) cil managed
@@ -307,19 +311,19 @@
         .line 18,18 : 17,31 ''
         IL_0000:  ldarg.1
         IL_0001:  ldarg.0
-        IL_0002:  ldfld      class [FSharp.Core]Microsoft.FSharp.Control.FSharpAsync`1<int32> AsyncExpressionSteppingTest6/AsyncExpressionSteppingTest6/'f3@18-8'::computation
+        IL_0002:  ldfld      class [FSharp.Core]Microsoft.FSharp.Control.FSharpAsync`1<int32> AsyncExpressionSteppingTest6/AsyncExpressionSteppingTest6/'f3@18-6'::computation
         IL_0007:  ldarg.0
-        IL_0008:  ldfld      class [FSharp.Core]Microsoft.FSharp.Core.FSharpFunc`2<int32,class [FSharp.Core]Microsoft.FSharp.Control.FSharpAsync`1<int32>> AsyncExpressionSteppingTest6/AsyncExpressionSteppingTest6/'f3@18-8'::binder
+        IL_0008:  ldfld      class [FSharp.Core]Microsoft.FSharp.Core.FSharpFunc`2<int32,class [FSharp.Core]Microsoft.FSharp.Control.FSharpAsync`1<int32>> AsyncExpressionSteppingTest6/AsyncExpressionSteppingTest6/'f3@18-6'::binder
         IL_000d:  tail.
         IL_000f:  call       class [FSharp.Core]Microsoft.FSharp.Control.AsyncReturn [FSharp.Core]Microsoft.FSharp.Control.AsyncPrimitives::Bind<int32,int32>(valuetype [FSharp.Core]Microsoft.FSharp.Control.AsyncActivation`1<!!0>,
                                                                                                                                                               class [FSharp.Core]Microsoft.FSharp.Control.FSharpAsync`1<!!1>,
                                                                                                                                                               class [FSharp.Core]Microsoft.FSharp.Core.FSharpFunc`2<!!1,class [FSharp.Core]Microsoft.FSharp.Control.FSharpAsync`1<!!0>>)
         IL_0014:  ret
-      } // end of method 'f3@18-8'::Invoke
+      } // end of method 'f3@18-6'::Invoke
 
-    } // end of class 'f3@18-8'
+    } // end of class 'f3@18-6'
 
-    .class auto ansi serializable sealed nested assembly beforefieldinit 'f3@16-5'
+    .class auto ansi serializable sealed nested assembly beforefieldinit 'f3@16-3'
            extends class [FSharp.Core]Microsoft.FSharp.Core.FSharpFunc`2<int32,class [FSharp.Core]Microsoft.FSharp.Control.FSharpAsync`1<int32>>
     {
       .field public class [FSharp.Core]Microsoft.FSharp.Control.FSharpAsyncBuilder builder@
@@ -339,12 +343,12 @@
         IL_0001:  call       instance void class [FSharp.Core]Microsoft.FSharp.Core.FSharpFunc`2<int32,class [FSharp.Core]Microsoft.FSharp.Control.FSharpAsync`1<int32>>::.ctor()
         IL_0006:  ldarg.0
         IL_0007:  ldarg.1
-        IL_0008:  stfld      class [FSharp.Core]Microsoft.FSharp.Control.FSharpAsyncBuilder AsyncExpressionSteppingTest6/AsyncExpressionSteppingTest6/'f3@16-5'::builder@
+        IL_0008:  stfld      class [FSharp.Core]Microsoft.FSharp.Control.FSharpAsyncBuilder AsyncExpressionSteppingTest6/AsyncExpressionSteppingTest6/'f3@16-3'::builder@
         IL_000d:  ldarg.0
         IL_000e:  ldarg.2
-        IL_000f:  stfld      int32 AsyncExpressionSteppingTest6/AsyncExpressionSteppingTest6/'f3@16-5'::x1
+        IL_000f:  stfld      int32 AsyncExpressionSteppingTest6/AsyncExpressionSteppingTest6/'f3@16-3'::x1
         IL_0014:  ret
-      } // end of method 'f3@16-5'::.ctor
+      } // end of method 'f3@16-3'::.ctor
 
       .method public strict virtual instance class [FSharp.Core]Microsoft.FSharp.Control.FSharpAsync`1<int32> 
               Invoke(int32 _arg3) cil managed
@@ -369,31 +373,31 @@
         IL_000f:  nop
         .line 18,18 : 17,31 ''
         IL_0010:  ldarg.0
-        IL_0011:  ldfld      class [FSharp.Core]Microsoft.FSharp.Control.FSharpAsyncBuilder AsyncExpressionSteppingTest6/AsyncExpressionSteppingTest6/'f3@16-5'::builder@
+        IL_0011:  ldfld      class [FSharp.Core]Microsoft.FSharp.Control.FSharpAsyncBuilder AsyncExpressionSteppingTest6/AsyncExpressionSteppingTest6/'f3@16-3'::builder@
         IL_0016:  stloc.2
         IL_0017:  call       class [FSharp.Core]Microsoft.FSharp.Control.FSharpAsync`1<int32> AsyncExpressionSteppingTest6/AsyncExpressionSteppingTest6::f2()
         IL_001c:  stloc.3
         IL_001d:  ldarg.0
-        IL_001e:  ldfld      class [FSharp.Core]Microsoft.FSharp.Control.FSharpAsyncBuilder AsyncExpressionSteppingTest6/AsyncExpressionSteppingTest6/'f3@16-5'::builder@
+        IL_001e:  ldfld      class [FSharp.Core]Microsoft.FSharp.Control.FSharpAsyncBuilder AsyncExpressionSteppingTest6/AsyncExpressionSteppingTest6/'f3@16-3'::builder@
         IL_0023:  ldarg.0
-        IL_0024:  ldfld      int32 AsyncExpressionSteppingTest6/AsyncExpressionSteppingTest6/'f3@16-5'::x1
+        IL_0024:  ldfld      int32 AsyncExpressionSteppingTest6/AsyncExpressionSteppingTest6/'f3@16-3'::x1
         IL_0029:  ldloc.1
-        IL_002a:  newobj     instance void AsyncExpressionSteppingTest6/AsyncExpressionSteppingTest6/'f3@19-6'::.ctor(class [FSharp.Core]Microsoft.FSharp.Control.FSharpAsyncBuilder,
+        IL_002a:  newobj     instance void AsyncExpressionSteppingTest6/AsyncExpressionSteppingTest6/'f3@19-4'::.ctor(class [FSharp.Core]Microsoft.FSharp.Control.FSharpAsyncBuilder,
                                                                                                                       int32,
                                                                                                                       class [FSharp.Core]Microsoft.FSharp.Core.FSharpRef`1<int32>)
         IL_002f:  stloc.s    V_4
         IL_0031:  ldloc.3
         IL_0032:  ldloc.s    V_4
-        IL_0034:  newobj     instance void AsyncExpressionSteppingTest6/AsyncExpressionSteppingTest6/'f3@18-8'::.ctor(class [FSharp.Core]Microsoft.FSharp.Control.FSharpAsync`1<int32>,
+        IL_0034:  newobj     instance void AsyncExpressionSteppingTest6/AsyncExpressionSteppingTest6/'f3@18-6'::.ctor(class [FSharp.Core]Microsoft.FSharp.Control.FSharpAsync`1<int32>,
                                                                                                                       class [FSharp.Core]Microsoft.FSharp.Core.FSharpFunc`2<int32,class [FSharp.Core]Microsoft.FSharp.Control.FSharpAsync`1<int32>>)
         IL_0039:  tail.
         IL_003b:  call       class [FSharp.Core]Microsoft.FSharp.Control.FSharpAsync`1<!!0> [FSharp.Core]Microsoft.FSharp.Control.AsyncPrimitives::MakeAsync<int32>(class [FSharp.Core]Microsoft.FSharp.Core.FSharpFunc`2<valuetype [FSharp.Core]Microsoft.FSharp.Control.AsyncActivation`1<!!0>,class [FSharp.Core]Microsoft.FSharp.Control.AsyncReturn>)
         IL_0040:  ret
-      } // end of method 'f3@16-5'::Invoke
+      } // end of method 'f3@16-3'::Invoke
 
-    } // end of class 'f3@16-5'
+    } // end of class 'f3@16-3'
 
-    .class auto ansi serializable sealed nested assembly beforefieldinit 'f3@15-9'
+    .class auto ansi serializable sealed nested assembly beforefieldinit 'f3@15-7'
            extends class [FSharp.Core]Microsoft.FSharp.Core.FSharpFunc`2<valuetype [FSharp.Core]Microsoft.FSharp.Control.AsyncActivation`1<int32>,class [FSharp.Core]Microsoft.FSharp.Control.AsyncReturn>
     {
       .field public class [FSharp.Core]Microsoft.FSharp.Control.FSharpAsync`1<int32> computation
@@ -416,12 +420,12 @@
         IL_0001:  call       instance void class [FSharp.Core]Microsoft.FSharp.Core.FSharpFunc`2<valuetype [FSharp.Core]Microsoft.FSharp.Control.AsyncActivation`1<int32>,class [FSharp.Core]Microsoft.FSharp.Control.AsyncReturn>::.ctor()
         IL_0006:  ldarg.0
         IL_0007:  ldarg.1
-        IL_0008:  stfld      class [FSharp.Core]Microsoft.FSharp.Control.FSharpAsync`1<int32> AsyncExpressionSteppingTest6/AsyncExpressionSteppingTest6/'f3@15-9'::computation
+        IL_0008:  stfld      class [FSharp.Core]Microsoft.FSharp.Control.FSharpAsync`1<int32> AsyncExpressionSteppingTest6/AsyncExpressionSteppingTest6/'f3@15-7'::computation
         IL_000d:  ldarg.0
         IL_000e:  ldarg.2
-        IL_000f:  stfld      class [FSharp.Core]Microsoft.FSharp.Core.FSharpFunc`2<int32,class [FSharp.Core]Microsoft.FSharp.Control.FSharpAsync`1<int32>> AsyncExpressionSteppingTest6/AsyncExpressionSteppingTest6/'f3@15-9'::binder
+        IL_000f:  stfld      class [FSharp.Core]Microsoft.FSharp.Core.FSharpFunc`2<int32,class [FSharp.Core]Microsoft.FSharp.Control.FSharpAsync`1<int32>> AsyncExpressionSteppingTest6/AsyncExpressionSteppingTest6/'f3@15-7'::binder
         IL_0014:  ret
-      } // end of method 'f3@15-9'::.ctor
+      } // end of method 'f3@15-7'::.ctor
 
       .method public strict virtual instance class [FSharp.Core]Microsoft.FSharp.Control.AsyncReturn 
               Invoke(valuetype [FSharp.Core]Microsoft.FSharp.Control.AsyncActivation`1<int32> ctxt) cil managed
@@ -431,19 +435,19 @@
         .line 15,15 : 17,31 ''
         IL_0000:  ldarg.1
         IL_0001:  ldarg.0
-        IL_0002:  ldfld      class [FSharp.Core]Microsoft.FSharp.Control.FSharpAsync`1<int32> AsyncExpressionSteppingTest6/AsyncExpressionSteppingTest6/'f3@15-9'::computation
+        IL_0002:  ldfld      class [FSharp.Core]Microsoft.FSharp.Control.FSharpAsync`1<int32> AsyncExpressionSteppingTest6/AsyncExpressionSteppingTest6/'f3@15-7'::computation
         IL_0007:  ldarg.0
-        IL_0008:  ldfld      class [FSharp.Core]Microsoft.FSharp.Core.FSharpFunc`2<int32,class [FSharp.Core]Microsoft.FSharp.Control.FSharpAsync`1<int32>> AsyncExpressionSteppingTest6/AsyncExpressionSteppingTest6/'f3@15-9'::binder
+        IL_0008:  ldfld      class [FSharp.Core]Microsoft.FSharp.Core.FSharpFunc`2<int32,class [FSharp.Core]Microsoft.FSharp.Control.FSharpAsync`1<int32>> AsyncExpressionSteppingTest6/AsyncExpressionSteppingTest6/'f3@15-7'::binder
         IL_000d:  tail.
         IL_000f:  call       class [FSharp.Core]Microsoft.FSharp.Control.AsyncReturn [FSharp.Core]Microsoft.FSharp.Control.AsyncPrimitives::Bind<int32,int32>(valuetype [FSharp.Core]Microsoft.FSharp.Control.AsyncActivation`1<!!0>,
                                                                                                                                                               class [FSharp.Core]Microsoft.FSharp.Control.FSharpAsync`1<!!1>,
                                                                                                                                                               class [FSharp.Core]Microsoft.FSharp.Core.FSharpFunc`2<!!1,class [FSharp.Core]Microsoft.FSharp.Control.FSharpAsync`1<!!0>>)
         IL_0014:  ret
-      } // end of method 'f3@15-9'::Invoke
+      } // end of method 'f3@15-7'::Invoke
 
-    } // end of class 'f3@15-9'
+    } // end of class 'f3@15-7'
 
-    .class auto ansi serializable sealed nested assembly beforefieldinit 'f3@15-4'
+    .class auto ansi serializable sealed nested assembly beforefieldinit 'f3@15-2'
            extends class [FSharp.Core]Microsoft.FSharp.Core.FSharpFunc`2<int32,class [FSharp.Core]Microsoft.FSharp.Control.FSharpAsync`1<int32>>
     {
       .field public class [FSharp.Core]Microsoft.FSharp.Control.FSharpAsyncBuilder builder@
@@ -463,12 +467,12 @@
         IL_0001:  call       instance void class [FSharp.Core]Microsoft.FSharp.Core.FSharpFunc`2<int32,class [FSharp.Core]Microsoft.FSharp.Control.FSharpAsync`1<int32>>::.ctor()
         IL_0006:  ldarg.0
         IL_0007:  ldarg.1
-        IL_0008:  stfld      class [FSharp.Core]Microsoft.FSharp.Control.FSharpAsyncBuilder AsyncExpressionSteppingTest6/AsyncExpressionSteppingTest6/'f3@15-4'::builder@
+        IL_0008:  stfld      class [FSharp.Core]Microsoft.FSharp.Control.FSharpAsyncBuilder AsyncExpressionSteppingTest6/AsyncExpressionSteppingTest6/'f3@15-2'::builder@
         IL_000d:  ldarg.0
         IL_000e:  ldarg.2
-        IL_000f:  stfld      int32 AsyncExpressionSteppingTest6/AsyncExpressionSteppingTest6/'f3@15-4'::x1
+        IL_000f:  stfld      int32 AsyncExpressionSteppingTest6/AsyncExpressionSteppingTest6/'f3@15-2'::x1
         IL_0014:  ret
-      } // end of method 'f3@15-4'::.ctor
+      } // end of method 'f3@15-2'::.ctor
 
       .method public strict virtual instance class [FSharp.Core]Microsoft.FSharp.Control.FSharpAsync`1<int32> 
               Invoke(int32 _arg2) cil managed
@@ -484,29 +488,29 @@
         IL_0001:  stloc.0
         .line 15,15 : 17,31 ''
         IL_0002:  ldarg.0
-        IL_0003:  ldfld      class [FSharp.Core]Microsoft.FSharp.Control.FSharpAsyncBuilder AsyncExpressionSteppingTest6/AsyncExpressionSteppingTest6/'f3@15-4'::builder@
+        IL_0003:  ldfld      class [FSharp.Core]Microsoft.FSharp.Control.FSharpAsyncBuilder AsyncExpressionSteppingTest6/AsyncExpressionSteppingTest6/'f3@15-2'::builder@
         IL_0008:  stloc.1
         IL_0009:  call       class [FSharp.Core]Microsoft.FSharp.Control.FSharpAsync`1<int32> AsyncExpressionSteppingTest6/AsyncExpressionSteppingTest6::f2()
         IL_000e:  stloc.2
         IL_000f:  ldarg.0
-        IL_0010:  ldfld      class [FSharp.Core]Microsoft.FSharp.Control.FSharpAsyncBuilder AsyncExpressionSteppingTest6/AsyncExpressionSteppingTest6/'f3@15-4'::builder@
+        IL_0010:  ldfld      class [FSharp.Core]Microsoft.FSharp.Control.FSharpAsyncBuilder AsyncExpressionSteppingTest6/AsyncExpressionSteppingTest6/'f3@15-2'::builder@
         IL_0015:  ldarg.0
-        IL_0016:  ldfld      int32 AsyncExpressionSteppingTest6/AsyncExpressionSteppingTest6/'f3@15-4'::x1
-        IL_001b:  newobj     instance void AsyncExpressionSteppingTest6/AsyncExpressionSteppingTest6/'f3@16-5'::.ctor(class [FSharp.Core]Microsoft.FSharp.Control.FSharpAsyncBuilder,
+        IL_0016:  ldfld      int32 AsyncExpressionSteppingTest6/AsyncExpressionSteppingTest6/'f3@15-2'::x1
+        IL_001b:  newobj     instance void AsyncExpressionSteppingTest6/AsyncExpressionSteppingTest6/'f3@16-3'::.ctor(class [FSharp.Core]Microsoft.FSharp.Control.FSharpAsyncBuilder,
                                                                                                                       int32)
         IL_0020:  stloc.3
         IL_0021:  ldloc.2
         IL_0022:  ldloc.3
-        IL_0023:  newobj     instance void AsyncExpressionSteppingTest6/AsyncExpressionSteppingTest6/'f3@15-9'::.ctor(class [FSharp.Core]Microsoft.FSharp.Control.FSharpAsync`1<int32>,
+        IL_0023:  newobj     instance void AsyncExpressionSteppingTest6/AsyncExpressionSteppingTest6/'f3@15-7'::.ctor(class [FSharp.Core]Microsoft.FSharp.Control.FSharpAsync`1<int32>,
                                                                                                                       class [FSharp.Core]Microsoft.FSharp.Core.FSharpFunc`2<int32,class [FSharp.Core]Microsoft.FSharp.Control.FSharpAsync`1<int32>>)
         IL_0028:  tail.
         IL_002a:  call       class [FSharp.Core]Microsoft.FSharp.Control.FSharpAsync`1<!!0> [FSharp.Core]Microsoft.FSharp.Control.AsyncPrimitives::MakeAsync<int32>(class [FSharp.Core]Microsoft.FSharp.Core.FSharpFunc`2<valuetype [FSharp.Core]Microsoft.FSharp.Control.AsyncActivation`1<!!0>,class [FSharp.Core]Microsoft.FSharp.Control.AsyncReturn>)
         IL_002f:  ret
-      } // end of method 'f3@15-4'::Invoke
+      } // end of method 'f3@15-2'::Invoke
 
-    } // end of class 'f3@15-4'
+    } // end of class 'f3@15-2'
 
-    .class auto ansi serializable sealed nested assembly beforefieldinit 'f3@14-10'
+    .class auto ansi serializable sealed nested assembly beforefieldinit 'f3@14-8'
            extends class [FSharp.Core]Microsoft.FSharp.Core.FSharpFunc`2<valuetype [FSharp.Core]Microsoft.FSharp.Control.AsyncActivation`1<int32>,class [FSharp.Core]Microsoft.FSharp.Control.AsyncReturn>
     {
       .field public class [FSharp.Core]Microsoft.FSharp.Control.FSharpAsync`1<int32> computation
@@ -529,12 +533,12 @@
         IL_0001:  call       instance void class [FSharp.Core]Microsoft.FSharp.Core.FSharpFunc`2<valuetype [FSharp.Core]Microsoft.FSharp.Control.AsyncActivation`1<int32>,class [FSharp.Core]Microsoft.FSharp.Control.AsyncReturn>::.ctor()
         IL_0006:  ldarg.0
         IL_0007:  ldarg.1
-        IL_0008:  stfld      class [FSharp.Core]Microsoft.FSharp.Control.FSharpAsync`1<int32> AsyncExpressionSteppingTest6/AsyncExpressionSteppingTest6/'f3@14-10'::computation
+        IL_0008:  stfld      class [FSharp.Core]Microsoft.FSharp.Control.FSharpAsync`1<int32> AsyncExpressionSteppingTest6/AsyncExpressionSteppingTest6/'f3@14-8'::computation
         IL_000d:  ldarg.0
         IL_000e:  ldarg.2
-        IL_000f:  stfld      class [FSharp.Core]Microsoft.FSharp.Core.FSharpFunc`2<int32,class [FSharp.Core]Microsoft.FSharp.Control.FSharpAsync`1<int32>> AsyncExpressionSteppingTest6/AsyncExpressionSteppingTest6/'f3@14-10'::binder
+        IL_000f:  stfld      class [FSharp.Core]Microsoft.FSharp.Core.FSharpFunc`2<int32,class [FSharp.Core]Microsoft.FSharp.Control.FSharpAsync`1<int32>> AsyncExpressionSteppingTest6/AsyncExpressionSteppingTest6/'f3@14-8'::binder
         IL_0014:  ret
-      } // end of method 'f3@14-10'::.ctor
+      } // end of method 'f3@14-8'::.ctor
 
       .method public strict virtual instance class [FSharp.Core]Microsoft.FSharp.Control.AsyncReturn 
               Invoke(valuetype [FSharp.Core]Microsoft.FSharp.Control.AsyncActivation`1<int32> ctxt) cil managed
@@ -544,19 +548,19 @@
         .line 14,14 : 17,31 ''
         IL_0000:  ldarg.1
         IL_0001:  ldarg.0
-        IL_0002:  ldfld      class [FSharp.Core]Microsoft.FSharp.Control.FSharpAsync`1<int32> AsyncExpressionSteppingTest6/AsyncExpressionSteppingTest6/'f3@14-10'::computation
+        IL_0002:  ldfld      class [FSharp.Core]Microsoft.FSharp.Control.FSharpAsync`1<int32> AsyncExpressionSteppingTest6/AsyncExpressionSteppingTest6/'f3@14-8'::computation
         IL_0007:  ldarg.0
-        IL_0008:  ldfld      class [FSharp.Core]Microsoft.FSharp.Core.FSharpFunc`2<int32,class [FSharp.Core]Microsoft.FSharp.Control.FSharpAsync`1<int32>> AsyncExpressionSteppingTest6/AsyncExpressionSteppingTest6/'f3@14-10'::binder
+        IL_0008:  ldfld      class [FSharp.Core]Microsoft.FSharp.Core.FSharpFunc`2<int32,class [FSharp.Core]Microsoft.FSharp.Control.FSharpAsync`1<int32>> AsyncExpressionSteppingTest6/AsyncExpressionSteppingTest6/'f3@14-8'::binder
         IL_000d:  tail.
         IL_000f:  call       class [FSharp.Core]Microsoft.FSharp.Control.AsyncReturn [FSharp.Core]Microsoft.FSharp.Control.AsyncPrimitives::Bind<int32,int32>(valuetype [FSharp.Core]Microsoft.FSharp.Control.AsyncActivation`1<!!0>,
                                                                                                                                                               class [FSharp.Core]Microsoft.FSharp.Control.FSharpAsync`1<!!1>,
                                                                                                                                                               class [FSharp.Core]Microsoft.FSharp.Core.FSharpFunc`2<!!1,class [FSharp.Core]Microsoft.FSharp.Control.FSharpAsync`1<!!0>>)
         IL_0014:  ret
-      } // end of method 'f3@14-10'::Invoke
+      } // end of method 'f3@14-8'::Invoke
 
-    } // end of class 'f3@14-10'
+    } // end of class 'f3@14-8'
 
-    .class auto ansi serializable sealed nested assembly beforefieldinit 'f3@14-3'
+    .class auto ansi serializable sealed nested assembly beforefieldinit 'f3@14-1'
            extends class [FSharp.Core]Microsoft.FSharp.Core.FSharpFunc`2<int32,class [FSharp.Core]Microsoft.FSharp.Control.FSharpAsync`1<int32>>
     {
       .field public class [FSharp.Core]Microsoft.FSharp.Control.FSharpAsyncBuilder builder@
@@ -574,9 +578,9 @@
         IL_0001:  call       instance void class [FSharp.Core]Microsoft.FSharp.Core.FSharpFunc`2<int32,class [FSharp.Core]Microsoft.FSharp.Control.FSharpAsync`1<int32>>::.ctor()
         IL_0006:  ldarg.0
         IL_0007:  ldarg.1
-        IL_0008:  stfld      class [FSharp.Core]Microsoft.FSharp.Control.FSharpAsyncBuilder AsyncExpressionSteppingTest6/AsyncExpressionSteppingTest6/'f3@14-3'::builder@
+        IL_0008:  stfld      class [FSharp.Core]Microsoft.FSharp.Control.FSharpAsyncBuilder AsyncExpressionSteppingTest6/AsyncExpressionSteppingTest6/'f3@14-1'::builder@
         IL_000d:  ret
-      } // end of method 'f3@14-3'::.ctor
+      } // end of method 'f3@14-1'::.ctor
 
       .method public strict virtual instance class [FSharp.Core]Microsoft.FSharp.Control.FSharpAsync`1<int32> 
               Invoke(int32 _arg1) cil managed
@@ -592,28 +596,28 @@
         IL_0001:  stloc.0
         .line 14,14 : 17,31 ''
         IL_0002:  ldarg.0
-        IL_0003:  ldfld      class [FSharp.Core]Microsoft.FSharp.Control.FSharpAsyncBuilder AsyncExpressionSteppingTest6/AsyncExpressionSteppingTest6/'f3@14-3'::builder@
+        IL_0003:  ldfld      class [FSharp.Core]Microsoft.FSharp.Control.FSharpAsyncBuilder AsyncExpressionSteppingTest6/AsyncExpressionSteppingTest6/'f3@14-1'::builder@
         IL_0008:  stloc.1
         IL_0009:  call       class [FSharp.Core]Microsoft.FSharp.Control.FSharpAsync`1<int32> AsyncExpressionSteppingTest6/AsyncExpressionSteppingTest6::f2()
         IL_000e:  stloc.2
         IL_000f:  ldarg.0
-        IL_0010:  ldfld      class [FSharp.Core]Microsoft.FSharp.Control.FSharpAsyncBuilder AsyncExpressionSteppingTest6/AsyncExpressionSteppingTest6/'f3@14-3'::builder@
+        IL_0010:  ldfld      class [FSharp.Core]Microsoft.FSharp.Control.FSharpAsyncBuilder AsyncExpressionSteppingTest6/AsyncExpressionSteppingTest6/'f3@14-1'::builder@
         IL_0015:  ldloc.0
-        IL_0016:  newobj     instance void AsyncExpressionSteppingTest6/AsyncExpressionSteppingTest6/'f3@15-4'::.ctor(class [FSharp.Core]Microsoft.FSharp.Control.FSharpAsyncBuilder,
+        IL_0016:  newobj     instance void AsyncExpressionSteppingTest6/AsyncExpressionSteppingTest6/'f3@15-2'::.ctor(class [FSharp.Core]Microsoft.FSharp.Control.FSharpAsyncBuilder,
                                                                                                                       int32)
         IL_001b:  stloc.3
         IL_001c:  ldloc.2
         IL_001d:  ldloc.3
-        IL_001e:  newobj     instance void AsyncExpressionSteppingTest6/AsyncExpressionSteppingTest6/'f3@14-10'::.ctor(class [FSharp.Core]Microsoft.FSharp.Control.FSharpAsync`1<int32>,
-                                                                                                                       class [FSharp.Core]Microsoft.FSharp.Core.FSharpFunc`2<int32,class [FSharp.Core]Microsoft.FSharp.Control.FSharpAsync`1<int32>>)
+        IL_001e:  newobj     instance void AsyncExpressionSteppingTest6/AsyncExpressionSteppingTest6/'f3@14-8'::.ctor(class [FSharp.Core]Microsoft.FSharp.Control.FSharpAsync`1<int32>,
+                                                                                                                      class [FSharp.Core]Microsoft.FSharp.Core.FSharpFunc`2<int32,class [FSharp.Core]Microsoft.FSharp.Control.FSharpAsync`1<int32>>)
         IL_0023:  tail.
         IL_0025:  call       class [FSharp.Core]Microsoft.FSharp.Control.FSharpAsync`1<!!0> [FSharp.Core]Microsoft.FSharp.Control.AsyncPrimitives::MakeAsync<int32>(class [FSharp.Core]Microsoft.FSharp.Core.FSharpFunc`2<valuetype [FSharp.Core]Microsoft.FSharp.Control.AsyncActivation`1<!!0>,class [FSharp.Core]Microsoft.FSharp.Control.AsyncReturn>)
         IL_002a:  ret
-      } // end of method 'f3@14-3'::Invoke
+      } // end of method 'f3@14-1'::Invoke
 
-    } // end of class 'f3@14-3'
+    } // end of class 'f3@14-1'
 
-    .class auto ansi serializable sealed nested assembly beforefieldinit 'f3@13-11'
+    .class auto ansi serializable sealed nested assembly beforefieldinit 'f3@13-9'
            extends class [FSharp.Core]Microsoft.FSharp.Core.FSharpFunc`2<valuetype [FSharp.Core]Microsoft.FSharp.Control.AsyncActivation`1<int32>,class [FSharp.Core]Microsoft.FSharp.Control.AsyncReturn>
     {
       .field public class [FSharp.Core]Microsoft.FSharp.Control.FSharpAsync`1<int32> computation
@@ -636,12 +640,12 @@
         IL_0001:  call       instance void class [FSharp.Core]Microsoft.FSharp.Core.FSharpFunc`2<valuetype [FSharp.Core]Microsoft.FSharp.Control.AsyncActivation`1<int32>,class [FSharp.Core]Microsoft.FSharp.Control.AsyncReturn>::.ctor()
         IL_0006:  ldarg.0
         IL_0007:  ldarg.1
-        IL_0008:  stfld      class [FSharp.Core]Microsoft.FSharp.Control.FSharpAsync`1<int32> AsyncExpressionSteppingTest6/AsyncExpressionSteppingTest6/'f3@13-11'::computation
+        IL_0008:  stfld      class [FSharp.Core]Microsoft.FSharp.Control.FSharpAsync`1<int32> AsyncExpressionSteppingTest6/AsyncExpressionSteppingTest6/'f3@13-9'::computation
         IL_000d:  ldarg.0
         IL_000e:  ldarg.2
-        IL_000f:  stfld      class [FSharp.Core]Microsoft.FSharp.Core.FSharpFunc`2<int32,class [FSharp.Core]Microsoft.FSharp.Control.FSharpAsync`1<int32>> AsyncExpressionSteppingTest6/AsyncExpressionSteppingTest6/'f3@13-11'::binder
+        IL_000f:  stfld      class [FSharp.Core]Microsoft.FSharp.Core.FSharpFunc`2<int32,class [FSharp.Core]Microsoft.FSharp.Control.FSharpAsync`1<int32>> AsyncExpressionSteppingTest6/AsyncExpressionSteppingTest6/'f3@13-9'::binder
         IL_0014:  ret
-      } // end of method 'f3@13-11'::.ctor
+      } // end of method 'f3@13-9'::.ctor
 
       .method public strict virtual instance class [FSharp.Core]Microsoft.FSharp.Control.AsyncReturn 
               Invoke(valuetype [FSharp.Core]Microsoft.FSharp.Control.AsyncActivation`1<int32> ctxt) cil managed
@@ -651,19 +655,19 @@
         .line 13,13 : 17,31 ''
         IL_0000:  ldarg.1
         IL_0001:  ldarg.0
-        IL_0002:  ldfld      class [FSharp.Core]Microsoft.FSharp.Control.FSharpAsync`1<int32> AsyncExpressionSteppingTest6/AsyncExpressionSteppingTest6/'f3@13-11'::computation
+        IL_0002:  ldfld      class [FSharp.Core]Microsoft.FSharp.Control.FSharpAsync`1<int32> AsyncExpressionSteppingTest6/AsyncExpressionSteppingTest6/'f3@13-9'::computation
         IL_0007:  ldarg.0
-        IL_0008:  ldfld      class [FSharp.Core]Microsoft.FSharp.Core.FSharpFunc`2<int32,class [FSharp.Core]Microsoft.FSharp.Control.FSharpAsync`1<int32>> AsyncExpressionSteppingTest6/AsyncExpressionSteppingTest6/'f3@13-11'::binder
+        IL_0008:  ldfld      class [FSharp.Core]Microsoft.FSharp.Core.FSharpFunc`2<int32,class [FSharp.Core]Microsoft.FSharp.Control.FSharpAsync`1<int32>> AsyncExpressionSteppingTest6/AsyncExpressionSteppingTest6/'f3@13-9'::binder
         IL_000d:  tail.
         IL_000f:  call       class [FSharp.Core]Microsoft.FSharp.Control.AsyncReturn [FSharp.Core]Microsoft.FSharp.Control.AsyncPrimitives::Bind<int32,int32>(valuetype [FSharp.Core]Microsoft.FSharp.Control.AsyncActivation`1<!!0>,
                                                                                                                                                               class [FSharp.Core]Microsoft.FSharp.Control.FSharpAsync`1<!!1>,
                                                                                                                                                               class [FSharp.Core]Microsoft.FSharp.Core.FSharpFunc`2<!!1,class [FSharp.Core]Microsoft.FSharp.Control.FSharpAsync`1<!!0>>)
         IL_0014:  ret
-      } // end of method 'f3@13-11'::Invoke
+      } // end of method 'f3@13-9'::Invoke
 
-    } // end of class 'f3@13-11'
+    } // end of class 'f3@13-9'
 
-    .class auto ansi serializable sealed nested assembly beforefieldinit 'f3@13-2'
+    .class auto ansi serializable sealed nested assembly beforefieldinit f3@13
            extends class [FSharp.Core]Microsoft.FSharp.Core.FSharpFunc`2<class [FSharp.Core]Microsoft.FSharp.Core.Unit,class [FSharp.Core]Microsoft.FSharp.Control.FSharpAsync`1<int32>>
     {
       .field public class [FSharp.Core]Microsoft.FSharp.Control.FSharpAsyncBuilder builder@
@@ -681,9 +685,9 @@
         IL_0001:  call       instance void class [FSharp.Core]Microsoft.FSharp.Core.FSharpFunc`2<class [FSharp.Core]Microsoft.FSharp.Core.Unit,class [FSharp.Core]Microsoft.FSharp.Control.FSharpAsync`1<int32>>::.ctor()
         IL_0006:  ldarg.0
         IL_0007:  ldarg.1
-        IL_0008:  stfld      class [FSharp.Core]Microsoft.FSharp.Control.FSharpAsyncBuilder AsyncExpressionSteppingTest6/AsyncExpressionSteppingTest6/'f3@13-2'::builder@
+        IL_0008:  stfld      class [FSharp.Core]Microsoft.FSharp.Control.FSharpAsyncBuilder AsyncExpressionSteppingTest6/AsyncExpressionSteppingTest6/f3@13::builder@
         IL_000d:  ret
-      } // end of method 'f3@13-2'::.ctor
+      } // end of method f3@13::.ctor
 
       .method public strict virtual instance class [FSharp.Core]Microsoft.FSharp.Control.FSharpAsync`1<int32> 
               Invoke(class [FSharp.Core]Microsoft.FSharp.Core.Unit unitVar) cil managed
@@ -695,24 +699,24 @@
                  [2] class [FSharp.Core]Microsoft.FSharp.Core.FSharpFunc`2<int32,class [FSharp.Core]Microsoft.FSharp.Control.FSharpAsync`1<int32>> V_2)
         .line 13,13 : 17,31 ''
         IL_0000:  ldarg.0
-        IL_0001:  ldfld      class [FSharp.Core]Microsoft.FSharp.Control.FSharpAsyncBuilder AsyncExpressionSteppingTest6/AsyncExpressionSteppingTest6/'f3@13-2'::builder@
+        IL_0001:  ldfld      class [FSharp.Core]Microsoft.FSharp.Control.FSharpAsyncBuilder AsyncExpressionSteppingTest6/AsyncExpressionSteppingTest6/f3@13::builder@
         IL_0006:  stloc.0
         IL_0007:  call       class [FSharp.Core]Microsoft.FSharp.Control.FSharpAsync`1<int32> AsyncExpressionSteppingTest6/AsyncExpressionSteppingTest6::f2()
         IL_000c:  stloc.1
         IL_000d:  ldarg.0
-        IL_000e:  ldfld      class [FSharp.Core]Microsoft.FSharp.Control.FSharpAsyncBuilder AsyncExpressionSteppingTest6/AsyncExpressionSteppingTest6/'f3@13-2'::builder@
-        IL_0013:  newobj     instance void AsyncExpressionSteppingTest6/AsyncExpressionSteppingTest6/'f3@14-3'::.ctor(class [FSharp.Core]Microsoft.FSharp.Control.FSharpAsyncBuilder)
+        IL_000e:  ldfld      class [FSharp.Core]Microsoft.FSharp.Control.FSharpAsyncBuilder AsyncExpressionSteppingTest6/AsyncExpressionSteppingTest6/f3@13::builder@
+        IL_0013:  newobj     instance void AsyncExpressionSteppingTest6/AsyncExpressionSteppingTest6/'f3@14-1'::.ctor(class [FSharp.Core]Microsoft.FSharp.Control.FSharpAsyncBuilder)
         IL_0018:  stloc.2
         IL_0019:  ldloc.1
         IL_001a:  ldloc.2
-        IL_001b:  newobj     instance void AsyncExpressionSteppingTest6/AsyncExpressionSteppingTest6/'f3@13-11'::.ctor(class [FSharp.Core]Microsoft.FSharp.Control.FSharpAsync`1<int32>,
-                                                                                                                       class [FSharp.Core]Microsoft.FSharp.Core.FSharpFunc`2<int32,class [FSharp.Core]Microsoft.FSharp.Control.FSharpAsync`1<int32>>)
+        IL_001b:  newobj     instance void AsyncExpressionSteppingTest6/AsyncExpressionSteppingTest6/'f3@13-9'::.ctor(class [FSharp.Core]Microsoft.FSharp.Control.FSharpAsync`1<int32>,
+                                                                                                                      class [FSharp.Core]Microsoft.FSharp.Core.FSharpFunc`2<int32,class [FSharp.Core]Microsoft.FSharp.Control.FSharpAsync`1<int32>>)
         IL_0020:  tail.
         IL_0022:  call       class [FSharp.Core]Microsoft.FSharp.Control.FSharpAsync`1<!!0> [FSharp.Core]Microsoft.FSharp.Control.AsyncPrimitives::MakeAsync<int32>(class [FSharp.Core]Microsoft.FSharp.Core.FSharpFunc`2<valuetype [FSharp.Core]Microsoft.FSharp.Control.AsyncActivation`1<!!0>,class [FSharp.Core]Microsoft.FSharp.Control.AsyncReturn>)
         IL_0027:  ret
-      } // end of method 'f3@13-2'::Invoke
+      } // end of method f3@13::Invoke
 
-    } // end of class 'f3@13-2'
+    } // end of class f3@13
 
     .method public static class [FSharp.Core]Microsoft.FSharp.Control.FSharpAsync`1<int32> 
             f2() cil managed
@@ -725,7 +729,7 @@
       IL_0005:  stloc.0
       IL_0006:  ldloc.0
       IL_0007:  ldloc.0
-      IL_0008:  newobj     instance void AsyncExpressionSteppingTest6/AsyncExpressionSteppingTest6/'f2@5-3'::.ctor(class [FSharp.Core]Microsoft.FSharp.Control.FSharpAsyncBuilder)
+      IL_0008:  newobj     instance void AsyncExpressionSteppingTest6/AsyncExpressionSteppingTest6/f2@5::.ctor(class [FSharp.Core]Microsoft.FSharp.Control.FSharpAsyncBuilder)
       IL_000d:  tail.
       IL_000f:  callvirt   instance class [FSharp.Core]Microsoft.FSharp.Control.FSharpAsync`1<!!0> [FSharp.Core]Microsoft.FSharp.Control.FSharpAsyncBuilder::Delay<int32>(class [FSharp.Core]Microsoft.FSharp.Core.FSharpFunc`2<class [FSharp.Core]Microsoft.FSharp.Core.Unit,class [FSharp.Core]Microsoft.FSharp.Control.FSharpAsync`1<!!0>>)
       IL_0014:  ret
@@ -742,7 +746,7 @@
       IL_0005:  stloc.0
       IL_0006:  ldloc.0
       IL_0007:  ldloc.0
-      IL_0008:  newobj     instance void AsyncExpressionSteppingTest6/AsyncExpressionSteppingTest6/'f3@13-2'::.ctor(class [FSharp.Core]Microsoft.FSharp.Control.FSharpAsyncBuilder)
+      IL_0008:  newobj     instance void AsyncExpressionSteppingTest6/AsyncExpressionSteppingTest6/f3@13::.ctor(class [FSharp.Core]Microsoft.FSharp.Control.FSharpAsyncBuilder)
       IL_000d:  tail.
       IL_000f:  callvirt   instance class [FSharp.Core]Microsoft.FSharp.Control.FSharpAsync`1<!!0> [FSharp.Core]Microsoft.FSharp.Control.FSharpAsyncBuilder::Delay<int32>(class [FSharp.Core]Microsoft.FSharp.Core.FSharpFunc`2<class [FSharp.Core]Microsoft.FSharp.Core.Unit,class [FSharp.Core]Microsoft.FSharp.Control.FSharpAsync`1<!!0>>)
       IL_0014:  ret