Fix ValueTask.tryWith

Author: gusty

src/FSharpPlus/Extensions/ValueTask.fs

@@ -282,24 +282,33 @@ module ValueTask =
         let unwrapException (agg: AggregateException) =
             if agg.InnerExceptions.Count = 1 then agg.InnerExceptions.[0]
             else agg :> Exception
-        try
-            let task = body ()
-            if task.IsCompleted then
-                match task with
-                | Succeeded _ -> task
-                | Faulted exn -> compensation (unwrapException exn)
-                | Canceled    -> compensation (TaskCanceledException ())
-            else
-                let tcs = TaskCompletionSource<'T> ()
-                let f = function
-                    | Succeeded r -> tcs.SetResult r
-                    | Faulted exn -> continueTask tcs (compensation (unwrapException exn))      (fun r -> try tcs.SetResult r with e -> tcs.SetException e)
-                    | Canceled    -> continueTask tcs (compensation (TaskCanceledException ())) (fun r -> try tcs.SetResult r with e -> tcs.SetException e)
-                task.ConfigureAwait(false).GetAwaiter().UnsafeOnCompleted (fun () -> f task)
-                ValueTask<'T> tcs.Task
-        with
-        | :? AggregateException as exn -> compensation (unwrapException exn)
-        | exn                          -> compensation exn
+        
+        let mutable ran = false
+        
+        let compensation exn =
+            if not ran then ran <- true
+            try compensation exn
+            with e -> raise e
+
+        let task = 
+            try body ()
+            with
+            | :? AggregateException as aex -> compensation (unwrapException aex)
+            | exn                          -> compensation exn
+        if ran then task
+        elif task.IsCompleted then
+            match task with
+            | Succeeded _ -> task
+            | Faulted aex -> compensation (unwrapException aex)
+            | Canceled    -> compensation (TaskCanceledException ())
+        else
+            let tcs = TaskCompletionSource<'T> ()
+            let f = function
+                | Succeeded r -> tcs.SetResult r
+                | Faulted aex -> continueTask tcs (compensation (unwrapException aex))      (fun r -> try tcs.SetResult r with e -> tcs.SetException e)
+                | Canceled    -> continueTask tcs (compensation (TaskCanceledException ())) (fun r -> try tcs.SetResult r with e -> tcs.SetException e)
+            task.ConfigureAwait(false).GetAwaiter().UnsafeOnCompleted (fun () -> f task)
+            ValueTask<'T> tcs.Task
 
     /// Used to de-sugar try .. finally .. blocks in Computation Expressions.
     let inline tryFinally ([<InlineIfLambda>]compensation : unit -> unit) ([<InlineIfLambda>]body: unit -> ValueTask<'T>) : ValueTask<'T> =