From f50f8e890dfaf07ddbaf365b53da3851a7b83c48 Mon Sep 17 00:00:00 2001
From: Vlad Zarytovskii <vzaritovsky@hotmail.com>
Date: Tue, 23 Jan 2024 12:59:14 +0100
Subject: [PATCH] Preserve original stacktrace in state machines if available
 (#16568)

* Preserve original stacktrace in state machines if available

* Update release notes

* Automated command ran: fantomas

  Co-authored-by: vzarytovskii <1260985+vzarytovskii@users.noreply.github.com>

---------

Co-authored-by: github-actions[bot] <41898282+github-actions[bot]@users.noreply.github.com>
---
 docs/release-notes/.FSharp.Core/8.0.300.md | 3 +++
 src/FSharp.Core/resumable.fs               | 8 ++++++--
 2 files changed, 9 insertions(+), 2 deletions(-)
 create mode 100644 docs/release-notes/.FSharp.Core/8.0.300.md

diff --git a/docs/release-notes/.FSharp.Core/8.0.300.md b/docs/release-notes/.FSharp.Core/8.0.300.md
new file mode 100644
index 00000000000..9acf7d07635
--- /dev/null
+++ b/docs/release-notes/.FSharp.Core/8.0.300.md
@@ -0,0 +1,3 @@
+### Fixed
+
+* Preserve original stack traces in resumable state machines generated code if available. ([PR #16568](https://github.com/dotnet/fsharp/pull/16568))
\ No newline at end of file
diff --git a/src/FSharp.Core/resumable.fs b/src/FSharp.Core/resumable.fs
index e63e79f92dd..24131ea155f 100644
--- a/src/FSharp.Core/resumable.fs
+++ b/src/FSharp.Core/resumable.fs
@@ -115,6 +115,7 @@ module StateMachineHelpers =
             "__stateMachine should always be guarded by __useResumableCode and only used in valid state machine implementations"
 
 module ResumableCode =
+    open System.Runtime.ExceptionServices
 
     let inline GetResumptionFunc (sm: byref<ResumableStateMachine<'Data>>) =
         sm.ResumptionDynamicInfo.ResumptionFunc
@@ -294,7 +295,10 @@ module ResumableCode =
             // reraise at the end of the finally block
             match savedExn with
             | None -> true
-            | Some exn -> raise exn
+            | Some exn ->
+                // This should preserve initial location for the failure (file + line, given they're available).
+                ExceptionDispatchInfo.Capture(exn).Throw()
+                true
         else
             let rf = GetResumptionFunc &sm
 
@@ -384,7 +388,7 @@ module ResumableCode =
                 if __stack_fin then
                     match savedExn with
                     | None -> ()
-                    | Some exn -> raise exn
+                    | Some exn -> ExceptionDispatchInfo.Capture(exn).Throw()
 
                 __stack_fin
             //-- RESUMABLE CODE END