From 26559432860acd7cc69ef282945cfd758f9f3af0 Mon Sep 17 00:00:00 2001
From: nojaf <florian.verdonck@outlook.com>
Date: Thu, 26 Feb 2026 14:10:30 +0100
Subject: [PATCH] Add regression test for issue 2844: trivia around paren
 lambda with conditional compilation

---
 CHANGELOG.md                                  |  1 +
 .../CompilerDirectivesTests.fs                | 43 +++++++++++++++++++
 2 files changed, 44 insertions(+)

diff --git a/CHANGELOG.md b/CHANGELOG.md
index 599a16e66..b09e66113 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -5,6 +5,7 @@
 ### Fixed
 
 - End of line comments after infix operators are preserved correctly. [#2287](https://github.com/fsprojects/fantomas/issues/2287)
+- Trivia around paren lambda with conditional compilation no longer causes merge error. [#2844](https://github.com/fsprojects/fantomas/issues/2844)
 
 ## [8.0.0-alpha-002] - 2025-12-15
 
diff --git a/src/Fantomas.Core.Tests/CompilerDirectivesTests.fs b/src/Fantomas.Core.Tests/CompilerDirectivesTests.fs
index 34aa3ebb2..b35c44466 100644
--- a/src/Fantomas.Core.Tests/CompilerDirectivesTests.fs
+++ b/src/Fantomas.Core.Tests/CompilerDirectivesTests.fs
@@ -3240,3 +3240,46 @@ let CombineImportedAssembliesTask
 
     ()
 """
+
+[<Test>]
+let ``trivia around paren lambda with conditional compilation, 2844`` () =
+    formatSourceString
+        """
+Program.statefulWithCmdMsg
+|> (fun program ->
+            { program with
+                CanReuseView = ViewHelper.canReuseView
+                SyncAction =
+                    (fun fn ->
+                        program.SyncAction
+                            (
+#if IOS
+                            // iOS animates by default layout changes, we don't want that
+                            fun () -> UIKit.UIView.PerformWithoutAnimation(fn)
+#else
+                            fn
+#endif
+                        )) })
+"""
+        config
+    |> prepend newline
+    |> should
+        equal
+        """
+Program.statefulWithCmdMsg
+|> (fun program ->
+    { program with
+        CanReuseView = ViewHelper.canReuseView
+        SyncAction =
+            (fun fn ->
+                program.SyncAction
+                    (
+#if IOS
+                    // iOS animates by default layout changes, we don't want that
+                    fun () -> UIKit.UIView.PerformWithoutAnimation(fn)
+#else
+                    fn
+#endif
+                ))
+    })
+"""