From 26a37fa2afef563ae3572193cd06d89699198d9e Mon Sep 17 00:00:00 2001
From: dawe <dawedawe@posteo.de>
Date: Sun, 2 Jun 2024 23:45:49 +0200
Subject: [PATCH] - add missing construction of return info node for
 deconstructed tuples to fix 2942 - add test cases - add CHANGELOG entry

---
 CHANGELOG.md                          |  5 ++++
 src/Fantomas.Core.Tests/TupleTests.fs | 36 +++++++++++++++++++++++++++
 src/Fantomas.Core/CodePrinter.fs      |  6 +++++
 3 files changed, 47 insertions(+)

diff --git a/CHANGELOG.md b/CHANGELOG.md
index 4895deda64..f8a5d3fa57 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -1,5 +1,10 @@
 # Changelog
 
+## [Unreleased]
+
+### Fixed
+* Fix loss of tuple type annotation without parens. [#2942](https://github.com/fsprojects/fantomas/issues/2942)
+
 ## 6.3.7 - 2024-06-01
 
 ### Fixed
diff --git a/src/Fantomas.Core.Tests/TupleTests.fs b/src/Fantomas.Core.Tests/TupleTests.fs
index 55aa349a34..a5c7d11ce3 100644
--- a/src/Fantomas.Core.Tests/TupleTests.fs
+++ b/src/Fantomas.Core.Tests/TupleTests.fs
@@ -515,3 +515,39 @@ a |> fun b -> if b then 0 else 1
         """
 a |> (fun b -> if b then 0 else 1), 2
 """
+
+[<Test>]
+let ``removes type annotation without parens, 2942`` () =
+    formatSourceString
+        """
+let clReducedValues, clFirstActualKeys, clSecondActualKeys: ClArray<'a> * ClArray<int> * ClArray<int> =
+    reduce processor DeviceOnly resultLength clOffsets clFirstKeys clSecondKeys clValues
+"""
+        config
+    |> prepend newline
+    |> should
+        equal
+        """
+let clReducedValues, clFirstActualKeys, clSecondActualKeys: ClArray<'a> * ClArray<int> * ClArray<int> =
+    reduce processor DeviceOnly resultLength clOffsets clFirstKeys clSecondKeys clValues
+"""
+
+[<Test>]
+let ``removes type annotation without parens multiline, 2942`` () =
+    formatSourceString
+        """
+let clReducedValues, // some comment 1
+    clFirstActualKeys, // some comment 2
+    clSecondActualKeys: ClArray<'a> * ClArray<int> * ClArray<int> =
+        reduce processor DeviceOnly resultLength clOffsets clFirstKeys clSecondKeys clValues
+"""
+        config
+    |> prepend newline
+    |> should
+        equal
+        """
+let (clReducedValues, // some comment 1
+     clFirstActualKeys, // some comment 2
+     clSecondActualKeys): ClArray<'a> * ClArray<int> * ClArray<int> =
+    reduce processor DeviceOnly resultLength clOffsets clFirstKeys clSecondKeys clValues
+"""
diff --git a/src/Fantomas.Core/CodePrinter.fs b/src/Fantomas.Core/CodePrinter.fs
index 4694bec31f..de5cba95e8 100644
--- a/src/Fantomas.Core/CodePrinter.fs
+++ b/src/Fantomas.Core/CodePrinter.fs
@@ -2986,6 +2986,12 @@ let genBinding (b: BindingNode) (ctx: Context) : Context =
 
             let genDestructedTuples =
                 expressionFitsOnRestOfLine (genPat pat) (sepOpenT +> genPat pat +> sepCloseT)
+                +> optSingle
+                    (fun (rt: BindingReturnInfoNode) ->
+                        genSingleTextNode rt.Colon
+                        +> sepSpace
+                        +> atCurrentColumnIndent (genType rt.Type))
+                    b.ReturnType
 
             genXml b.XmlDoc
             +> genAttrAndPref