Fixed unnecessary parentheses in last tuple item (fsprojects#3082)

CHANGELOG.md

@@ -1,5 +1,10 @@
 # Changelog
 
+## 6.3.15 - 2024-09-14
+
+### Fixed
+* Non needed parentheses are added around lambda call from tuple/members [#3082](https://github.com/fsprojects/fantomas/issues/3082)
+
 ## 6.3.14 - 2024-09-14
 
 ### Fixed

src/Fantomas.Core.Tests/OperatorTests.fs

@@ -1354,7 +1354,7 @@ fun i -> sprintf "%i" i, fun () -> i
     |> should
         equal
         """
-(fun i -> sprintf "%i" i, (fun () -> i)) |> List.init foo |> Map.ofList
+(fun i -> sprintf "%i" i, fun () -> i) |> List.init foo |> Map.ofList
 """
 
 [<Test>]

src/Fantomas.Core.Tests/TupleTests.fs

@@ -551,3 +551,17 @@ let (clReducedValues, // some comment 1
      clSecondActualKeys): ClArray<'a> * ClArray<int> * ClArray<int> =
     reduce processor DeviceOnly resultLength clOffsets clFirstKeys clSecondKeys clValues
 """
+
+[<Test>]
+let ``unneeded parentheses on last tuple item, 3082`` () =
+    formatSourceString
+        """
+func ("/health", fun a b -> "")
+"""
+        config
+    |> prepend newline
+    |> should
+        equal
+        """
+func ("/health", fun a b -> "")
+"""

src/Fantomas.Core/CodePrinter.fs

@@ -1888,10 +1888,13 @@ let genTupleExpr (node: ExprTupleNode) =
         | _ -> expr
 
     let shortExpression =
-        col sepNone node.Items (function
+        let lastIndex = Array.length node.Children - 1
+
+        coli sepNone node.Items (fun i c ->
+            match c with
             | Choice1Of2 e ->
                 match e with
-                | IsLambdaOrIfThenElse e -> sepOpenT +> genExpr e +> sepCloseT
+                | IsLambdaOrIfThenElse e when i <> lastIndex -> sepOpenT +> genExpr e +> sepCloseT
                 | e -> genExpr (wrapInfixAppRhsInParenIfNeeded e)
             | Choice2Of2 comma -> genSingleTextNode comma +> addSpaceIfSpaceAfterComma)