Guard against a newline induced precedence change

CHANGELOG.md

@@ -1,9 +1,9 @@
 # Changelog
 
-## [Unreleased]
+## 6.3.8 - 2024-06-06
 
 ### Fixed
-* Fix loss of tuple type annotation without parens. [#2942](https://github.com/fsprojects/fantomas/issues/2942)
+* Fix precedence change of `||>` due to inserted newline. [#2866](https://github.com/fsprojects/fantomas/issues/2866)
 
 ## 6.3.7 - 2024-06-01
 

src/Fantomas.Core.Tests/PatternMatchingTests.fs

@@ -2286,3 +2286,26 @@ match synExpr with
     ) -> Some ident.idRange
 | _ -> defaultTraverse synExpr
 """
+
+[<Test>]
+let ``insertion of a newline changes precedence of the ||> operator, 2866`` () =
+    formatSourceString
+        """
+let value =
+    match "string" with
+    | "value" -> "1", "2"
+    | _ -> "111111111111111111111111111111111111111111111111111111111111111111111", "22222222222222222222222222222222222"
+    ||> createTuple
+"""
+        config
+    |> prepend newline
+    |> should
+        equal
+        """
+let value =
+    (match "string" with
+     | "value" -> "1", "2"
+     | _ ->
+         "111111111111111111111111111111111111111111111111111111111111111111111", "22222222222222222222222222222222222")
+    ||> createTuple
+"""

src/Fantomas.Core/CodePrinter.fs

@@ -2163,7 +2163,7 @@ let genMultilineInfixExpr (node: ExprInfixAppNode) =
         match node.LeftHandSide with
         | IsIfThenElse _ when (ctx.Config.IndentSize - 1 <= node.Operator.Text.Length) ->
             autoParenthesisIfExpressionExceedsPageWidth (genExpr node.LeftHandSide) ctx
-        | Expr.Match _ when (ctx.Config.IndentSize <= node.Operator.Text.Length) ->
+        | Expr.Match _ when (ctx.Config.IndentSize - 1 <= node.Operator.Text.Length) ->
             let ctxAfterMatch = genExpr node.LeftHandSide ctx
 
             let lastClauseIsSingleLine =