Don't add a newline if there are no additional arguments before lambd…

…a. (#1923) Fixes #1922.
fsprojects · Jan 8, 2022 · 857d455 · 857d455
1 parent 87bb8a5
commit 857d455
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Showing 2 changed files with 24 additions and 1 deletion.
diff --git a/src/Fantomas.Tests/LambdaTests.fs b/src/Fantomas.Tests/LambdaTests.fs
@@ -1069,3 +1069,26 @@ leadingExpressionIsMultiline
      | Ok _ -> true
      | Error _ -> false)
 """
+
+[<Test>]
+let ``multiline lambda argument, 1922`` () =
+    formatSourceString
+        false
+        """
+let g =
+    Array.groupBy
+        (fun { partNumber = p
+               revisionNumber = r
+               processName = pn } -> p, r, pn)
+"""
+        config
+    |> prepend newline
+    |> should
+        equal
+        """
+let g =
+    Array.groupBy
+        (fun { partNumber = p
+               revisionNumber = r
+               processName = pn } -> p, r, pn)
+"""
diff --git a/src/Fantomas/CodePrinter.fs b/src/Fantomas/CodePrinter.fs
@@ -2211,7 +2211,7 @@ and genExpr astContext synExpr ctx =
                             +> indent
                             +> sepNln
                             +> col sepNln es (genExpr astContext)
-                            +> sepNln
+                            +> onlyIfNot (List.isEmpty es) sepNln
                             +> (sepOpenTFor lpr
                                 +> (!- "fun "
                                     +> col sepSpace pats (genPat astContext)