Keep newline above match bang.

src/Fantomas.Tests/ComputationExpressionTests.fs

@@ -2276,3 +2276,56 @@ let setup =
              value)
     }
 """
+
+[<Test>]
+let ``keep new line before match bang, 1313`` () =
+    formatSourceString
+        false
+        """
+  /// a codefix that generates union cases for an incomplete match expression
+  let generateUnionCases =
+    ifDiagnosticByMessage
+      (fun diagnostic codeActionParams ->
+        asyncResult {
+          let! (tyRes, line, lines) = getParseResultsForFile fileName pos
+
+          match! generateCases tyRes pos lines line |> Async.map Ok with
+          | CoreResponse.Res (insertString: string, insertPosition) ->
+              return
+                [ { SourceDiagnostic = Some diagnostic
+                    File = codeActionParams.TextDocument
+                    Title = "Generate union pattern match cases"
+                    Edits = [| { Range = range; NewText = replaced } |]
+                    Kind = Fix } ]
+
+          | _ -> return []
+        }
+        |> AsyncResult.foldResult id (fun _ -> []))
+      "Incomplete pattern matches on this expression. For example"
+"""
+        config
+    |> prepend newline
+    |> should
+        equal
+        """
+/// a codefix that generates union cases for an incomplete match expression
+let generateUnionCases =
+    ifDiagnosticByMessage
+        (fun diagnostic codeActionParams ->
+            asyncResult {
+                let! (tyRes, line, lines) = getParseResultsForFile fileName pos
+
+                match! generateCases tyRes pos lines line |> Async.map Ok with
+                | CoreResponse.Res (insertString: string, insertPosition) ->
+                    return
+                        [ { SourceDiagnostic = Some diagnostic
+                            File = codeActionParams.TextDocument
+                            Title = "Generate union pattern match cases"
+                            Edits = [| { Range = range; NewText = replaced } |]
+                            Kind = Fix } ]
+
+                | _ -> return []
+            }
+            |> AsyncResult.foldResult id (fun _ -> []))
+        "Incomplete pattern matches on this expression. For example"
+"""

src/Fantomas/CodePrinter.fs

@@ -2716,6 +2716,7 @@ and genExpr astContext synExpr ctx =
             | SynExpr.Lambda _ -> genTriviaFor SynExpr_Lambda synExpr.Range
             | SynExpr.ForEach _ -> genTriviaFor SynExpr_ForEach synExpr.Range
             | SynExpr.Match _ -> genTriviaFor SynExpr_Match synExpr.Range
+            | SynExpr.MatchBang _ -> genTriviaFor SynExpr_MatchBang synExpr.Range
             | SynExpr.YieldOrReturn _ -> genTriviaFor SynExpr_YieldOrReturn synExpr.Range
             | SynExpr.YieldOrReturnFrom _ -> genTriviaFor SynExpr_YieldOrReturnFrom synExpr.Range
             | SynExpr.TryFinally _ -> genTriviaFor SynExpr_TryFinally synExpr.Range