Fix: print trivia for infix app. (#522)

* Fix: print trivia for infix app.

* Added test for both code branches

src/Fantomas.Tests/CompilerDirectivesTests.fs

@@ -966,4 +966,44 @@ try
     ()
 #endif
 with _ -> ()
+"""
+
+[<Test>]
+let ``preserve compile directive between piped functions (DEBUG), 512`` () =
+    formatSourceStringWithDefines ["DEBUG"] """let foo = [ 1 ]
+            |> List.sort
+#if DEBUG
+            |> List.rev
+#endif
+            |> List.sort
+"""  config
+    |> prepend newline
+    |> should equal """
+let foo =
+    [ 1 ]
+    |> List.sort
+#if DEBUG
+    |> List.rev
+#endif
+    |> List.sort
+"""
+
+[<Test>]
+let ``preserve compile directive between piped functions, 512`` () =
+    formatSourceString false """let foo = [ 1 ]
+            |> List.sort
+#if DEBUG
+            |> List.rev
+#endif
+            |> List.sort
+"""  config
+    |> prepend newline
+    |> should equal """
+let foo =
+    [ 1 ]
+    |> List.sort
+#if DEBUG
+    |> List.rev
+#endif
+    |> List.sort
 """

src/Fantomas/CodePrinter.fs

@@ -1229,7 +1229,7 @@ and genInfixApps astContext hasNewLine synExprs =
                 genExpr ctx))
         +> genInfixApps astContext (hasNewLine || checkNewLine e es) es
     | (s, opE, e)::es when(hasNewLine) ->
-        (sepNln +> tok opE.Range s +> sepSpace +> genExpr astContext e)
+        (sepNln +> (tok opE.Range s |> genTrivia opE.Range) +> sepSpace +> genExpr astContext e)
         +> genInfixApps astContext (hasNewLine || checkNewLine e es) es
     | (s, opE, e)::es when(NoSpaceInfixOps.Contains s) ->
         let wrapExpr f =