From 51a5a5c9386eb012a146af5d8bd6a5edb61ab06c Mon Sep 17 00:00:00 2001
From: Albert Meltzer <7529386+kitbellew@users.noreply.github.com>
Date: Wed, 24 Jun 2020 10:51:20 -0700
Subject: [PATCH] Router: keep blank line in empty case clause body

---
 .../src/main/scala/org/scalafmt/internal/Router.scala  | 10 ++++++----
 scalafmt-tests/src/test/resources/default/Case.stat    |  1 +
 2 files changed, 7 insertions(+), 4 deletions(-)

diff --git a/scalafmt-core/shared/src/main/scala/org/scalafmt/internal/Router.scala b/scalafmt-core/shared/src/main/scala/org/scalafmt/internal/Router.scala
index 4bb3fc0e37..07db525b44 100644
--- a/scalafmt-core/shared/src/main/scala/org/scalafmt/internal/Router.scala
+++ b/scalafmt-core/shared/src/main/scala/org/scalafmt/internal/Router.scala
@@ -405,15 +405,17 @@ class Router(formatOps: FormatOps) {
         singleLineSplit +: multiLineSplits
 
       // Case arrow
-      case tok @ FormatToken(arrow @ T.RightArrow(), right, between)
-          if leftOwner.isInstanceOf[Case] =>
+      case tok @ FormatToken(_: T.RightArrow, right, _) if leftOwner.is[Case] =>
         val caseStat = leftOwner.asInstanceOf[Case]
         if (right.is[T.LeftBrace] && (caseStat.body eq rightOwner))
           // Redundant {} block around case statements.
           Seq(Split(Space, 0).withIndent(-2, rightOwner.tokens.last, After))
         else {
-          def newlineSplit(cost: Int) =
-            Split(NewlineT(noIndent = rhsIsCommentedOut(tok)), cost)
+          def newlineSplit(cost: Int) = {
+            val noIndent = rhsIsCommentedOut(tok)
+            val isDouble = tok.hasBlankLine && caseStat.body.tokens.isEmpty
+            Split(NewlineT(isDouble = isDouble, noIndent = noIndent), cost)
+          }
           def foldedSplits =
             caseStat.body match {
               case _ if right.is[T.KwCase] || isSingleLineComment(right) =>
diff --git a/scalafmt-tests/src/test/resources/default/Case.stat b/scalafmt-tests/src/test/resources/default/Case.stat
index 437d71e985..48330b7005 100644
--- a/scalafmt-tests/src/test/resources/default/Case.stat
+++ b/scalafmt-tests/src/test/resources/default/Case.stat
@@ -212,6 +212,7 @@ object a {
 object a {
   val a = a match {
     case a =>
+
     case b =>
   }
 }