From 6a011845eebaad215aaa712fb5c7612b07586537 Mon Sep 17 00:00:00 2001
From: Albert Meltzer <7529386+kitbellew@users.noreply.github.com>
Date: Sat, 28 Sep 2024 00:05:11 -0700
Subject: [PATCH] RedundantBraces: keep around do-while within for

---
 .../scalafmt/rewrite/RedundantBraces.scala    |  9 ++++
 .../resources/rewrite/RedundantBraces.stat    | 46 ++++++++-----------
 2 files changed, 27 insertions(+), 28 deletions(-)

diff --git a/scalafmt-core/shared/src/main/scala/org/scalafmt/rewrite/RedundantBraces.scala b/scalafmt-core/shared/src/main/scala/org/scalafmt/rewrite/RedundantBraces.scala
index 9d6fede46d..3e76d3c978 100644
--- a/scalafmt-core/shared/src/main/scala/org/scalafmt/rewrite/RedundantBraces.scala
+++ b/scalafmt-core/shared/src/main/scala/org/scalafmt/rewrite/RedundantBraces.scala
@@ -555,6 +555,15 @@ class RedundantBraces(implicit val ftoks: FormatTokens)
       case p: Term.Match => p.expr eq b
       case p: Type.Match => p.tpe eq b
 
+      case p: Term.ForClause if p.body eq b =>
+        @tailrec
+        def iter(t: Tree): Boolean = t match {
+          case _: Term.Do => true
+          case Term.Block(x :: Nil) => iter(x)
+          case _ => false
+        }
+        iter(stat)
+
       case parent => SyntacticGroupOps.groupNeedsParenthesis(
           TreeSyntacticGroup(parent),
           TreeSyntacticGroup(stat),
diff --git a/scalafmt-tests/shared/src/test/resources/rewrite/RedundantBraces.stat b/scalafmt-tests/shared/src/test/resources/rewrite/RedundantBraces.stat
index b2c42e5ef2..d6fcfbbee1 100644
--- a/scalafmt-tests/shared/src/test/resources/rewrite/RedundantBraces.stat
+++ b/scalafmt-tests/shared/src/test/resources/rewrite/RedundantBraces.stat
@@ -2071,20 +2071,15 @@ for (taskSet <- sortedTaskSets; maxLocality <- taskSet.myLocalityLevels) {
   } while (launchedTask)
 }
 >>>
-test does not parse: [dialect scala213] `end of file` expected but `while` found
-  availableCpus,
-  tasks
-) while (launchedTask)
-  ^
-====== full result: ======
-for (taskSet <- sortedTaskSets; maxLocality <- taskSet.myLocalityLevels)
-do launchedTask = resourceOfferSingleTaskSet(
-  taskSet,
-  maxLocality,
-  shuffledOffers,
-  availableCpus,
-  tasks
-) while (launchedTask)
+for (taskSet <- sortedTaskSets; maxLocality <- taskSet.myLocalityLevels) {
+  do launchedTask = resourceOfferSingleTaskSet(
+    taskSet,
+    maxLocality,
+    shuffledOffers,
+    availableCpus,
+    tasks
+  ) while (launchedTask)
+}
 <<< #4133 do-while within for, extra block
 rewrite.redundantBraces.maxLines = 100
 ===
@@ -2095,17 +2090,12 @@ for (taskSet <- sortedTaskSets; maxLocality <- taskSet.myLocalityLevels) {{
   } while (launchedTask)
 }}
 >>>
-test does not parse: [dialect scala213] `end of file` expected but `while` found
-  availableCpus,
-  tasks
-) while (launchedTask)
-  ^
-====== full result: ======
-for (taskSet <- sortedTaskSets; maxLocality <- taskSet.myLocalityLevels)
-do launchedTask = resourceOfferSingleTaskSet(
-  taskSet,
-  maxLocality,
-  shuffledOffers,
-  availableCpus,
-  tasks
-) while (launchedTask)
+for (taskSet <- sortedTaskSets; maxLocality <- taskSet.myLocalityLevels) {
+  do launchedTask = resourceOfferSingleTaskSet(
+    taskSet,
+    maxLocality,
+    shuffledOffers,
+    availableCpus,
+    tasks
+  ) while (launchedTask)
+}