From 7fad633b686fea1dfcc372265f9871e31647a79b Mon Sep 17 00:00:00 2001
From: Albert Meltzer <7529386+kitbellew@users.noreply.github.com>
Date: Thu, 7 Mar 2024 22:11:36 -0800
Subject: [PATCH 1/2] Test redundant parens and braces, one-line func

---
 .../src/test/resources/rewrite/RedundantParens.stat      | 9 +++++++++
 1 file changed, 9 insertions(+)

diff --git a/scalafmt-tests/src/test/resources/rewrite/RedundantParens.stat b/scalafmt-tests/src/test/resources/rewrite/RedundantParens.stat
index 47b44540a2..51bbf6ae55 100644
--- a/scalafmt-tests/src/test/resources/rewrite/RedundantParens.stat
+++ b/scalafmt-tests/src/test/resources/rewrite/RedundantParens.stat
@@ -1404,3 +1404,12 @@ object A {
       Option(""),
     ).map(identity)
 }
+<<< func in parens and braces, single line
+rewrite.rules = [RedundantBraces, RedundantParens]
+===
+foo.mtd({ x => x + 1 })
+>>>
+Idempotency violated
+=> Diff (- obtained, + expected)
+-foo.mtd(x => x + 1)
++foo.mtd { x => x + 1 }

From 44e0c737513f5f4c231a718b6bf02f9b84956079 Mon Sep 17 00:00:00 2001
From: Albert Meltzer <7529386+kitbellew@users.noreply.github.com>
Date: Thu, 7 Mar 2024 16:59:27 -0800
Subject: [PATCH 2/2] FormatWriter: mind rewritten tokens for {} -> ()

---
 .../main/scala/org/scalafmt/internal/FormatWriter.scala  | 2 +-
 .../scala/org/scalafmt/rewrite/RedundantBraces.scala     | 9 +++++++--
 .../src/test/resources/rewrite/RedundantParens.stat      | 5 +----
 3 files changed, 9 insertions(+), 7 deletions(-)

diff --git a/scalafmt-core/shared/src/main/scala/org/scalafmt/internal/FormatWriter.scala b/scalafmt-core/shared/src/main/scala/org/scalafmt/internal/FormatWriter.scala
index f4cdd8b515..6fa02b7a2b 100644
--- a/scalafmt-core/shared/src/main/scala/org/scalafmt/internal/FormatWriter.scala
+++ b/scalafmt-core/shared/src/main/scala/org/scalafmt/internal/FormatWriter.scala
@@ -162,7 +162,7 @@ class FormatWriter(formatOps: FormatOps) {
           val ok = tok.meta.leftOwner match {
             case b: Term.Block =>
               checkApply(b) && RedundantBraces.canRewriteBlockWithParens(b) &&
-              b.parent.exists(_.tokens.last.start == rb.start)
+              b.parent.exists(tokens.getLast(_) eq tok)
             case f: Term.FunctionTerm =>
               checkApply(f) && RedundantBraces.canRewriteFuncWithParens(f)
             case t @ TreeOps.SingleArgInBraces(arg) =>
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 5d0b275ff0..1acf0716cb 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
@@ -27,14 +27,19 @@ object RedundantBraces extends Rewrite with FormatTokensRewrite.RuleFactory {
       case _ => false
     }
 
-  def canRewriteBlockWithParens(b: Term.Block): Boolean =
+  def canRewriteBlockWithParens(b: Term.Block)(implicit
+      ftoks: FormatTokens
+  ): Boolean =
     getBlockSingleStat(b).exists(canRewriteStatWithParens)
 
-  def canRewriteStatWithParens(t: Stat): Boolean =
+  def canRewriteStatWithParens(t: Stat)(implicit ftoks: FormatTokens): Boolean =
     t match {
       case f: Term.FunctionTerm => canRewriteFuncWithParens(f)
       case _: Term.Assign => false // disallowed in 2.13
       case _: Defn => false
+      case _: Term.PartialFunction => false
+      case b @ Term.Block(s :: Nil) if !ftoks.isEnclosedInMatching(b) =>
+        canRewriteStatWithParens(s)
       case _ => true
     }
 
diff --git a/scalafmt-tests/src/test/resources/rewrite/RedundantParens.stat b/scalafmt-tests/src/test/resources/rewrite/RedundantParens.stat
index 51bbf6ae55..74ee3f3542 100644
--- a/scalafmt-tests/src/test/resources/rewrite/RedundantParens.stat
+++ b/scalafmt-tests/src/test/resources/rewrite/RedundantParens.stat
@@ -1409,7 +1409,4 @@ rewrite.rules = [RedundantBraces, RedundantParens]
 ===
 foo.mtd({ x => x + 1 })
 >>>
-Idempotency violated
-=> Diff (- obtained, + expected)
--foo.mtd(x => x + 1)
-+foo.mtd { x => x + 1 }
+foo.mtd(x => x + 1)