From efc1bbc903563f8d774f9b1eb2cc3fda1c2b281c Mon Sep 17 00:00:00 2001
From: Albert Meltzer <7529386+kitbellew@users.noreply.github.com>
Date: Mon, 25 Mar 2024 09:03:56 -0700
Subject: [PATCH] RedundantBraces: remove parens and trailing comma

---
 .../scalafmt/rewrite/RedundantBraces.scala    | 45 ++++++++++--
 .../resources/rewrite/RedundantBraces.stat    | 33 +++++----
 .../test/resources/scala3/FewerBraces.stat    | 62 ++++++++--------
 .../resources/scala3/FewerBraces_fold.stat    | 36 +++++-----
 .../resources/scala3/FewerBraces_keep.stat    | 70 ++++++++++---------
 .../resources/scala3/FewerBraces_unfold.stat  | 54 +++++++-------
 6 files changed, 166 insertions(+), 134 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 5c01da426d..437b58ae0e 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
@@ -144,29 +144,60 @@ class RedundantBraces(implicit val ftoks: FormatTokens)
 
   private def onRightParen(left: Replacement)(implicit
       ft: FormatToken,
+      session: Session,
       style: ScalafmtConfig
   ): (Replacement, Replacement) = left.how match {
-    case ReplacementType.Remove => (left, removeToken)
+    case ReplacementType.Remove =>
+      val resOpt = getRightBraceBeforeRightParen(false).map { rb =>
+        // we'll use right brace later, when applying fewer-braces rewrite
+        (left, removeToken)
+      }
+      resOpt.orNull
+
     case ReplacementType.Replace if {
           val lft = left.ft
           val ro = ft.meta.rightOwner
           (lft.meta.rightOwner eq ro) &&
-          lft.right.is[Token.LeftBrace] &&
-          okToReplaceFunctionInSingleArgApply(ro).isDefined
+          lft.right.is[Token.LeftBrace]
         } =>
-      val pft = ftoks.prevNonComment(ft)
-      val rb = pft.left
-      if (rb.is[Token.RightBrace]) {
+      val pftOpt = getRightBraceBeforeRightParen(true)
+      def replaceIfAfterRightBrace = pftOpt.map { pft =>
+        val rb = pft.left
         // move right to the end of the function
         val rType = new ReplacementType.RemoveAndResurrect(ftoks.prev(pft))
         left -> replaceToken("}", rtype = rType) {
           // create a shifted token so that any child tree wouldn't own it
           new Token.RightBrace(rb.input, rb.dialect, rb.start + 1)
         }
-      } else null // don't know how to Replace
+      }
+      replaceIfAfterRightBrace.orNull // don't know how to Replace
     case _ => null
   }
 
+  private def getRightBraceBeforeRightParen(shouldBeRemoved: Boolean)(implicit
+      ft: FormatToken,
+      session: Session,
+      style: ScalafmtConfig
+  ): Option[FormatToken] = {
+    val pft = ftoks.prevNonComment(ft)
+    val ok = pft.left match {
+      case _: Token.Comma => // looks like trailing comma
+        val pft2 = ftoks.prevNonCommentBefore(pft)
+        pft2.left.is[Token.RightBrace] &&
+        session.isRemovedOnLeft(pft2, true) == shouldBeRemoved &&
+        session.isRemovedOnLeftOpt(pft).getOrElse {
+          val crt = ftoks.prev(pft)
+          val crepl = Replacement(this, crt, ReplacementType.Remove, style)
+          session.claim(crepl)(crt)
+          true
+        }
+      case _: Token.RightBrace =>
+        !session.isRemovedOnLeft(pft, !shouldBeRemoved)
+      case _ => false
+    }
+    if (ok) Some(pft) else None
+  }
+
   private def onLeftBrace(implicit
       ft: FormatToken,
       session: Session,
diff --git a/scalafmt-tests/src/test/resources/rewrite/RedundantBraces.stat b/scalafmt-tests/src/test/resources/rewrite/RedundantBraces.stat
index 1f181c001e..c74e7f06e1 100644
--- a/scalafmt-tests/src/test/resources/rewrite/RedundantBraces.stat
+++ b/scalafmt-tests/src/test/resources/rewrite/RedundantBraces.stat
@@ -1477,15 +1477,14 @@ object a {
   )
 }
 >>>
-Idempotency violated
-=> Diff (- obtained, + expected)
- object a {
--  mtd1(x => x + 1) + mtd2(x => x + 1 x +2)
-+  mtd1(x => x + 1) + mtd2(x =>
-+    x + 1
-+    x + 2,
-+  )
- }
+object a {
+  mtd1 { x =>
+    x + 1
+  } + mtd2 { x =>
+    x + 1
+    x + 2
+  }
+}
 <<< rewrite with trailing commas: func in parens, infix after, !allowFolding
 rewrite.trailingCommas.style = keep
 rewrite.trailingCommas.allowFolding = false
@@ -1503,14 +1502,14 @@ object a {
   )
 }
 >>>
-Idempotency violated
-=> Diff (- obtained, + expected)
-   ) + mtd2(
--    x => x + 1 x +2,
-+    x =>
-+      x + 1
-+      x + 2,
-   )
+object a {
+  mtd1 { x =>
+    x + 1
+  } + mtd2 { x =>
+    x + 1
+    x + 2
+  }
+}
 <<< rewrite with trailing commas: func in parens and braces, allowFolding
 rewrite.rules = [RedundantBraces, RedundantParens]
 rewrite.trailingCommas.style = keep
diff --git a/scalafmt-tests/src/test/resources/scala3/FewerBraces.stat b/scalafmt-tests/src/test/resources/scala3/FewerBraces.stat
index 83ad131015..79b61a784d 100644
--- a/scalafmt-tests/src/test/resources/scala3/FewerBraces.stat
+++ b/scalafmt-tests/src/test/resources/scala3/FewerBraces.stat
@@ -1934,18 +1934,18 @@ foo
   )
 >>>
 foo
-  .mtd1(x => x + 1)
-  .mtd2(x =>
+  .mtd1 { x =>
+    x + 1
+  }
+  .mtd2 { x =>
      x + 1
      x + 2
-  ,
-  )
-  .mtd3(x =>
+  }
+  .mtd3 { x =>
      x + 1
      x + 2
      x + 3
-  ,
-  )
+  }
 <<< rewrite to fewer braces: func in parens, trailing comma, !allowFolding
 rewrite.rules = [RedundantBraces]
 rewrite.trailingCommas.style = keep
@@ -1975,22 +1975,18 @@ foo
   )
 >>>
 foo
-  .mtd1(
-    x => x + 1,
-  )
-  .mtd2(
-    x =>
-       x + 1
-       x + 2
-    ,
-  )
-  .mtd3(
-    x =>
-       x + 1
-       x + 2
-       x + 3
-    ,
-  )
+  .mtd1 { x =>
+    x + 1
+  }
+  .mtd2 { x =>
+     x + 1
+     x + 2
+  }
+  .mtd3 { x =>
+     x + 1
+     x + 2
+     x + 3
+  }
 <<< rewrite to fewer braces: func in parens, infix after
 rewrite.rules = [RedundantBraces]
 rewrite.scala3.removeOptionalBraces = {
@@ -2017,14 +2013,18 @@ object a {
 }
 >>>
 object a:
-   mtd1(x => x + 1) + mtd2(x =>
-      x + 1
-      x + 2
-   ) + mtd3(x =>
-      x + 1
-      x + 2
-      x + 3
-   )
+   mtd1 { x =>
+     x + 1
+   }
+     + mtd2 { x =>
+        x + 1
+        x + 2
+     }
+     + mtd3 { x =>
+        x + 1
+        x + 2
+        x + 3
+     }
 <<< rewrite to fewer braces: func in parens and braces
 rewrite.rules = [RedundantBraces, RedundantParens]
 rewrite.scala3.removeOptionalBraces = {
diff --git a/scalafmt-tests/src/test/resources/scala3/FewerBraces_fold.stat b/scalafmt-tests/src/test/resources/scala3/FewerBraces_fold.stat
index 6fd7ecf593..43ee068b56 100644
--- a/scalafmt-tests/src/test/resources/scala3/FewerBraces_fold.stat
+++ b/scalafmt-tests/src/test/resources/scala3/FewerBraces_fold.stat
@@ -1693,14 +1693,14 @@ foo
     },
   )
 >>>
-foo.mtd1(x => x + 1).mtd2(x =>
+foo.mtd1(x => x + 1).mtd2 { x =>
    x + 1
-   x + 2,
-).mtd3(x =>
+   x + 2
+}.mtd3 { x =>
    x + 1
    x + 2
-   x + 3,
-)
+   x + 3
+}
 <<< rewrite to fewer braces: func in parens, trailing comma, !allowFolding
 rewrite.rules = [RedundantBraces]
 rewrite.trailingCommas.style = always
@@ -1729,18 +1729,14 @@ foo
     },
   )
 >>>
-foo.mtd1(
-  x => x + 1,
-).mtd2(
-  x =>
-     x + 1
-     x + 2,
-).mtd3(
-  x =>
-     x + 1
-     x + 2
-     x + 3,
-)
+foo.mtd1 { x => x + 1 }.mtd2 { x =>
+   x + 1
+   x + 2
+}.mtd3 { x =>
+   x + 1
+   x + 2
+   x + 3
+}
 <<< rewrite to fewer braces: func in parens, infix after
 rewrite.rules = [RedundantBraces]
 rewrite.scala3.removeOptionalBraces = {
@@ -1767,14 +1763,14 @@ object a {
 }
 >>>
 object a:
-   mtd1(x => x + 1) + mtd2(x =>
+   mtd1(x => x + 1) + mtd2 { x =>
       x + 1
       x + 2
-   ) + mtd3(x =>
+   } + mtd3 { x =>
       x + 1
       x + 2
       x + 3
-   )
+   }
 <<< rewrite to fewer braces: func in parens and braces
 rewrite.rules = [RedundantBraces, RedundantParens]
 rewrite.scala3.removeOptionalBraces = {
diff --git a/scalafmt-tests/src/test/resources/scala3/FewerBraces_keep.stat b/scalafmt-tests/src/test/resources/scala3/FewerBraces_keep.stat
index a80b517e08..66f163498b 100644
--- a/scalafmt-tests/src/test/resources/scala3/FewerBraces_keep.stat
+++ b/scalafmt-tests/src/test/resources/scala3/FewerBraces_keep.stat
@@ -1905,20 +1905,21 @@ foo
   )
 >>>
 foo
-  .mtd1(x =>
-    x + 1,
-  )
-  .mtd2(x =>
-     x + 1
-     x + 2
-  ,
-  )
-  .mtd3(x =>
-     x + 1
-     x + 2
-     x + 3
-  ,
-  )
+  .mtd1 {
+    x =>
+      x + 1
+  }
+  .mtd2 {
+    x =>
+       x + 1
+       x + 2
+  }
+  .mtd3 {
+    x =>
+       x + 1
+       x + 2
+       x + 3
+  }
 <<< rewrite to fewer braces: func in parens, trailing comma, !allowFolding
 rewrite.rules = [RedundantBraces]
 rewrite.trailingCommas.style = keep
@@ -1948,23 +1949,21 @@ foo
   )
 >>>
 foo
-  .mtd1(
+  .mtd1 {
     x =>
-      x + 1,
-  )
-  .mtd2(
+      x + 1
+  }
+  .mtd2 {
     x =>
        x + 1
        x + 2
-    ,
-  )
-  .mtd3(
+  }
+  .mtd3 {
     x =>
        x + 1
        x + 2
        x + 3
-    ,
-  )
+  }
 <<< rewrite to fewer braces: func in parens, infix after
 rewrite.rules = [RedundantBraces]
 rewrite.scala3.removeOptionalBraces = {
@@ -1991,16 +1990,21 @@ object a {
 }
 >>>
 object a:
-   mtd1(x =>
-     x + 1
-   ) + mtd2(x =>
-      x + 1
-      x + 2
-   ) + mtd3(x =>
-      x + 1
-      x + 2
-      x + 3
-   )
+   mtd1 {
+     x =>
+       x + 1
+   }
+     + mtd2 {
+       x =>
+          x + 1
+          x + 2
+     }
+     + mtd3 {
+       x =>
+          x + 1
+          x + 2
+          x + 3
+     }
 <<< rewrite to fewer braces: func in parens and braces
 rewrite.rules = [RedundantBraces, RedundantParens]
 rewrite.scala3.removeOptionalBraces = {
diff --git a/scalafmt-tests/src/test/resources/scala3/FewerBraces_unfold.stat b/scalafmt-tests/src/test/resources/scala3/FewerBraces_unfold.stat
index ec5c88fa69..e67e3736f5 100644
--- a/scalafmt-tests/src/test/resources/scala3/FewerBraces_unfold.stat
+++ b/scalafmt-tests/src/test/resources/scala3/FewerBraces_unfold.stat
@@ -1925,16 +1925,18 @@ foo
   )
 >>>
 foo
-  .mtd1(x => x + 1)
-  .mtd2(x =>
+  .mtd1 { x =>
+    x + 1
+  }
+  .mtd2 { x =>
      x + 1
-     x + 2,
-  )
-  .mtd3(x =>
+     x + 2
+  }
+  .mtd3 { x =>
      x + 1
      x + 2
-     x + 3,
-  )
+     x + 3
+  }
 <<< rewrite to fewer braces: func in parens, trailing comma, !allowFolding
 rewrite.rules = [RedundantBraces]
 rewrite.trailingCommas.style = always
@@ -1964,20 +1966,18 @@ foo
   )
 >>>
 foo
-  .mtd1(
-    x => x + 1,
-  )
-  .mtd2(
-    x =>
-       x + 1
-       x + 2,
-  )
-  .mtd3(
-    x =>
-       x + 1
-       x + 2
-       x + 3,
-  )
+  .mtd1 { x =>
+    x + 1
+  }
+  .mtd2 { x =>
+     x + 1
+     x + 2
+  }
+  .mtd3 { x =>
+     x + 1
+     x + 2
+     x + 3
+  }
 <<< rewrite to fewer braces: func in parens, infix after
 rewrite.rules = [RedundantBraces]
 rewrite.scala3.removeOptionalBraces = {
@@ -2004,16 +2004,18 @@ object a {
 }
 >>>
 object a:
-   mtd1(x => x + 1) +
-     mtd2(x =>
+   mtd1 { x =>
+     x + 1
+   } +
+     mtd2 { x =>
         x + 1
         x + 2
-     ) +
-     mtd3(x =>
+     } +
+     mtd3 { x =>
         x + 1
         x + 2
         x + 3
-     )
+     }
 <<< rewrite to fewer braces: func in parens and braces
 rewrite.rules = [RedundantBraces, RedundantParens]
 rewrite.scala3.removeOptionalBraces = {