Rewrite immutable.Set/Map.+ corner case

Author: MasseGuillaume

scalafix/input/src/main/scala/fix/SetMapSrc.scala

@@ -6,4 +6,6 @@ package fix
 class SetMapSrc(set: Set[Int], map: Map[Int, Int]) {
   set + (2, 3)
   map + (2 -> 3, 3 -> 4)
+  (set + (2, 3)).map(x => x)
+  set + (2, 3) - 4
 }

scalafix/output/src/main/scala/fix/SetMapSrc.scala

@@ -6,4 +6,6 @@ package fix
 class SetMapSrc(set: Set[Int], map: Map[Int, Int]) {
   set + 2 + 3
   map + (2 -> 3) + (3 -> 4)
+  (set + 2 + 3).map(x => x)
+  set + 2 + 3 - 4
 }

scalafix/rules/src/main/scala/fix/Scalacollectioncompat_newcollections.scala

@@ -165,15 +165,23 @@ case class Scalacollectioncompat_newcollections(index: SemanticdbIndex)
 
   def replaceSetMapPlus2(ctx: RuleCtx): Patch = {
     def rewritePlus(ap: Term.ApplyInfix, lhs: Term, op: Term.Name, rhs1: Term, rhs2: Term): Patch = {
-      ctx.replaceTree(
-        ap,
+
+      val tokensToReplace =
+        if(ap.tokens.headOption.map(_.is[Token.LeftParen]).getOrElse(false)) {
+          // don't drop surrounding parens
+          ap.tokens.slice(1, ap.tokens.size - 1)
+        } else ap.tokens
+
+      val newTree = 
         Term.ApplyInfix(
           Term.ApplyInfix(lhs, op, Nil, List(rhs1)),
           op,
           Nil,
           List(rhs2)
-        ).toString
-      )
+        ).syntax
+
+      ctx.removeTokens(tokensToReplace) +
+      tokensToReplace.headOption.map(x => ctx.addRight(x, newTree))
     }
 
     ctx.tree.collect {