diff --git a/scalafix/input/src/main/scala/fix/RetainSrc.scala b/scalafix/input/src/main/scala/fix/RetainSrc.scala
index 2ba1ca6c..056dc831 100644
--- a/scalafix/input/src/main/scala/fix/RetainSrc.scala
+++ b/scalafix/input/src/main/scala/fix/RetainSrc.scala
@@ -3,9 +3,10 @@ rule = "scala:fix.Scalacollectioncompat_NewCollections"
  */
 package fix
 
-import scala.collection.mutable.Map
+import scala.collection.mutable.{Map, Set}
 
-class MethodRenames(xs: Map[Int, Int]) {
+class MethodRenames(xs: Map[Int, Int], ys: Set[Int]) {
   xs.retain((_, _) => true)
   xs.retain{case (x, y) => true}
+  ys.retain(_ => true)
 }
\ No newline at end of file
diff --git a/scalafix/output/src/main/scala/fix/RetainSrc.scala b/scalafix/output/src/main/scala/fix/RetainSrc.scala
index 950570c6..c5ed3707 100644
--- a/scalafix/output/src/main/scala/fix/RetainSrc.scala
+++ b/scalafix/output/src/main/scala/fix/RetainSrc.scala
@@ -1,8 +1,9 @@
 package fix
 
-import scala.collection.mutable.Map
+import scala.collection.mutable.{Map, Set}
 
-class MethodRenames(xs: Map[Int, Int]) {
+class MethodRenames(xs: Map[Int, Int], ys: Set[Int]) {
   xs.filterInPlace{case (_, _) => true}
   xs.filterInPlace{case (x, y) => true}
+  ys.filterInPlace(_ => true)
 }
\ No newline at end of file
diff --git a/scalafix/rules/src/main/scala/fix/Scalacollectioncompat_NewCollections.scala b/scalafix/rules/src/main/scala/fix/Scalacollectioncompat_NewCollections.scala
index 8f660cb8..9d56ef1a 100644
--- a/scalafix/rules/src/main/scala/fix/Scalacollectioncompat_NewCollections.scala
+++ b/scalafix/rules/src/main/scala/fix/Scalacollectioncompat_NewCollections.scala
@@ -30,17 +30,28 @@ case class Scalacollectioncompat_NewCollections(index: SemanticdbIndex)
     Symbol("_root_.scala.runtime.Tuple3Zipped.Ops.zipped.")
   )
 
-  val retain = 
+  val retainMap = 
     SymbolMatcher.normalized(
       Symbol("_root_.scala.collection.mutable.MapLike.retain.")
     )
 
+  val retainSet = 
+    SymbolMatcher.normalized(
+      Symbol("_root_.scala.collection.mutable.SetLike.retain.")
+    )
+
+  def replaceMutableSet(ctx: RuleCtx) =
+    ctx.tree.collect {
+      case retainSet(n: Name) =>
+        ctx.replaceTree(n, "filterInPlace")
+    }.asPatch
+
   def replaceMutableMap(ctx: RuleCtx) =
     ctx.tree.collect {
-      case Term.Apply(Term.Select(_, retain(n: Name)), List(_: Term.PartialFunction)) =>
+      case Term.Apply(Term.Select(_, retainMap(n: Name)), List(_: Term.PartialFunction)) =>
         ctx.replaceTree(n, "filterInPlace")
 
-      case Term.Apply(Term.Select(_, retain(n: Name)), List(_: Term.Function)) =>
+      case Term.Apply(Term.Select(_, retainMap(n: Name)), List(_: Term.Function)) =>
         (for {
           name <- n.tokens.lastOption
           open <- ctx.tokenList.find(name)(t => t.is[Token.LeftParen])
@@ -128,11 +139,14 @@ case class Scalacollectioncompat_NewCollections(index: SemanticdbIndex)
     }.asPatch
 
   override def fix(ctx: RuleCtx): Patch = {
+    // println(ctx.index.database)
+
     replaceToList(ctx) +
       replaceSymbols(ctx) +
       replaceTupleZipped(ctx) +
       replaceCopyToBuffer(ctx) +
       replaceStreamAppend(ctx) +
-      replaceMutableMap(ctx)
+      replaceMutableMap(ctx) + 
+      replaceMutableSet(ctx)
   }
 }