Remove LinearSeq rewrite & Add compat import when doing .to[X] rewrite

Author: MasseGuillaume

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

@@ -0,0 +1,8 @@
+/*
+rule = "scala:fix.CrossCompat"
+ */
+package fix
+
+object TraversableBug {
+  Array(1).to[List]
+}

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

@@ -0,0 +1,9 @@
+
+
+
+package fix
+
+import scala.collection.compat._
+object TraversableBug {
+  Array(1).to(List)
+}

scalafix/output212/src/main/scala/fix/LinearSeqSrc.scala

@@ -255,11 +255,6 @@ trait Stable212Base extends CrossCompatibility { self: SemanticRule =>
         "scala.collection.Traversable" -> "scala.collection.Iterable"
       )
 
-    val linearSeqToList =
-      ctx.replaceSymbols(
-        "scala.collection.LinearSeq" -> "scala.collection.immutable.List",
-      )
-
     import scala.meta.contrib._
     val hasTraversable =
         ctx.tree.exists {
@@ -272,7 +267,7 @@ trait Stable212Base extends CrossCompatibility { self: SemanticRule =>
       if (hasTraversable) addCompatImport(ctx)
       else Patch.empty
 
-    traversableToIterable + linearSeqToList + compatImport
+    traversableToIterable + compatImport
   }
 
   def replaceSymbolicFold(ctx: RuleCtx): Patch = {
@@ -362,15 +357,17 @@ trait Stable212Base extends CrossCompatibility { self: SemanticRule =>
             CanBuildFrom(paramss, body, ctx, collectionCanBuildFrom, nothing)
       }.asPatch
 
-    val imports =
-      ctx.tree.collect {
-        case i: Importee if collectionCanBuildFromImport.matches(i) =>
-            ctx.removeImportee(i)
-      }.asPatch
+    if (useSites.nonEmpty) {
+      val imports =
+        ctx.tree.collect {
+          case i: Importee if collectionCanBuildFromImport.matches(i) =>
+              ctx.removeImportee(i)
+        }.asPatch
 
-    val compatImport = addCompatImport(ctx)
+      val compatImport = addCompatImport(ctx)
 
-    if (useSites.nonEmpty) useSites + imports + compatImport
+      useSites + imports + compatImport
+    }
     else Patch.empty
   }
 
@@ -401,29 +398,44 @@ trait Stable212Base extends CrossCompatibility { self: SemanticRule =>
    }
 
   def replaceToList(ctx: RuleCtx): Patch = {
-    ctx.tree.collect {
-      case iterator(t: Name) =>
-        ctx.replaceTree(t, "iterator")
+    val replaceToIterator =
+      ctx.tree.collect {
+        case iterator(t: Name) =>
+          ctx.replaceTree(t, "iterator")
+      }.asPatch
 
-      case Term.ApplyType(Term.Select(_, t @ toTpe(n: Name)), _) if !handledTo.contains(n) =>
-        trailingBrackets(n, ctx).map { case (open, close) =>
-          ctx.replaceToken(open, "(") + ctx.replaceToken(close, ")")
-        }.asPatch
+    val replaceTo =
+      ctx.tree.collect {
+        case Term.ApplyType(Term.Select(_, t @ toTpe(n: Name)), _) if !handledTo.contains(n) =>
+          trailingBrackets(n, ctx).map { case (open, close) =>
+            ctx.replaceToken(open, "(") + ctx.replaceToken(close, ")")
+          }.asPatch
+
+        case Term.Select(_, to @ toTpe(_)) =>
+          val synth = ctx.index.synthetics.find(_.position.end == to.pos.end)
+          synth.map{ s =>
+            val Term.Apply(_, List(toCol)) = s.text.parse[Term].get
+            val col = extractCollection(toCol)
+            ctx.addRight(to, "(" + col + ")")
+          }.getOrElse(Patch.empty)
+      }.asPatch
 
-      case Term.Select(_, to @ toTpe(_)) =>
-        val synth = ctx.index.synthetics.find(_.position.end == to.pos.end)
-        synth.map{ s =>
-          val Term.Apply(_, List(toCol)) = s.text.parse[Term].get
-          val col = extractCollection(toCol)
-          ctx.addRight(to, "(" + col + ")")
-        }.getOrElse(Patch.empty)
-    }.asPatch
+    val compatImport =
+      if (replaceTo.nonEmpty) addCompatImport(ctx)
+      else Patch.empty
+
+    compatImport + replaceToIterator + replaceTo
   }
 
+  private val compatImportAdded = mutable.Set[Input]()
 
   def addCompatImport(ctx: RuleCtx): Patch = {
-    if (isCrossCompatible) ctx.addGlobalImport(importer"scala.collection.compat._")
-    else Patch.empty
+    if (isCrossCompatible && !compatImportAdded.contains(ctx.input)) {
+      compatImportAdded += ctx.input
+      ctx.addGlobalImport(importer"scala.collection.compat._")
+    } else {
+      Patch.empty
+    }
   }
 
   override def fix(ctx: RuleCtx): Patch = {