Avoid boxing primitives with Any2StringAdd

output/src/main/scala/fix/scala213/Any2StringAdd.scala

@@ -29,23 +29,23 @@ abstract class Any2StringAdd {
   //
   def unit1 = unit.toString + s
   def bool1 = bool.toString + s
-  def byte1 = byte.toString + s
+  def byte1 = "" + byte + s
   def byte2 = byte + byte
-  def short1 = short.toString + s
+  def short1 = "" + short + s
   def short2 = short + short
-  def char1 = char.toString + s
+  def char1 = "" + char + s
   def char2 = char + char
-  def int1 = int.toString + s
+  def int1 = "" + int + s
   def int2 = int + int
-  def long1 = long.toString + s
+  def long1 = "" + long + s
   def long2 = long + long
-  def float1 = float.toString + s
+  def float1 = "" + float + s
   def float2 = float + float
-  def double1 = double.toString + s
+  def double1 = "" + double + s
   def double2 = double + double
 
   // With infix operators, make sure to use parens
   def parens1 = (Nil ++ Nil).toString + s
-  def parens2 = (int + int).toString + s
+  def parens2 = "" + (int + int) + s
   def parens3 = {Nil ++ Nil}.toString + s
 }

rewrites/src/main/scala/fix/scala213/Any2StringAdd.scala

@@ -5,8 +5,8 @@ import scalafix.v1._
 import scala.meta._
 
 object Any2StringAdd {
-  val plusString = SymbolMatcher.exact(
-    "scala/Predef.any2stringadd#`+`().",
+  val any2stringaddPlusString = SymbolMatcher.exact("scala/Predef.any2stringadd#`+`().")
+  val primitivePlusString = SymbolMatcher.exact(
     "scala/Byte#`+`().",
     "scala/Short#`+`().",
     "scala/Char#`+`().",
@@ -22,12 +22,18 @@ final class Any2StringAdd extends SemanticRule("fix.scala213.Any2StringAdd") {
 
   override def fix(implicit doc: SemanticDocument): Patch = {
     doc.tree.collect {
-      case plusString(Term.ApplyInfix(lhs, _, _, _)) => addToString(lhs)
+      case any2stringaddPlusString(Term.ApplyInfix(lhs, _, _, _)) => addToString(lhs)
+      case primitivePlusString(Term.ApplyInfix(lhs, _, _, _)) => blankStringPlus(lhs)
     }.asPatch
   }
 
   private def addToString(term: Term) = term match {
     case _: Term.Name | _: Term.Select | _: Term.Block => Patch.addRight(term, ".toString")
     case _ => Patch.addLeft(term, "(") + Patch.addRight(term, ").toString")
   }
+
+  private def blankStringPlus(term: Term) = term match {
+    case _: Term.Name | _: Term.Select | _: Term.Block => Patch.addLeft(term, """"" + """)
+    case _ => Patch.addLeft(term, """"" + (""") + Patch.addRight(term, ")")
+  }
 }