Appease scalastyle

Author: andyscott

core/src/main/scala/cats/arrow/FunctionK.scala

@@ -43,15 +43,19 @@ object FunctionKMacros extends MacroCompat {
     f: c.Expr[(F[α] ⇒ G[α]) forSome { type α }]
   )(
     implicit evF: c.WeakTypeTag[F[_]], evG: c.WeakTypeTag[G[_]]
-  ): c.Expr[FunctionK[F, G]] = {
+  ): c.Expr[FunctionK[F, G]] =
+    c.Expr[FunctionK[F, G]](new Lifter[c.type ](c).lift[F, G](f.tree))
+    // ^^note: extra space after c.type to appease scalastyle
+
+  private[this] class Lifter[C <: Context](val c: C) {
     import c.universe._
 
-    def unblock(tree: Tree): Tree = tree match {
+    private[this] def unblock(tree: Tree): Tree = tree match {
       case Block(Nil, expr) ⇒ expr
       case _                ⇒ tree
     }
 
-    def punchHole(tpe: Type): Tree = tpe match {
+    private[this] def punchHole(tpe: Type): Tree = tpe match {
       case PolyType(undet :: Nil, underlying: TypeRef) ⇒
         val α = compatNewTypeName(c, "α")
         def rebind(typeRef: TypeRef): Tree =
@@ -71,29 +75,28 @@ object FunctionKMacros extends MacroCompat {
         c.abort(c.enclosingPosition, s"Unexpected type $tpe when lifting to FunctionK")
     }
 
-    val tree = unblock(f.tree) match {
-      case q"""($param) => $trans[..$typeArgs](${ arg: Ident })""" if param.name == arg.name ⇒
-
-        typeArgs
-          .collect { case tt: TypeTree => tt }
-          .find(_.original != null)
-          .foreach { param => c.abort(param.pos,
-            s"type parameter $param must not be supplied when lifting function $trans to FunctionK")
+    def lift[F[_], G[_]](tree: Tree)(implicit evF: c.WeakTypeTag[F[_]], evG: c.WeakTypeTag[G[_]]): Tree =
+      unblock(tree) match {
+        case q"""($param) => $trans[..$typeArgs](${ arg: Ident })""" if param.name == arg.name ⇒
+          typeArgs
+            .collect { case tt: TypeTree => tt }
+            .find(tt => Option(tt.original).isDefined)
+            .foreach { param => c.abort(param.pos,
+              s"type parameter $param must not be supplied when lifting function $trans to FunctionK")
           }
 
-        val F = punchHole(evF.tpe)
-        val G = punchHole(evG.tpe)
+          val F = punchHole(evF.tpe)
+          val G = punchHole(evG.tpe)
 
-        q"""
+          q"""
           new FunctionK[$F, $G] {
             def apply[A](fa: $F[A]): $G[A] = $trans(fa)
           }
          """
-      case other ⇒
-        c.abort(other.pos, s"Unexpected tree $other when lifting to FunctionK")
-    }
+        case other ⇒
+          c.abort(other.pos, s"Unexpected tree $other when lifting to FunctionK")
+      }
 
-    c.Expr[FunctionK[F, G]](tree)
   }
 
 }