Add formatters for Option & Map

compiler/src/dotty/tools/dotc/printing/Formatting.scala

@@ -54,10 +54,22 @@ object Formatting {
     object Show extends ShowImplicits1:
       inline def apply[A](using inline z: Show[A]): Show[A] = z
 
+      given [X: Show]: Show[Option[X]] with
+        def show(x: Option[X]) = new CtxShow:
+          def run(using Context) = x match
+            case Some(x) => i"Some($x)"
+            case None    => "None"
+      end given
+
       given [X: Show]: Show[Seq[X]] with
         def show(x: Seq[X]) = new CtxShow:
           def run(using Context) = x.map(show1)
 
+      given [X: Show, Y: Show]: Show[Map[X, Y]] with
+        def show(x: Map[X, Y]) = new CtxShow:
+          def run(using Context) = x.map((x, y) => i"$x => $y")
+      end given
+
       given [H: Show, T <: Tuple: Show]: Show[H *: T] with
         def show(x: H *: T) = new CtxShow:
           def run(using Context) = show1(x.head) *: Show[T].show(x.tail).ctxShow.asInstanceOf[Tuple]