Merge branch 'main' into main

zio-schema/shared/src/main/scala-3/zio/schema/package.scala

@@ -1,5 +1,27 @@
 package zio
 
+import scala.reflect.ClassTag
+
 package object schema {
   type Singleton = scala.Singleton
+
+  extension [A: ClassTag, B: ClassTag] (s: Schema.Fallback[A, B])
+    def merge: Schema[A | B] =
+      s.transform(_.merge, {
+        case left: A  => Fallback.Left(left.asInstanceOf[A])
+        case right: B => Fallback.Right(right.asInstanceOf[B])
+      })
+
+  extension [A: ClassTag] (s: Schema[A])
+    def orElse[B: ClassTag](s0: Schema[B]): Schema[A | B] =
+      Schema.Fallback(s, s0).merge
+
+  extension [A: ClassTag, B: ClassTag] (fallback: Fallback[A, B])
+    def merge: A | B =
+      fallback match {
+        case Fallback.Left(left) => left
+        case Fallback.Right(right) => right
+        case Fallback.Both(left, _) => left
+      }
+
 }