Demonstrate the problem (FasterXML/jackson-module-scala#366)

.gitignore

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+/.idea
+/target
+/project/target
+

build.sbt

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+name := "JacksonTypeAlias"
+
+version := "0.1"
+
+scalaVersion := "2.11.12"
+
+
+val jacksonVersion = "2.9.6"
+
+libraryDependencies += "com.fasterxml.jackson.core" % "jackson-databind" % jacksonVersion
+
+libraryDependencies += "com.fasterxml.jackson.module" %% "jackson-module-scala" % jacksonVersion
+
+libraryDependencies += "com.fasterxml.jackson.dataformat" % "jackson-dataformat-yaml" % jacksonVersion

project/build.properties

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+sbt.version = 1.1.6

src/main/scala/mypackage/Main.scala

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+package mypackage
+
+import com.fasterxml.jackson.databind.ObjectMapper
+import com.fasterxml.jackson.module.scala.DefaultScalaModule
+import com.fasterxml.jackson.module.scala.experimental.ScalaObjectMapper
+
+case class XY(x: Double = 0, y: Double = 0)
+
+trait Abstract {
+  type Vector2f
+
+  trait ConstructVector2f {
+    def apply(x: Double, y: Double): Vector2f
+  }
+  implicit val Vector2f: ConstructVector2f
+}
+
+object Concrete extends Abstract {
+  type Vector2f = XY
+  object Vector2f extends ConstructVector2f {
+    def apply(x: Double, y: Double) = XY(x, y)
+  }
+}
+
+object Abstract {
+  val Link: Abstract = Concrete
+}
+
+import Abstract.Link.Vector2f
+
+case class Container(from: Vector2f)
+
+object Main extends App {
+
+  val mapper = new ObjectMapper with ScalaObjectMapper
+
+  mapper.registerModule(DefaultScalaModule)
+
+  val input = Container(Vector2f(0,0))
+
+  val out = mapper.writeValueAsString(input)
+
+  val loaded = mapper.readValue[Container](out)
+
+  val xy: Vector2f = loaded.from
+
+  println(loaded) // prints "Container(Map(x -> 0.0, y -> 0.0))" instead of "Container(XY(0.0,0.0))"
+  assert(xy.isInstanceOf[XY]) // fails
+}