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POType equality in the Scala 2.10 Reflection API
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copied!<p>I'm running into a weird issue with reflection in <a href="http://www.scala-lang.org/node/12702" rel="noreferrer">Scala 2.10.0 Milestone 4</a> that I can't wrap my head around. First for the stuff that works the way I'd expect:</p> <pre><code>scala> import scala.reflect.runtime.universe._ import scala.reflect.runtime.universe._ scala> trait A[X]; trait B[Y] extends A[Y] defined trait A defined trait B scala> typeOf[B[String]].parents res0: List[reflect.runtime.universe.Type] = List(java.lang.Object, A[String]) scala> typeOf[B[String]].parents contains typeOf[A[String]] res1: Boolean = true </code></pre> <p>Similarly (in the same session):</p> <pre><code>scala> trait D; trait E extends A[D] defined trait D defined trait E scala> typeOf[E].parents res2: List[reflect.runtime.universe.Type] = List(java.lang.Object, A[D]) scala> typeOf[E].parents contains typeOf[A[D]] res3: Boolean = true </code></pre> <p>No surprises here: I can ask for a type's parents and get exactly what I expect. Now I essentially combine the two examples above:</p> <pre><code>scala> trait F extends A[String] defined trait F scala> typeOf[F].parents res4: List[reflect.runtime.universe.Type] = List(java.lang.Object, A[String]) scala> typeOf[F].parents contains typeOf[A[String]] res5: Boolean = false </code></pre> <p>I don't understand how this could be false. The same thing happens if I have <code>F</code> extend <code>A[Seq[D]]</code>, <code>A[Int]</code>, etc. What's the generalization I'm missing that would make this behavior make sense?</p>

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