This question still remains unanswered, although it has been marked as a duplicate.
From http://www.scala-lang.org/files/archive/spec/2.12/08-pattern-matching.html#type-patterns we can write the following code
Suppose I have a class like:
trait T[A] { def getType: String } object T { def apply[A](implicit t: T[A]): T[A] = t implicit object TInt extends T[Int] { def getType = "Int" } implicit object TString extends T[String] { def getType = "String" } }
and a typed class that uses a type class
class C[A] { def func(implicit t: T[A]) = t.getType }
When I try to type C[A] , I get an error
val list: List[Int] = 1 :: 2 :: Nil val result = list match { case list: List[t] => new C[t]
What, in this case, is the incorrect use of the type parameter in comparison with the pattern?
Updated Another simple example:
val array = List[Int](1, 2, 3, 4) match { case l: List[a] => scala.collection.mutable.ArrayBuffer[a]() } array += 1
Error: type mismatch; found: Int(1), required: a array += 1 type mismatch; found: Int(1), required: a array += 1
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