SeqLike containsTyped

Author: cvogt

src/main/scala/collection.scala

@@ -6,6 +6,10 @@ import scala.collection.mutable.Builder
 
 
 object `package`{
+ implicit class SeqLikeExtensions[A, Repr](val coll: SeqLike[A, Repr]) extends AnyVal{
+ /** type-safe contains check */
+ def containsTyped(t: A) = coll.contains(t)
+ }
  implicit class TraversableLikeExtensions[A, Repr](val coll: TraversableLike[A, Repr]) extends AnyVal{
  /** Eliminates duplicates based on the given key function.
  There is no guarantee which elements stay in case element two elements result in the same key.

src/test/scala/collection.scala

@@ -9,6 +9,15 @@ case class Person(name: String, age: Int)
 object chris extends Person("Chris",99)
 object marcos extends Person("Marcos",99)
 class CollectionTest extends FunSuite{
+ test("SeqLike containsTyped"){
+ val s = Seq(1)
+ assert( s contains 1 )
+ assert( s containsTyped 1 )
+ assert( !(s contains 2) )
+ assert( !(s containsTyped 2) )
+ assert( !(s contains "asdf") )
+ assertTypeError( """ !(s containsTyped "asdf") """ )
+ }
  test("distinctBy"){
  val ps = List(
  chris,