Postfix operator notation:
val s = 123 toString
Reflective call:
def foo(v: {def bar()}) = v.bar()
Dynamic member selection:
class Foo extends Dynamic
Implicit conversion:
implicit def toInt(s: String) = s.toInt
Higher-kinded type:
class Bar[M[A]]
Existential type:
def foo(v: Seq[T] forSome { type T })
Macro definition:
def assert(s: String) = macro Asserts.assertImpl
Scala compiler may also emit these warnings when "-feature" option is provided.
See: Project Settings / Compiler / Scala Compiler / Features
Since: Scala 2.10