Different behavior of Manifest on classes vs. their type alias

Question
1

In an effort to apply Manifest on a Higher-kinded-type, we notice the difference between Seq and Option, then the type alias Seq and the direct class scala.collection.Seq.

scala> class MyType[F[_]]
warning: there was one feature warning; re-run with -feature for details
defined class MyType

scala> def bar[T: Manifest](t: T) = {}
bar: [T](t: T)(implicit evidence$1: Manifest[T])Unit

scala> bar(new MyType[Seq])
<console>:14: error: No Manifest available for MyType[Seq].
       bar(new MyType[Seq])
          ^

scala> bar(new MyType[Option])
<console>:14: error: kinds of the type arguments (Option) do not conform to the expected kinds of the type parameters (type T).
Option's type parameters do not match type T's expected parameters:
class Option has one type parameter, but type T has none
       bar(new MyType[Option])
          ^

scala> bar(new MyType[scala.collection.Seq])
<console>:14: error: kinds of the type arguments (Seq) do not conform to the expected kinds of the type parameters (type T).
Seq's type parameters do not match type T's expected parameters:
trait Seq has one type parameter, but type T has none
       bar(new MyType[scala.collection.Seq])

I’m curious about why and the underlying mechanism, thanks!

2

Manifest is known to have such limitations.
First, try to design your signatures such that you do not need Manifest, nor ClassTag, nor TypeTag.
Note however that in some situations ClassTag is a good practice.
Otherwise try to use TypeTag in the above case.