t5152.scala:7: error: kinds of the type arguments (Test.B) do not conform to the expected kinds of the type parameters (type E) in class A.
Test.B's type parameters do not match type E's expected parameters:
type E has one type parameter, but type _ has none
  class B[E[_]] extends A[B] { }  // B is depth 2 but A requires 1
                        ^
t5152.scala:11: error: kinds of the type arguments (Test.B1) do not conform to the expected kinds of the type parameters (type E) in class A1.
Test.B1's type parameters do not match type E's expected parameters:
type _ has no type parameters, but type G has one
  class B1[E[_]] extends A1[B1]   // B1 is depth 2 but A1 requires 3
                         ^
two errors found