`scala.language.dynamics` import is "shadowed" by any other import

[propensive]

The scala.language.dynamics implicit for enabling use of the Dynamic trait appears to be strangely "shadowed" by any subsequent import.

This does not compile,

import scala.language.dynamics
import scala.List
class Foo() extends Dynamic

with

dotc test.scala

whereas omitting

import scala.List

will allow it to compile, as will reordering the imports like so,

import scala.List
import scala.language.dynamics
class Foo() extends Dynamic

Compiler version:

Dotty compiler version 0.5.0-RC1 -- Copyright 2002-2017, LAMP/EPFL

Compiler output:

-- Error: test.scala:3:6 -------------------------------------------------------
3 |class Foo() extends Dynamic
  |^^^^^^^^^^^^^^^^^^^^^^^^^^^
  |extension of type scala.Dynamic needs to be enabled
  |by making the implicit value scala.language.dynamics visible.
  |This can be achieved by adding the import clause 'import scala.language.dynamics'
  |or by setting the compiler option -language:dynamics.
  |See the Scala docs for value scala.language.dynamics for a discussion
  |why the feature needs to be explicitly enabled.
one error found