Only doctests on immediate module

If I have three modules:

-- A.hs
module A where
-- $
-- >>> True
-- True

-- B.hs
module B where
import A
-- $
-- >>> True
-- True

-- C.hs
module C where
import B
-- $
-- >>> True
-- True

Running doctest C.hs will run all the doctests in all three files.

$ doctest C.hs
Examples: 3  Tried: 3  Errors: 0  Failures: 0

Is there a way to run doctest on only the top-level module - that is, have it not recursively search for tests in included modules?