magnify :: forall outertag innertag t outer inner m a.
  ( forall x. Coercible (t m x) (m x)
  , forall m'. HasReader outertag outer m'
    => HasReader innertag inner (t m')
  , HasReader outertag outer m )
  => (forall m'. HasReader innertag inner m' => m' a) -> m a