`OverloadedLabels` is a simple enough extension to parse and format. It
is becoming more common with use of `generic-lens`. Since it can be
treated as a `HsVar` its implementation only requires using `docLit`,
along with some marshalling for dealing with `FastString`.
Previously, we could only import a type operator with no subsequent
list, i.e.
import Foo ( (:.) )
was fine, but
import Foo ( (:.)(..) )
import Foo ( (:.)((:.) )
import Foo ( (:.)(A, b) )
would all break. Brittany would attempt to output them as
import Foo ( :.(..) )
import Foo ( :.((:.) )
import Foo ( :.(A, b) )
I believe the problem was that although `ieName <$> lie` was returning
an `IEWrappedName` with the same contents as used in `layoutWrapped`,
it had different location annotations; and the parentheses are
apparently saved in the location annotations.
pepe iborra
Evan Borden
Lennart Spitzner
Phil Hazelden