Closed type families don't reduce on data family instances

The following code doesn't compile:

{-# LANGUAGE TypeFamilies #-}
module Tmp where

data family D a
data instance D () = D

type family T a where
  T () = ()
  T a = Char

try :: T (D ()) ~ Char => ()
try = ()

main :: IO ()
main = return try

giving

Tmp.hs:15:15:
    Couldn't match expected type ‘Char’ with actual type ‘T (D ())’
    In the first argument of ‘return’, namely ‘try’
    In the expression: return try
    In an equation for ‘main’: main = return try

Is this a known limitation of closed type families?

Trac metadata

Trac field	Value
Version	7.10.2
Type	Bug
TypeOfFailure	OtherFailure
Priority	normal
Resolution	Unresolved
Component	Compiler
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