Types are not normalized in instance declarations

Consider the example below. It does not compile, but replacing 5*2 by 10 makes it compile. This is quite annoying since it forces me to do the normalization that the computer is really much better at doing.

module NatInstance where
import GHC.TypeLits

type N = 5 * 2
data D (n :: Nat) = D
instance Show (D N) where show _ = ""

Trac metadata

Trac field	Value
Version	8.0.1
Type	Bug
TypeOfFailure	OtherFailure
Priority	normal
Resolution	Unresolved
Component	Compiler
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