data Truth = True | False

ifThenElse :: Truth -> a -> a -> a

ifThenElse True x _ = x

ifThenElse False _ x = x

(==) :: a -> a -> Truth

(==) = ...

I'm replacing Bool with my own Truth type.  Clients will be built with RebindableSyntax, so that they will use these definitions for desugaring.

However, if I write this:

f :: Text -> Text

f "r" = "rrr"

f other = other

I get a build error indicating that GHC expected the (==) operator to return a value of type Bool, rather than Truth.

Shouldn't pattern matching desugar to use overloaded ifThenElse in these situations?  Or is it expected that use of GHC.Types.Bool is hard-coded even with RebindableSyntax enabled?

Thanks,

Chris