If I say

{-# LANGUAGE GADTs, TypeApplications, TypeInType #-}

module Bug where

import Type.Reflection

data G a where
  MkG :: a ~ Bool => G a

rep = typeRep @MkG

I get

Bug.hs:10:7: error:
    • No instance for (Typeable <>) arising from a use of ‘typeRep’
    • In the expression: typeRep @MkG
      In an equation for ‘rep’: rep = typeRep @MkG
   |
10 | rep = typeRep @MkG
   |   

First off, the error message is confusing, mentioning the mysterious <>. But more importantly, it would be nice if the Typeable mechanism supported coercions.