Add Show (AsType a) instance

Author: carbolymer

cardano-api/src/Cardano/Api/HasTypeProxy.hs

@@ -15,8 +15,7 @@ where
 import Data.ByteString qualified as BS
 import Data.ByteString.Lazy qualified as BSL
 import Data.Kind (Constraint, Type)
-import Data.Proxy (Proxy (..))
-import Data.Typeable (Typeable)
+import Data.Typeable
 import Data.Word (Word16, Word8)
 import Numeric.Natural (Natural)
 
@@ -29,6 +28,13 @@ class Typeable t => HasTypeProxy t where
 
   proxyToAsType :: Proxy t -> AsType t
 
+-- | Generalised show instance for all singletons of 'AsType' displaying the type.
+instance Typeable t => Show (AsType t) where
+  show = show . typeRep . proxy
+   where
+    proxy :: AsType t -> Proxy t
+    proxy _ = Proxy
+
 instance HasTypeProxy Word8 where
   data AsType Word8 = AsWord8
   proxyToAsType _ = AsWord8