From https://github.com/plow-technologies/quickcheck-arbitrary-template/pull/11
From: Xavier Dectot <xavier@wheredoibegin.fr>
Date: Fri, 21 Mar 2025 09:32:13 +0100
Subject: [PATCH] porting to recent template-haskell

--- a/src/Test/QuickCheck/TH/Generators/Internal.hs
+++ b/src/Test/QuickCheck/TH/Generators/Internal.hs
@@ -40,7 +40,7 @@ $(buildArbAny 20)
 -- type constructor must be either a data type or a newtype. Any other
 -- value will result in an exception.
 withType :: Name
-         -> ([TyVarBndr] -> [Con] -> Q a)
+         -> ([TyVarBndr BndrVis] -> [Con] -> Q a)
          -- ^ Function that generates the actual code. Will be applied
          -- to the type variable binders and constructors extracted
          -- from the given 'Name'.
--- a/src/Test/QuickCheck/TH/Generators/Internal/BuildArbitrary.hs
+++ b/src/Test/QuickCheck/TH/Generators/Internal/BuildArbitrary.hs
@@ -51,7 +51,7 @@ buildArbAny l
       Nothing -> return []
       Just (firstArbParameterName,restArbParameterNames,arbitraryTypeName,genTypeName,fmapName,apName,arbitraryValue) -> do
         -- all of the variables in the function to be created, input and output
-        let plainTVs = PlainTV <$> (arbParameterNames ++ [bName])
+        let plainTVs = flip PlainTV SpecifiedSpec <$> (arbParameterNames ++ [bName])
             -- Arbitrary type instance required for all vars in arbParameterNames
             typeClassRequirements = (AppT (ConT arbitraryTypeName) ) <$> (VarT <$> arbParameterNames)
             genB     = AppT (ConT genTypeName) (VarT bName)