Quickcheck warns about commented-out properties

Applies to ver. 2.8.1

{-# LANGUAGE TemplateHaskell #-}
import Test.QuickCheck
import Test.QuickCheck.All
{-
prop_old_freeVars_Term conf x = True
-}
-- Template Haskell hack to make the following $quickCheckAll work under ghc-7.8.
return [] 
-- | All tests as collected by 'quickCheckAll'.
tests :: IO Bool
tests = do
  putStrLn "Agda.TypeChecking.Free.Tests"
  $quickCheckAll

gives warning

/home/abel/agda/src/full/Agda/TypeChecking/Free/Tests.hs:129:3: Warning:
    Name prop_old_freeVars_Term found in source file but was not in scope

which turns into error with -Werror

Reproduce the Haskell example with Test.QuickCheck.All and quickCheckAll under -Werror. Trace how quickCheckAll handles names found in source but not in scope; done means the commented-out prop_old_freeVars_Term no longer produces the warning while active properties continue to be collected.