diff options
Diffstat (limited to 'compiler/GHC/Prelude.hs')
| -rw-r--r-- | compiler/GHC/Prelude.hs | 18 |
1 files changed, 16 insertions, 2 deletions
diff --git a/compiler/GHC/Prelude.hs b/compiler/GHC/Prelude.hs index 95c2d4b190..eb8bc31cef 100644 --- a/compiler/GHC/Prelude.hs +++ b/compiler/GHC/Prelude.hs @@ -1,5 +1,6 @@ {-# LANGUAGE CPP #-} - +{-# LANGUAGE KindSignatures #-} +{-# LANGUAGE ConstraintKinds #-} -- | Custom GHC "Prelude" -- -- This module serves as a replacement for the "Prelude" module @@ -10,7 +11,7 @@ -- * Is compiled with -XNoImplicitPrelude -- * Explicitly imports GHC.Prelude -module GHC.Prelude (module X) where +module GHC.Prelude (module X, HasDebugCallStack) where -- We export the 'Semigroup' class but w/o the (<>) operator to avoid -- clashing with the (Outputable.<>) operator which is heavily used @@ -19,6 +20,19 @@ module GHC.Prelude (module X) where import Prelude as X hiding ((<>)) import Data.Foldable as X (foldl') +import GHC.Exts (Constraint) +#if defined(DEBUG) +import GHC.Stack (HasCallStack) +#endif +-- We define + +-- | A call stack constraint, but only when 'isDebugOn'. +#if defined(DEBUG) +type HasDebugCallStack = HasCallStack +#else +type HasDebugCallStack = (() :: Constraint) +#endif + {- Note [Why do we import Prelude here?] ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ |