compiler: introduce custom "GhcPrelude" Prelude

This switches the compiler/ component to get compiled with
-XNoImplicitPrelude and a `import GhcPrelude` is inserted in all
modules.

This is motivated by the upcoming "Prelude" re-export of
`Semigroup((<>))` which would cause lots of name clashes in every
modulewhich imports also `Outputable`

Reviewers: austin, goldfire, bgamari, alanz, simonmar

Reviewed By: bgamari

Subscribers: goldfire, rwbarton, thomie, mpickering, bgamari

Differential Revision: https://phabricator.haskell.org/D3989

6 files changed, 11 insertions, 1 deletions

diff --git a/compiler/parser/ApiAnnotation.hs b/compiler/parser/ApiAnnotation.hs
index 34787b3399..282d3904f8 100644
--- a/compiler/parser/ApiAnnotation.hs
+++ b/compiler/parser/ApiAnnotation.hs
@@ -13,6 +13,8 @@ module ApiAnnotation (
   LRdrName -- Exists for haddocks only
   ) where
 
+import GhcPrelude
+
 import RdrName
 import Outputable
 import SrcLoc
diff --git a/compiler/parser/Ctype.hs b/compiler/parser/Ctype.hs
index 6423218f91..9c3988e869 100644
--- a/compiler/parser/Ctype.hs
+++ b/compiler/parser/Ctype.hs
@@ -16,6 +16,8 @@ module Ctype
 
 #include "HsVersions.h"
 
+import GhcPrelude
+
 import Data.Int         ( Int32 )
 import Data.Bits        ( Bits((.&.)) )
 import Data.Char        ( ord, chr )
diff --git a/compiler/parser/HaddockUtils.hs b/compiler/parser/HaddockUtils.hs
index 387cbf8f08..7969f6e1a2 100644
--- a/compiler/parser/HaddockUtils.hs
+++ b/compiler/parser/HaddockUtils.hs
@@ -1,6 +1,8 @@
 
 module HaddockUtils where
 
+import GhcPrelude
+
 import HsSyn
 import SrcLoc
 
diff --git a/compiler/parser/Lexer.x b/compiler/parser/Lexer.x
index 5d3d65d035..8c17315fb0 100644
--- a/compiler/parser/Lexer.x
+++ b/compiler/parser/Lexer.x
@@ -75,6 +75,8 @@ module Lexer (
    moveAnnotations
   ) where
 
+import GhcPrelude
+
 -- base
 import Control.Monad
 import Control.Monad.Fail as MonadFail
diff --git a/compiler/parser/Parser.y b/compiler/parser/Parser.y
index a4507fc233..d13b9c0b7f 100644
--- a/compiler/parser/Parser.y
+++ b/compiler/parser/Parser.y
@@ -83,7 +83,7 @@ import TysWiredIn       ( unitTyCon, unitDataCon, tupleTyCon, tupleDataCon, nilD
 
 -- compiler/utils
 import Util             ( looksLikePackageName )
-import Prelude
+import GhcPrelude
 
 import qualified GHC.LanguageExtensions as LangExt
 }
diff --git a/compiler/parser/RdrHsSyn.hs b/compiler/parser/RdrHsSyn.hs
index 41d8a4a339..4eabb66b43 100644
--- a/compiler/parser/RdrHsSyn.hs
+++ b/compiler/parser/RdrHsSyn.hs
@@ -67,6 +67,8 @@ module   RdrHsSyn (
 
     ) where
 
+import GhcPrelude
+
 import HsSyn            -- Lots of it
 import Class            ( FunDep )
 import TyCon            ( TyCon, isTupleTyCon, tyConSingleDataCon_maybe )