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

1 files changed, 2 insertions, 0 deletions

diff --git a/compiler/simplCore/CallArity.hs b/compiler/simplCore/CallArity.hs
index e41e5bdef9..0e6cf70ba6 100644
--- a/compiler/simplCore/CallArity.hs
+++ b/compiler/simplCore/CallArity.hs
@@ -7,6 +7,8 @@ module CallArity
     , callArityRHS -- for testing
     ) where
 
+import GhcPrelude
+
 import VarSet
 import VarEnv
 import DynFlags ( DynFlags )