Handle --no-prelude flag in the Metadata.Prelude module rather than distributed across many modules

Good in case the meaning of —no-prelude changes

compiler/Build/Source.hs

@@ -26,7 +26,7 @@ import qualified Transform.Canonicalize as Canonical
 
 build :: Bool -> Interfaces -> String -> Either [Doc] MetadataModule
 build noPrelude interfaces source =
-  do let add = if noPrelude then id else Prelude.add
+  do let add = Prelude.add noPrelude
          infixes = Map.fromList . map (\(assoc,lvl,op) -> (op,(lvl,assoc)))
                  . concatMap iFixities $ Map.elems interfaces
 

compiler/Compiler.hs

@@ -31,7 +31,7 @@ compileArgs flags =
 build :: Flag.Flags -> FilePath -> IO ()
 build flags rootFile =
     do let noPrelude = Flag.no_prelude flags
-       builtIns <- if noPrelude then return Map.empty else Prelude.interfaces
+       builtIns <- Prelude.interfaces noPrelude
 
        files <- if Flag.make flags
                 then getSortedDependencies (Flag.src_dir flags) builtIns rootFile

compiler/Elm/Internal/Utils.hs

@@ -21,7 +21,7 @@ compile source =
 
 {-# NOINLINE interfaces #-}
 interfaces :: M.Interfaces
-interfaces = unsafePerformIO $ Prelude.interfaces
+interfaces = unsafePerformIO $ Prelude.interfaces False
 
 -- |This function extracts the module name of a given source program.
 moduleName :: String -> Maybe String

compiler/Metadata/Prelude.hs

@@ -13,10 +13,10 @@ import qualified Data.ByteString.Lazy as BS
 
 import qualified InterfaceSerialization as IS
 
-add :: Module def -> Module def
-add (Module name exs ims decls) = Module name exs (customIms ++ ims) decls
+add :: Bool -> Module def -> Module def
+add noPrelude (Module name exs ims decls) = Module name exs (customIms ++ ims) decls
     where
-      customIms = concatMap addModule prelude
+      customIms = if noPrelude then [] else concatMap addModule prelude
 
       addModule (n, method) = case lookup n ims of
                                 Nothing     -> [(n, method)]
@@ -30,8 +30,10 @@ prelude = text ++ map (\n -> (n, Hiding [])) modules
     modules = [ "Basics", "Signal", "List", "Maybe", "Time", "Prelude"
               , "Graphics.Element", "Color", "Graphics.Collage" ]
 
-interfaces :: IO Interfaces
-interfaces = safeReadDocs =<< Path.getDataFileName "interfaces.data"
+interfaces :: Bool -> IO Interfaces
+interfaces noPrelude =
+    do ifaces <- safeReadDocs =<< Path.getDataFileName "interfaces.data"
+       return $ if noPrelude then Map.empty else ifaces
 
 safeReadDocs :: FilePath -> IO Interfaces
 safeReadDocs name =