Clean up boot vs non-boot disambiguating types

We often have (ModuleName, Bool) or (Module, Bool) pairs for "extended"
module names (without or with a unit id) disambiguating boot and normal
modules. We think this is important enough across the compiler that it
deserves a new nominal product type. We do this with synnoyms and a
functor named with a `Gen` prefix, matching other newly created
definitions.

It was also requested that we keep custom `IsBoot` / `NotBoot` sum type.
So we have it too. This means changing many the many bools to use that
instead.

Updates `haddock` submodule.

2 files changed, 21 insertions, 17 deletions

diff --git a/compiler/GHC/Iface/Load.hs b/compiler/GHC/Iface/Load.hs
index 80c4505c8e..ef69e97605 100644
--- a/compiler/GHC/Iface/Load.hs
+++ b/compiler/GHC/Iface/Load.hs
@@ -366,7 +366,7 @@ loadSysInterface doc mod_name = loadInterfaceWithException doc mod_name ImportBy
 ------------------
 -- | Loads a user interface and throws an exception if it fails. The first parameter indicates
 -- whether we should import the boot variant of the module
-loadUserInterface :: Bool -> SDoc -> Module -> IfM lcl ModIface
+loadUserInterface :: IsBootInterface -> SDoc -> Module -> IfM lcl ModIface
 loadUserInterface is_boot doc mod_name
   = loadInterfaceWithException doc mod_name (ImportByUser is_boot)
 
@@ -485,7 +485,7 @@ loadInterface doc_str mod from
                               }
                }
 
-        ; let bad_boot = mi_boot iface && fmap fst (if_rec_types gbl_env) == Just mod
+        ; let bad_boot = mi_boot iface == IsBoot && fmap fst (if_rec_types gbl_env) == Just mod
                             -- Warn warn against an EPS-updating import
                             -- of one's own boot file! (one-shot only)
                             -- See Note [Loading your own hi-boot file]
@@ -690,7 +690,7 @@ moduleFreeHolesPrecise doc_str mod
             Just ifhs  -> Just (renameFreeHoles ifhs insts)
             _otherwise -> Nothing
     readAndCache imod insts = do
-        mb_iface <- findAndReadIface (text "moduleFreeHolesPrecise" <+> doc_str) imod mod False
+        mb_iface <- findAndReadIface (text "moduleFreeHolesPrecise" <+> doc_str) imod mod NotBoot
         case mb_iface of
             Succeeded (iface, _) -> do
                 let ifhs = mi_free_holes iface
@@ -706,23 +706,25 @@ wantHiBootFile :: DynFlags -> ExternalPackageState -> Module -> WhereFrom
 wantHiBootFile dflags eps mod from
   = case from of
        ImportByUser usr_boot
-          | usr_boot && not this_package
+          | usr_boot == IsBoot && not this_package
           -> Failed (badSourceImport mod)
           | otherwise -> Succeeded usr_boot
 
        ImportByPlugin
-          -> Succeeded False
+          -> Succeeded NotBoot
 
        ImportBySystem
           | not this_package   -- If the module to be imported is not from this package
-          -> Succeeded False   -- don't look it up in eps_is_boot, because that is keyed
+          -> Succeeded NotBoot -- don't look it up in eps_is_boot, because that is keyed
                                -- on the ModuleName of *home-package* modules only.
                                -- We never import boot modules from other packages!
 
           | otherwise
           -> case lookupUFM (eps_is_boot eps) (moduleName mod) of
-                Just (_, is_boot) -> Succeeded is_boot
-                Nothing           -> Succeeded False
+                Just (GWIB { gwib_isBoot = is_boot }) ->
+                  Succeeded is_boot
+                Nothing ->
+                  Succeeded NotBoot
                      -- The boot-ness of the requested interface,
                      -- based on the dependencies in directly-imported modules
   where
@@ -899,7 +901,7 @@ findAndReadIface :: SDoc
         -- sometimes it's ok to fail... see notes with loadInterface
 findAndReadIface doc_str mod wanted_mod_with_insts hi_boot_file
   = do traceIf (sep [hsep [text "Reading",
-                           if hi_boot_file
+                           if hi_boot_file == IsBoot
                              then text "[boot]"
                              else Outputable.empty,
                            text "interface for",
@@ -1219,11 +1221,11 @@ pprDeps (Deps { dep_mods = mods, dep_pkgs = pkgs, dep_orphs = orphs,
           text "family instance modules:" <+> fsep (map ppr finsts)
         ]
   where
-    ppr_mod (mod_name, boot) = ppr mod_name <+> ppr_boot boot
+    ppr_mod (GWIB { gwib_mod = mod_name, gwib_isBoot = boot }) = ppr mod_name <+> ppr_boot boot
     ppr_pkg (pkg,trust_req)  = ppr pkg <>
                                (if trust_req then text "*" else Outputable.empty)
-    ppr_boot True  = text "[boot]"
-    ppr_boot False = Outputable.empty
+    ppr_boot IsBoot  = text "[boot]"
+    ppr_boot NotBoot = Outputable.empty
 
 pprFixities :: [(OccName, Fixity)] -> SDoc
 pprFixities []    = Outputable.empty
diff --git a/compiler/GHC/Iface/Recomp.hs b/compiler/GHC/Iface/Recomp.hs
index 68103fc1f4..03223c5712 100644
--- a/compiler/GHC/Iface/Recomp.hs
+++ b/compiler/GHC/Iface/Recomp.hs
@@ -252,7 +252,7 @@ checkVersions hsc_env mod_summary iface
   where
     this_pkg = thisPackage (hsc_dflags hsc_env)
     -- This is a bit of a hack really
-    mod_deps :: ModuleNameEnv (ModuleName, IsBootInterface)
+    mod_deps :: ModuleNameEnv ModuleNameWithIsBoot
     mod_deps = mkModDeps (dep_mods (mi_deps iface))
 
 -- | Check if any plugins are requesting recompilation
@@ -455,7 +455,7 @@ checkDependencies hsc_env summary iface
      case find_res of
         Found _ mod
           | pkg == this_pkg
-           -> if moduleName mod `notElem` map fst prev_dep_mods ++ prev_dep_plgn
+           -> if moduleName mod `notElem` map gwib_mod prev_dep_mods ++ prev_dep_plgn
                  then do traceHiDiffs $
                            text "imported module " <> quotes (ppr mod) <>
                            text " not among previous dependencies"
@@ -474,7 +474,9 @@ checkDependencies hsc_env summary iface
            where pkg = moduleUnit mod
         _otherwise  -> return (RecompBecause reason)
 
-   old_deps = Set.fromList $ map fst $ filter (not . snd) prev_dep_mods
+   projectNonBootNames = map gwib_mod . filter ((== NotBoot) . gwib_isBoot)
+   old_deps = Set.fromList
+     $ projectNonBootNames prev_dep_mods
    isOldHomeDeps = flip Set.member old_deps
    checkForNewHomeDependency (L _ mname) = do
      let
@@ -489,7 +491,7 @@ checkDependencies hsc_env summary iface
        then return (UpToDate, [])
        else do
          mb_result <- getFromModIface "need mi_deps for" mod $ \imported_iface -> do
-           let mnames = mname:(map fst $ filter (not . snd) $
+           let mnames = mname:(map gwib_mod $ filter ((== NotBoot) . gwib_isBoot) $
                  dep_mods $ mi_deps imported_iface)
            case find (not . isOldHomeDeps) mnames of
              Nothing -> return (UpToDate, mnames)
@@ -1073,7 +1075,7 @@ getOrphanHashes hsc_env mods = do
 
 sortDependencies :: Dependencies -> Dependencies
 sortDependencies d
- = Deps { dep_mods   = sortBy (compare `on` (moduleNameFS.fst)) (dep_mods d),
+ = Deps { dep_mods   = sortBy (compare `on` (moduleNameFS . gwib_mod)) (dep_mods d),
           dep_pkgs   = sortBy (compare `on` fst) (dep_pkgs d),
           dep_orphs  = sortBy stableModuleCmp (dep_orphs d),
           dep_finsts = sortBy stableModuleCmp (dep_finsts d),