+importsFromImportDecl :: Module
+ -> LImportDecl RdrName
+ -> RnM (GlobalRdrEnv, ImportAvails)
+
+importsFromImportDecl this_mod
+ (L loc (ImportDecl loc_imp_mod_name want_boot qual_only as_mod imp_details))
+ =
+ addSrcSpan loc $
+
+ -- If there's an error in loadInterface, (e.g. interface
+ -- file not found) we get lots of spurious errors from 'filterImports'
+ let
+ imp_mod_name = unLoc loc_imp_mod_name
+ this_mod_name = moduleName this_mod
+ doc = ppr imp_mod_name <+> ptext SLIT("is directly imported")
+ in
+ loadSrcInterface doc imp_mod_name want_boot `thenM` \ iface ->
+
+ -- Compiler sanity check: if the import didn't say
+ -- {-# SOURCE #-} we should not get a hi-boot file
+ WARN( not want_boot && mi_boot iface, ppr imp_mod_name )
+
+ -- Issue a user warning for a redundant {- SOURCE -} import
+ -- NB that we arrange to read all the ordinary imports before
+ -- any of the {- SOURCE -} imports
+ warnIf (want_boot && not (mi_boot iface))
+ (warnRedundantSourceImport imp_mod_name) `thenM_`
+
+ let
+ imp_mod = mi_module iface
+ deprecs = mi_deprecs iface
+ is_orph = mi_orphan iface
+ deps = mi_deps iface
+
+ filtered_exports = filter not_this_mod (mi_exports iface)
+ not_this_mod (mod,_) = mod /= this_mod_name
+ -- If the module exports anything defined in this module, just ignore it.
+ -- Reason: otherwise it looks as if there are two local definition sites
+ -- for the thing, and an error gets reported. Easiest thing is just to
+ -- filter them out up front. This situation only arises if a module
+ -- imports itself, or another module that imported it. (Necessarily,
+ -- this invoves a loop.)
+ --
+ -- Tiresome consequence: if you say
+ -- module A where
+ -- import B( AType )
+ -- type AType = ...
+ --
+ -- module B( AType ) where
+ -- import {-# SOURCE #-} A( AType )
+ --
+ -- then you'll get a 'B does not export AType' message. Oh well.
+
+ qual_mod_name = case as_mod of
+ Nothing -> imp_mod_name
+ Just another_name -> another_name
+ imp_spec = ImportSpec { is_mod = imp_mod_name, is_qual = qual_only,
+ is_loc = loc, is_as = qual_mod_name }
+ in
+
+ -- Get the total imports, and filter them according to the import list
+ exportsToAvails filtered_exports `thenM` \ total_avails ->
+ filterImports iface imp_spec
+ imp_details total_avails `thenM` \ (avail_env, gbl_env) ->
+
+ let
+ -- Compute new transitive dependencies
+ orphans | is_orph = insert imp_mod_name (dep_orphs deps)
+ | otherwise = dep_orphs deps
+
+ (dependent_mods, dependent_pkgs)
+ | isHomeModule imp_mod
+ = -- Imported module is from the home package
+ -- Take its dependent modules and
+ -- (a) remove this_mod (might be there as a hi-boot)
+ -- (b) add imp_mod itself
+ -- Take its dependent packages unchanged
+ ((imp_mod_name, want_boot) : filter not_self (dep_mods deps), dep_pkgs deps)
+
+ | otherwise
+ = -- Imported module is from another package
+ -- Dump the dependent modules
+ -- Add the package imp_mod comes from to the dependent packages
+ -- from imp_mod
+ ([], insert (mi_package iface) (dep_pkgs deps))
+
+ not_self (m, _) = m /= this_mod_name
+
+ import_all = case imp_details of
+ Just (is_hiding, ls) -- Imports are spec'd explicitly
+ | not is_hiding -> Just (not (null ls))
+ _ -> Nothing -- Everything is imported,
+ -- (or almost everything [hiding])
+
+ -- unqual_avails is the Avails that are visible in *unqualified* form
+ -- We need to know this so we know what to export when we see
+ -- module M ( module P ) where ...
+ -- Then we must export whatever came from P unqualified.
+ imports = ImportAvails {
+ imp_qual = unitModuleEnvByName qual_mod_name avail_env,
+ imp_env = avail_env,
+ imp_mods = unitModuleEnv imp_mod (imp_mod, import_all),
+ imp_orphs = orphans,
+ imp_dep_mods = mkModDeps dependent_mods,
+ imp_dep_pkgs = dependent_pkgs }
+
+ in
+ -- Complain if we import a deprecated module
+ ifOptM Opt_WarnDeprecations (
+ case deprecs of
+ DeprecAll txt -> addWarn (moduleDeprec imp_mod_name txt)
+ other -> returnM ()
+ ) `thenM_`
+
+ returnM (gbl_env, imports)
+
+exportsToAvails :: [IfaceExport] -> TcRnIf gbl lcl Avails
+exportsToAvails exports
+ = do { avails_by_module <- mappM do_one exports
+ ; return (concat avails_by_module) }
+ where
+ do_one (mod_name, exports) = mapM (do_avail mod_name) exports
+ do_avail mod_nm (Avail n) = do { n' <- lookupOrig mod_nm n;
+ ; return (Avail n') }
+ do_avail mod_nm (AvailTC n ns) = do { n' <- lookupOrig mod_nm n
+ ; ns' <- mappM (lookup_sub n') ns
+ ; return (AvailTC n' ns') }
+ where
+ mod = mkPackageModule mod_nm -- Not necessarily right yet
+ lookup_sub parent occ = newGlobalBinder mod occ (Just parent) noSrcLoc
+ -- Hack alert! Notice the newGlobalBinder. It ensures that the subordinate
+ -- names record their parent; and that in turn ensures that the GlobalRdrEnv
+ -- has the correct parent for all the names in its range.
+ -- For imported things, we only suck in the binding site later, if ever.
+ -- Reason for all this:
+ -- Suppose module M exports type A.T, and constructor A.MkT
+ -- Then, we know that A.MkT is a subordinate name of A.T,
+ -- even though we aren't at the binding site of A.T
+ -- And it's important, because we may simply re-export A.T
+ -- without ever sucking in the declaration itself.
+
+warnRedundantSourceImport mod_name
+ = ptext SLIT("Unnecessary {- SOURCE -} in the import of module")
+ <+> quotes (ppr mod_name)