#11051: GHCi with +t option set shows type representations -------------------------------------+------------------------------------- Reporter: bgamari | Owner: bgamari Type: bug | Status: new Priority: normal | Milestone: Component: Compiler | Version: 7.11 Resolution: | Keywords: Operating System: Unknown/Multiple | Architecture: Type of failure: Incorrect result | Unknown/Multiple at runtime | Test Case: Blocked By: | Blocking: Related Tickets: | Differential Rev(s): Wiki Page: | -------------------------------------+------------------------------------- Comment (by bgamari): My guess is that we'd want to do something like this to ensure that `System` names never make it to the user. {{{#!patch diff --git a/compiler/main/InteractiveEval.hs b/compiler/main/InteractiveEval.hs index 013be3c..d3020d7 100644 --- a/compiler/main/InteractiveEval.hs +++ b/compiler/main/InteractiveEval.hs @@ -235,8 +235,9 @@ runStmtWithLocation source linenumber expr step = do runDecls :: GhcMonad m => String -> m [Name] runDecls = runDeclsWithLocation "<interactive>" 1 -runDeclsWithLocation - :: GhcMonad m => String -> Int -> String -> m [Name] +-- | Run some declarations and return any user-visible names that were brought +-- into scope. +runDeclsWithLocation :: GhcMonad m => String -> Int -> String -> m [Name] runDeclsWithLocation source linenumber expr = do hsc_env <- getSession @@ -246,7 +247,13 @@ runDeclsWithLocation source linenumber expr = hsc_env <- getSession hsc_env' <- liftIO $ rttiEnvironment hsc_env modifySession (\_ -> hsc_env') - return (map getName tyThings) + + -- Trac #11051: We filter out system names since the user is not interested + -- in them. These include, + -- * Data family tycons from, e.g., derived Generic instances + -- * Type representation (Typeable) definitions (e.g. $trMyModule) + -- * others + return $ filter (not . isSystemName) $ map getName tyThings }}} With this we've reduced the problem to ensuring that the generated Typeable identifiers get marked as `System` names. Currently they are conjured by up `IfaceEnv.newGlobalBinder` which only knows how to produce `External` names. -- Ticket URL: http://ghc.haskell.org/trac/ghc/ticket/11051#comment:5 GHC http://www.haskell.org/ghc/ The Glasgow Haskell Compiler