#15679: Use String rather than [Char] where possible -------------------------------------+------------------------------------- Reporter: simonpj | Owner: (none) Type: bug | Status: new Priority: normal | Milestone: 8.6.1 Component: Compiler | Version: 8.6.1 Keywords: | Operating System: Unknown/Multiple Architecture: | Type of failure: None/Unknown Unknown/Multiple | Test Case: | Blocked By: Blocking: | Related Tickets: Differential Rev(s): | Wiki Page: -------------------------------------+------------------------------------- Try this in GHCi {{{ Prelude> :t "foo" "foo" :: [Char] }}} It would be better to say {{{ "foo" :: String }}} Why don't we? Because of this in `TysWiredIn` {{{ stringTy :: Type stringTy = mkListTy charTy -- convenience only }}} That is, where GHC needs `String` is uses `stringTy` which is just `[Char]`. How to fix? Two ways: 1. Make `String` into a "wired-in type". That's not hard, but it increases the number of wired-in types, which is generally undesirable. 2. Make `String` into a "knonw-key name", and look it up in the type environment on the (few) occasions where we need `stringTy`. That's a little harder -- notably `hsLitType` would become monadic -- but not difficult. -- Ticket URL: http://ghc.haskell.org/trac/ghc/ticket/15679 GHC http://www.haskell.org/ghc/ The Glasgow Haskell Compiler