#13839: GHC warnings do not respect the default module header -------------------------------------+------------------------------------- Reporter: Feuerbach | Owner: (none) Type: bug | Status: new Priority: normal | Milestone: Component: Compiler | Version: 8.0.1 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: -------------------------------------+------------------------------------- If I compile this program with `-Wall`, I get no warnings: {{{#!hs type T = Int main :: IO () main = return () }}} If I add a module header: {{{#!hs module Main(main) where type T = Int main :: IO () main = return () }}} I now get a warning: {{{ ghcbug2.hs:3:1: warning: [-Wunused-top-binds] Defined but not used: type constructor or class ‘T’ }}} Yet, according to Haskell2010 (section 5.1):
An abbreviated form of module, consisting only of the module body, is permitted. If this is used, the header is assumed to be ‘module Main(main) where’.
Therefore, the right behaviour should be to print a warning in the first case as well. -- Ticket URL: <http://ghc.haskell.org/trac/ghc/ticket/13839> GHC <http://www.haskell.org/ghc/> The Glasgow Haskell Compiler