#10982: Warn about unused pattern variables in type families -------------------------------------+------------------------------------- Reporter: jstolarek | Owner: Type: feature | Status: new request | Priority: normal | Milestone: Component: Compiler | Version: 7.11 Keywords: newcomer | Operating System: Unknown/Multiple Architecture: | Type of failure: None/Unknown Unknown/Multiple | Test Case: | Blocked By: Blocking: | Related Tickets: Differential Rev(s): | Wiki Page: -------------------------------------+------------------------------------- Now that we have wildcards in type families (#3699) I want to be warned about unused pattern variables in the same way I am warned about them at the term level. For example this should cause a warning that `b` is not used: {{{#!hs type family F a b type instance F a b = a }}} Prefixing unused variable with an underscore should suppress the warning: {{{#!hs type family F a b type instance F a _b = a }}} -- Ticket URL: http://ghc.haskell.org/trac/ghc/ticket/10982 GHC http://www.haskell.org/ghc/ The Glasgow Haskell Compiler