#15520: Invalid warning Defined but not used -------------------------------------+------------------------------------- Reporter: rik | Owner: (none) Type: bug | Status: infoneeded Priority: normal | Milestone: 8.6.1 Component: Compiler | Version: 8.4.3 Resolution: | Keywords: Operating System: Unknown/Multiple | Architecture: | Unknown/Multiple Type of failure: None/Unknown | Test Case: Blocked By: | Blocking: Related Tickets: | Differential Rev(s): Wiki Page: | -------------------------------------+------------------------------------- Comment (by rik): {{{ However, this is correct behavior, since x is not used anywhere (and therefore :+++ is transitively not used) }}} Okay, I see now, I'm confused. `x` is exported so GHC does not know if it is used outside this module, so why this warning? See also https://downloads.haskell.org/~ghc/latest/docs/html/users_guide/using- warnings.html?highlight=unused-top-binds#ghc-flag--Wunused-top-binds {{{ A variable is regarded as “used” if It is exported, or It appears in the right hand side of a binding that binds at least one used variable that is used }}} -- Ticket URL: http://ghc.haskell.org/trac/ghc/ticket/15520#comment:5 GHC http://www.haskell.org/ghc/ The Glasgow Haskell Compiler