#15753: Inconsistent pattern-match warnings when using guards versus case expressions -------------------------------------+------------------------------------- Reporter: RyanGlScott | Owner: (none) Type: bug | Status: new Priority: normal | Milestone: 8.10.1 Component: Compiler | Version: 8.6.1 Resolution: | Keywords: | PatternMatchWarnings Operating System: Unknown/Multiple | Architecture: Type of failure: Incorrect | Unknown/Multiple error/warning at compile-time | Test Case: Blocked By: | Blocking: Related Tickets: #15884, #16129 | Differential Rev(s): Wiki Page: | -------------------------------------+------------------------------------- Comment (by sjakobi): Another (tiny) reduction: {{{#!hs {-# LANGUAGE PatternSynonyms #-} module Bug where {-# COMPLETE Id #-} pattern Id :: () pattern Id = () bug :: () bug | Id <- id () = () }}} {{{ Bug.hs:9:1: warning: [-Wincomplete-patterns] Pattern match(es) are non-exhaustive In an equation for ‘bug’: Guards do not cover entire pattern space | 9 | bug | Id <- id () = () | ^^^^^^^^^^^^^^^^^^^^^^ }}} -- Ticket URL: http://ghc.haskell.org/trac/ghc/ticket/15753#comment:8 GHC http://www.haskell.org/ghc/ The Glasgow Haskell Compiler