#14059: COMPLETE sets don't work at all with data family instances -------------------------------------+------------------------------------- Reporter: RyanGlScott | Owner: (none) Type: bug | Status: new Priority: normal | Milestone: Component: Compiler | Version: 8.2.1 Resolution: | Keywords: | PatternSynonyms, | PatternMatchWarnings 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 RyanGlScott): Evidently, this changed a bit from GHC 8.2 to 8.4. In 8.4, you actually //do// get a warning about `wobble`: {{{ $ /opt/ghc/8.4.2/bin/ghci Bug.hs GHCi, version 8.4.2: http://www.haskell.org/ghc/ :? for help Loaded GHCi configuration from /home/rgscott/.ghci [1 of 1] Compiling Bug ( Bug.hs, interpreted ) Bug.hs:23:1: warning: [-Wincomplete-patterns] Pattern match(es) are non-exhaustive In an equation for ‘wibble’: Patterns not matched: SFalse | 23 | wibble STrue = True | ^^^^^^^^^^^^^^^^^^^ Bug.hs:26:1: warning: [-Wincomplete-patterns] Pattern match(es) are non-exhaustive In an equation for ‘wobble’: Patterns not matched: _ | 26 | wobble STooGoodToBeTrue = True | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ }}} Still, this doesn't seem quite right, as the warning says `Patterns not matched: _` instead of `Patterns not matched: SFalse`, like its counterpart `wibble`. -- Ticket URL: http://ghc.haskell.org/trac/ghc/ticket/14059#comment:5 GHC http://www.haskell.org/ghc/ The Glasgow Haskell Compiler