#15720: Assign to literals is allowed in ghci -------------------------------------+------------------------------------- Reporter: sighingnow | Owner: (none) Type: bug | Status: new Priority: normal | Milestone: Component: GHCi | Version: 8.6.1 Resolution: | Keywords: Operating System: Unknown/Multiple | Architecture: Type of failure: GHC accepts | Unknown/Multiple invalid program | Test Case: Blocked By: | Blocking: Related Tickets: | Differential Rev(s): Wiki Page: | -------------------------------------+------------------------------------- Comment (by goldfire): This should perhaps be an on-by-default warning, but it's valid Haskell code. `1 = 2` is a lazy pattern match. Because it's lazy but binds no variables, we never see an error reported. This is maybe silly, but it doesn't quite seem worth putting another rule in Haskell to avoid this possibility. That said, a pattern-match that binds no variables is warned by `-Wunused- pattern-binds`; maybe this should really be its own warning. -- Ticket URL: http://ghc.haskell.org/trac/ghc/ticket/15720#comment:1 GHC http://www.haskell.org/ghc/ The Glasgow Haskell Compiler