#14084: Strange behavior of GHC by writing the types in GHCi -------------------------------------+------------------------------------- Reporter: vanto | Owner: (none) Type: bug | Status: closed Priority: normal | Milestone: Component: GHCi | Version: 8.0.2 Resolution: invalid | Keywords: Operating System: Unknown/Multiple | Architecture: Type of failure: Incorrect result | Unknown/Multiple at runtime | Test Case: Blocked By: | Blocking: Related Tickets: | Differential Rev(s): Wiki Page: | -------------------------------------+------------------------------------- Comment (by AntC): @vanto, I think you'll get better explanations if you post these kind of questions on StackOverflow, or the beginners forum. If the people there tell you to report a bug, then come to Trac. (For comparison, I've been using GHC for over 10 years. I've never felt a need to raise a bug.) Briefly: this behaviour is correct. When you go {{{ Prelude> 1:2 }}} You are asking to evaluate the expression. (As well as give its type.) To evaluate the expression, GHC must figure out its type. Its type is indeed not Haskell2010-conformant: it needs `FlexibleContexts`. Contrariwise, when you go {{{ Prelude> :t ... }}} You are not asking to evaluate the expression. You are merely asking for its type. GHCi is being generous (I'd say) in telling you the type irrespective of whether that type is conformant with current settings/extensions. I see no bug. -- Ticket URL: http://ghc.haskell.org/trac/ghc/ticket/14084#comment:2 GHC http://www.haskell.org/ghc/ The Glasgow Haskell Compiler