#9046: Panic in GHCi when using :print -------------------------------------+------------------------------------ Reporter: quchen | Owner: Type: bug | Status: new Priority: normal | Milestone: 7.8.4 Component: GHCi | Version: 7.8.2 Resolution: | Keywords: Operating System: Unknown/Multiple | Architecture: Unknown/Multiple Type of failure: GHCi crash | Difficulty: Unknown Test Case: | Blocked By: Blocking: | Related Tickets: -------------------------------------+------------------------------------ Comment (by bravit): No problem for unbounded polymorphic type variable: {{{ $ ghci -fprint-explicit-foralls GHCi, version 7.8.2: http://www.haskell.org/ghc/ :? for help
:t length length :: forall a. [a] -> Int
:print length length = (_t1::[a] -> Int)
:t _t1 _t1 :: [a] -> Int }}} But: {{{ :t read read :: forall a. Read a => String -> a
:print read read = (_t2::Read a1 => String -> a1)
:t _t2 ghc: panic! (the 'impossible' happened) (GHC version 7.8.2 for x86_64-unknown-linux): tcTyVarDetails a1{tv asM} [tv] }}}
-- Ticket URL: http://ghc.haskell.org/trac/ghc/ticket/9046#comment:5 GHC http://www.haskell.org/ghc/ The Glasgow Haskell Compiler