#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): Another strange result made visible using `-fprint-explicit-foralls`: {{{ $ ghci -fprint-explicit-foralls GHCi, version 7.8.2: http://www.haskell.org/ghc/ :? for help
let a = [1]
:print a a = (_t1::Num t => [t])
:show bindings a :: forall t. Num t => [t] = _ _t1 :: Num t => [t] = _ }}}
It looks like free type variable `t` in the signature of `_t1` causes GHC panic while typechecking it. But I can't figure out whether it is a bug of rtti type reconstruction in `:print` or incorrect behaviour during typechecking. -- Ticket URL: http://ghc.haskell.org/trac/ghc/ticket/9046#comment:4 GHC http://www.haskell.org/ghc/ The Glasgow Haskell Compiler