#8778: Typeable TypeNats --------------------------------------------+------------------------------ Reporter: dmcclean | Owner: Type: feature request | Status: new Priority: normal | Milestone: ⊥ Component: Compiler (Type checker) | Version: 7.8.1-rc1 Resolution: | Keywords: Operating System: Unknown/Multiple | Architecture: Type of failure: None/Unknown | Unknown/Multiple Test Case: | Difficulty: Unknown Blocking: | Blocked By: | Related Tickets: 4385 --------------------------------------------+------------------------------ Comment (by simonpj): The issue in #9203 is that a `Typeable` instance should look like {{{ instance Typeable ... where typeRep# = \_ -> rep where rep = ...blah... }}} and NOT like {{{ instance Typeable ... where typeRep# p = ...blah... }}} to ensure that the computation of `rep` is shared among all invocations of `typeRep#`. So Sjoerd is quite right, I think. (I'm a bit confused because I thought we only allowed machine-generated instances of `Typeable`.) BTW if you have a Github account you automatically have a Phabricator account. Simon -- Ticket URL: http://ghc.haskell.org/trac/ghc/ticket/8778#comment:12 GHC http://www.haskell.org/ghc/ The Glasgow Haskell Compiler