#12549: Panic on ":t datatypeName" ---------------------------------+-------------------------------------- Reporter: johnleo | Owner: johnleo Type: bug | Status: new Priority: normal | Milestone: Component: Compiler | Version: 8.1 Resolution: | Keywords: Operating System: MacOS X | Architecture: x86_64 (amd64) Type of failure: None/Unknown | Test Case: Blocked By: | Blocking: Related Tickets: | Differential Rev(s): Wiki Page: | ---------------------------------+-------------------------------------- Comment (by simonpj):
everything makes sense except "does not substitute in rho".
Remember: {{{ deeply_instantiate subst ty = deeplyInstantiate (substTy subst ty) }}} So `deeply_instantiate` '''itself''' is responsible for applying `subst` to `ty`, '''not'' the caller of `deeply_instantiate`. So I did miss something: in the `otherwise` case, which currently looks like {{{ | otherwise = return (idHsWrapper, ty) }}} you'll need to use `substTy subst ty`. Also make sure you use `newMetaTyVarsX` so that you pass in the current substitution and get an extended substitution. -- Ticket URL: http://ghc.haskell.org/trac/ghc/ticket/12549#comment:23 GHC http://www.haskell.org/ghc/ The Glasgow Haskell Compiler