#11298: Implicit call stack empty in instance declarations -------------------------------------+------------------------------------- Reporter: pikajude | Owner: Type: bug | Status: new Priority: normal | Milestone: 8.0.1 Component: Compiler | Version: 7.11 Resolution: | 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 gridaphobe): I updated the user guide as part of the rewrite, the current version is hosted [http://downloads.haskell.org/~ghc/master/users- guide//glasgow_exts.html#implicit-callstacks here]. It does mention that a bare `?loc :: CallStack` will be resolved to the empty stack ("GHC will never report an unbound implicit CallStack, and will instead default such occurrences to the empty CallStack.") It also describes `getCallStack` for extracting the list of call-sites, and `freezeCallStack` for preventing the addition of further call-sites. There are a couple other API functions (`push` and `pop`) that are only mentioned in the haddocks, but I think that's ok as they're pretty self- explanatory. Ack, I just noticed that the formatting is a bit screwy towards the end of the section, I'll send a patch to clean it up. If you have any comments/suggestions on the content itself I'd be happy to incorporate them. -- Ticket URL: http://ghc.haskell.org/trac/ghc/ticket/11298#comment:7 GHC http://www.haskell.org/ghc/ The Glasgow Haskell Compiler