#15316: Regarding coherence and implication loops in presence of QuantifiedConstraints -------------------------------------+------------------------------------- Reporter: mniip | Owner: (none) Type: bug | Status: merge Priority: high | Milestone: 8.6.1 Component: Compiler (Type | Version: 8.5 checker) | Keywords: Resolution: | QuantifiedConstraints Operating System: Unknown/Multiple | Architecture: | Unknown/Multiple Type of failure: GHC accepts | Test Case: quantified- invalid program | constraints/T15316 Blocked By: | Blocking: Related Tickets: | Differential Rev(s): Wiki Page: | -------------------------------------+------------------------------------- Comment (by simonpj):
Doesn't UndecidableInstances imply the typechecking might not terminate, as opposed to a finite typechecking process resulting in a program nonterminating due to poor case of context elaboration?
Usually yes, but in the cases above it can mean the latter too. -- Ticket URL: http://ghc.haskell.org/trac/ghc/ticket/15316#comment:11 GHC http://www.haskell.org/ghc/ The Glasgow Haskell Compiler