#11661: Missing MonadFail instance for Q monad from TemplateHaskell -------------------------------------+------------------------------------- Reporter: PeterTrsko | Owner: Type: bug | Status: new Priority: normal | Milestone: Component: Template Haskell | Version: 8.0.1-rc2 Resolution: | Keywords: Operating System: Unknown/Multiple | Architecture: | Unknown/Multiple Type of failure: None/Unknown | Test Case: Blocked By: | Blocking: Related Tickets: | Differential Rev(s): Wiki Page: | -------------------------------------+------------------------------------- Comment (by goldfire): I use `fail` in the `Q` monad and `recover` (in singletons). They are useful. I think adding a `MonadFail` superclass is the right way to go. User- defined instances of `Quasi` are rare. And TH generally undergoes quite a bit of churn between releases, so we certainly don't need to worry about the 3-release stability policy. -- Ticket URL: http://ghc.haskell.org/trac/ghc/ticket/11661#comment:8 GHC http://www.haskell.org/ghc/ The Glasgow Haskell Compiler