#16319: unexpected difference between newtype and data ---------------------------------+---------------------------------------- Reporter: pjljvdlaar | Owner: (none) Type: bug | Status: new Priority: normal | Milestone: Component: Compiler | Version: 8.2.2 Resolution: | Keywords: Operating System: Windows | Architecture: Unknown/Multiple Type of failure: None/Unknown | Test Case: Blocked By: | Blocking: Related Tickets: | Differential Rev(s): Wiki Page: | ---------------------------------+---------------------------------------- Comment (by RyanGlScott): Indeed, `GeneralizedNewtypeDeriving` (and `DerivingVia`) have never taken the "stupid theta" (i.e., `DatatypeContexts`) into account when generating code for whatever reason. Fixing this wouldn't be too difficult (I think you'd just need to change the relevant bits in `TcDeriv`), but is it really worth it? `DatatypeContexts` is a deprecated feature: {{{ λ> :set -XDatatypeContexts <no location info>: warning: -XDatatypeContexts is deprecated: It was widely considered a misfeature, and has been removed from the Haskell language. }}} And I'm not sure if it's worthwhile to continue to maintain it. -- Ticket URL: http://ghc.haskell.org/trac/ghc/ticket/16319#comment:2 GHC http://www.haskell.org/ghc/ The Glasgow Haskell Compiler