[GHC] #14296: Add `Lift Exp` instance to `Language.Haskell.TH.Syntax`

#14296: Add `Lift Exp` instance to `Language.Haskell.TH.Syntax` -------------------------------------+------------------------------------- Reporter: heisenbug | Owner: (none) Type: feature | Status: new request | Priority: normal | Milestone: Component: Template | Version: 8.2.1 Haskell | Keywords: | Operating System: Unknown/Multiple Architecture: | Type of failure: Poor/confusing Unknown/Multiple | error message Test Case: | Blocked By: Blocking: | Related Tickets: Differential Rev(s): | Wiki Page: -------------------------------------+------------------------------------- Being open-minded, I played around with TH quotations and encountered a strange error message: TyFamWitnesses.hs:106:40-71: error: • No instance for (Lift Exp) arising from a use of ‘lift’ • In the expression: lift eqTypeRep In the expression: {{{ [| eqTypeRep (typeRep @Maybe) |] pending(rn) [] In an equation for ‘fun'’: fun' = [| eqTypeRep (typeRep @Maybe) |] pending(rn) [] | 106 | fun' = [e|eqTypeRep (typeRep @ Maybe)|] | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ }}} Failed, 0 modules loaded. Adding an orphan instance locally helped (of course). {{{#!hs instance Lift Exp where lift = pure }}} It appears to be the right thing to do... Why isn't this in `Language.Haskell.TH.Syntax`? Just forgotten? If so, and somebody gives me a thumbs up, I'll add it tomorrow to HEAD (with a corresponding @since annotation). -- Ticket URL: http://ghc.haskell.org/trac/ghc/ticket/14296 GHC http://www.haskell.org/ghc/ The Glasgow Haskell Compiler