Simon Peyton Jones pushed to branch wip/ani/tc-expand at Glasgow Haskell Compiler / GHC Commits: 893b2ba6 by Simon Peyton Jones at 2026-03-26T23:41:25+00:00 Wibble - - - - - 1 changed file: - compiler/GHC/Tc/Gen/Expr.hs Changes: ===================================== compiler/GHC/Tc/Gen/Expr.hs ===================================== @@ -679,17 +679,21 @@ tcExpr expr@(RecordCon { rcon_con = L loc qcon@(WithUserRdr _ con_name) , rcon_con = L loc con_like , rcon_flds = rbinds' } + ; co <- tcSubTypeMono expr actual_res_ty res_ty + -- Check for missing fields. We do this after type-checking to get -- better types in error messages (cf #18869). For example: -- data T a = MkT { x :: a, y :: a } -- r = MkT { y = True } -- Then we'd like to warn about a missing field `x :: True`, rather than `x :: a0`. -- - -- NB: to do this really properly we should delay reporting until typechecking is complete, - -- via a new `HoleSort`. But that seems too much work. + -- NB: to do this really properly we should delay reporting until typechecking + -- is complete, via a new `HoleSort`. But that seems too much work. + -- + -- However, it's worth doing it after calling `tcSubTypeMono`, + -- which may do some useful unifications ; checkMissingFields con_like rbinds arg_tys - ; co <- tcSubTypeMono expr actual_res_ty res_ty ; return (mkHsWrapCo co expr') } where orig = OccurrenceOf con_name View it on GitLab: https://gitlab.haskell.org/ghc/ghc/-/commit/893b2ba640a22adc06e2c7a04c9ea5cf... -- View it on GitLab: https://gitlab.haskell.org/ghc/ghc/-/commit/893b2ba640a22adc06e2c7a04c9ea5cf... You're receiving this email because of your account on gitlab.haskell.org.