import Outputable
import SrcLoc ( Located(..) )
import Maybes
-import MonadUtils
import FastString
-- standard
thisRewriteFam : concat args_eqss)
}
- -- data constructor application => flatten subtypes
+ -- datatype constructor application => flatten subtypes
-- NB: Special cased for efficiency - could be handled as type application
go ty@(TyConApp con args)
| not (isOpenSynTyCon con) -- don't match oversaturated family apps
= do { (args', cargs, args_eqss) <- mapAndUnzip3M go args
- ; if null args_eqss
+ ; let args_eqs = concat args_eqss
+ ; if null args_eqs
then -- unchanged, keep the old type with folded synonyms
return (ty, ty, [])
else
return (mkTyConApp con args',
mkTyConApp con cargs,
- concat args_eqss)
+ args_eqs)
}
-- function type => flatten subtypes
| otherwise
= panic "TcTyFuns.flattenType: synonym family in a rank-n type"
- -- we should never see a predicate type
- go (PredTy _)
- = panic "TcTyFuns.flattenType: unexpected PredType"
+ -- predicate type => handle like a datatype constructor application
+ go (PredTy (ClassP cls tys))
+ = do { (tys', ctys, tys_eqss) <- mapAndUnzip3M go tys
+ ; let tys_eqs = concat tys_eqss
+ ; if null tys_eqs
+ then -- unchanged, keep the old type with folded synonyms
+ return (ty, ty, [])
+ else
+ return (PredTy (ClassP cls tys'),
+ PredTy (ClassP cls ctys),
+ tys_eqs)
+ }
+
+ -- implicit parameter => flatten subtype
+ go ty@(PredTy (IParam ipn ity))
+ = do { (ity', co, eqs) <- go ity
+ ; if null eqs
+ then return (ty, ty, [])
+ else return (PredTy (IParam ipn ity'),
+ PredTy (IParam ipn co),
+ eqs)
+ }
+
+ -- we should never see a equality
+ go (PredTy (EqPred _ _))
+ = panic "TcTyFuns.flattenType: malformed type"
go _ = panic "TcTyFuns: suppress bogus warning"
eqInstMisMatch :: Inst -> TcM a
eqInstMisMatch inst
= ASSERT( isEqInst inst )
- setErrCtxt ctxt $ failWithMisMatch ty_act ty_exp
+ setInstCtxt (instLoc inst) $ failWithMisMatch ty_act ty_exp
where
(ty_act, ty_exp) = eqInstTys inst
- InstLoc _ _ ctxt = instLoc inst
-----------------------
failWithMisMatch :: TcType -> TcType -> TcM a