Commit 269210b0 authored by Ian Lynagh's avatar Ian Lynagh

Do the second part of #2806: Disallow unlifted types in ~ patterns

parent 5f044d48
......@@ -367,6 +367,10 @@ tc_pat pstate lpat@(LazyPat pat) pat_ty thing_inside
-- Check no existentials
; unless (null pat_tvs) $ lazyPatErr lpat pat_tvs
-- Check there are no unlifted types under the lazy pattern
; when (any (isUnLiftedType . idType) $ collectPatBinders pat') $
lazyUnliftedPatErr lpat
-- Check that the pattern has a lifted type
; pat_tv <- newBoxyTyVar liftedTypeKind
; boxyUnify pat_ty (mkTyVarTy pat_tv)
......@@ -1039,6 +1043,12 @@ lazyPatErr _ tvs
hang (ptext (sLit "A lazy (~) pattern cannot match existential or GADT data constructors"))
2 (vcat (map pprSkolTvBinding tvs))
lazyUnliftedPatErr :: OutputableBndr name => Pat name -> TcM ()
lazyUnliftedPatErr pat
= failWithTc $
hang (ptext (sLit "A lazy (~) pattern cannot contain unlifted types"))
2 (ppr pat)
nonRigidMatch :: PatCtxt -> DataCon -> SDoc
nonRigidMatch ctxt con
= hang (ptext (sLit "GADT pattern match in non-rigid context for") <+> quotes (ppr con))
......
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