data TcTyVarDetails
= SkolemTv SkolemInfo -- A skolem constant
- | FlatSkol TcType -- The "skolem" obtained by flattening during
- -- constraint simplification
+ | FlatSkol TcType
+ -- The "skolem" obtained by flattening during
+ -- constraint simplification
- -- In comments we will use the notation alpha[flat = ty]
- -- to represent a flattening skolem variable alpha
- -- identified with type ty.
-
+ -- In comments we will use the notation alpha[flat = ty]
+ -- to represent a flattening skolem variable alpha
+ -- identified with type ty.
+
| MetaTv MetaInfo (IORef MetaDetails)
data MetaDetails
- = Flexi -- Flexi type variables unify to become Indirects
+ = Flexi -- Flexi type variables unify to become Indirects
| Indirect TcType
data MetaInfo
pprTcTyVarDetails :: TcTyVarDetails -> SDoc
-- For debugging
pprTcTyVarDetails (SkolemTv _) = ptext (sLit "sk")
-pprTcTyVarDetails (FlatSkol _) = ptext (sLit "fsk")
+pprTcTyVarDetails (FlatSkol {}) = ptext (sLit "fsk")
pprTcTyVarDetails (MetaTv TauTv _) = ptext (sLit "tau")
pprTcTyVarDetails (MetaTv (SigTv _) _) = ptext (sLit "sig")
quotes (ppr tv) <+> ppr_details (tcTyVarDetails tv)
where
ppr_details (SkolemTv info) = ppr_skol info
- ppr_details (FlatSkol _) = ptext (sLit "is a flattening type variable")
+ ppr_details (FlatSkol {}) = ptext (sLit "is a flattening type variable")
ppr_details (MetaTv TauTv _) = ptext (sLit "is a meta type variable")
ppr_details (MetaTv (SigTv n) _) = ptext (sLit "is bound by the type signature for") <+> quotes (ppr n)