Language.Haskell.TH.Desugar.Expand

Expands type synonyms and open type families in desugared types, ignoring closed type families. See also the package th-expand-syns for doing this to non-desugared types.

Documentation

expand :: (DsMonad q, Data a) => a -> q a

Expand all type synonyms and open type families in the desugared abstract syntax tree provided. Normally, the first parameter should have a type like DExp or DLetDec.

expandType :: DsMonad q => DType -> q DType

Expands all type synonyms in a desugared type. Also expands open type family applications, as long as the arguments have no free variables. Attempts to expand closed type family applications, but aborts the moment it spots anything strange, like a nested type family application or type variable.

substTy :: DsMonad q => Map Name DType -> DType -> q DType

Capture-avoiding substitution on types