A type synonym for TyVarBndr. This is the recommended way to refer to TyVarBndrs if you wish to achieve backwards compatibility with older versions of template-haskell, where TyVarBndr lacked a flag type parameter (if it has one).

A TyVarBndr with a BndrVis flag. This is used for TyVarBndrs in type-level declarations (e.g., the binders in data D @k (a :: k)).

Because pre-9.8 GHCs do not support invisible binders in type-level declarations, we simply make BndrVis an alias for () as a compatibility shim for old GHCs. This matches how type-level TyVarBndrs were flagged prior to GHC 9.8.

Because pre-9.8 GHCs do not support invisible binders in type-level declarations, we simply make BndrReq a pattern synonym for () as a compatibility shim for old GHCs. This matches how type-level TyVarBndrs were flagged prior to GHC 9.8.

Because pre-9.8 GHCs do not support invisible binders in type-level declarations, this compatibility shim is defined in a somewhat unusual way:

• As a pattern, BndrInvis will never match on pre-9.8 GHCs. That way, if you write pattern matches like this:

  case flag of
    BndrInvis -> ...
    BndrVis -> ...
  

Then the first branch will never be taken on pre-9.8 GHCs.

• BndrInvis is a unidirectional pattern synonym on pre-9.8 GHCs, so it cannot be used as an expression on these GHC versions. This is done in an effort to avoid pitfalls that could occur if BndrInvis were defined like so:

  pattern BndrInvis = ()
  

If this were the definition, then a user could write code involving BndrInvis that would construct an invisible type-level binder on GHC 9.8 or later, but a visible type-level binder on older GHCs! This would be disastrous, so we prevent the user from doing such a thing.

A class characterizing reasonable default values for various TyVarBndr flag types.

Construct a PlainTV with the given flag.

Construct a KindedTV with the given flag.

Construct a PlainTV with an InferredSpec.

Construct a PlainTV with a SpecifiedSpec.

Construct a KindedTV with an InferredSpec.

Construct a KindedTV with a SpecifiedSpec.

Construct a PlainTV with a BndrReq.

Construct a PlainTV with a BndrInvis.

Construct a KindedTV with a BndrReq.

Construct a KindedTV with a BndrInvis.

Case analysis for a TyVarBndr. If the value is a PlainTV n _, apply the first function to n; if it is KindedTV n _ k, apply the second function to n and k.

Case analysis for a TyVarBndr that includes flags in the continuation arguments. Note that TyVarBndrs did not include flags prior to template-haskell-2.17.0.0, so on older versions of template-haskell, these flags instead become ().

Map over the components of a TyVarBndr.

Map over the Name of a TyVarBndr.

Map over the flag of a TyVarBndr.

Map over the Kind of a TyVarBndr.

Traverse the components of a TyVarBndr.

Traverse the Name of a TyVarBndr.

Traverse the flag of a TyVarBndr.

Traverse the Kind of a TyVarBndr.

Map over the components of a TyVarBndr in a monadic fashion.

This is the same as traverseTV, but with a Monad constraint. This is mainly useful for use with old versions of base where Applicative was not a superclass of Monad.

Map over the Name of a TyVarBndr in a monadic fashion.

This is the same as traverseTVName, but with a Monad constraint. This is mainly useful for use with old versions of base where Applicative was not a superclass of Monad.

Map over the flag of a TyVarBndr in a monadic fashion.

This is the same as traverseTVFlag, but with a Monad constraint. This is mainly useful for use with old versions of base where Applicative was not a superclass of Monad.

Map over the Kind of a TyVarBndr in a monadic fashion.

This is the same as traverseTVKind, but with a Monad constraint. This is mainly useful for use with old versions of base where Applicative was not a superclass of Monad.

Set the flag in a list of TyVarBndrs. This is often useful in contexts where one needs to re-use a list of TyVarBndrs from one flag setting to another flag setting. For example, in order to re-use the TyVarBndrs bound by a DataD in a ForallT, one can do the following:

case x of
  DataD _ _ tvbs _ _ _ ->
    ForallT (changeTVFlags SpecifiedSpec tvbs) ...

Extract the type variable name from a TyVarBndr, ignoring the kind signature if one exists.

Extract the kind from a TyVarBndr. Assumes PlainTV has kind *.

Extract the flag from a TyVarBndr. Note that TyVarBndrs did not include flags prior to template-haskell-2.17.0.0, so on older versions of template-haskell, this functions instead returns ().