pub trait FuncMarker<P>: Sealed<P> { }Expand description
Marker trait for marker types specifying what to map over
This is only implemented by the marker types TypeParam<N> and is used to
restrict the choice of types for the P type parameter of
FuncMap<A, B, P> and TryFuncMap<A, B, P>.
Note that FuncMarker<P> is itself generic over P and for all
implementations, the type parameter P is the implementing type itself.
This way, from Q: FuncMarker<P> it can be inferred that Q == P, which is
used in the FuncMap::func_map_over and TryFuncMap::try_func_map_over
methods.
This trait is sealed and cannot be implemented outside of funcmap.