Module frunk::indices

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Types used for indexing into HLists and coproducts.

frunk frequently uses phantom index types as a technique to avoid overlapping impls for some traits.

Currently, Index type parameters in traits are not ever really intended to be selected by the user, and are instead simply solved for by type inference wherever the compiler can see that there is a unique solution. Therefore, you don’t really have much of a reason to use the things in this module.

…yet. ;)



  • Index for the case where we don’t need to do any transmogrifying at all because the source type is the same as the target type.