Discussed here and here.

Using the derive crate assumes a direct dependency on parity-scale-codec from the user's crate. Brainstorming ideas:

• as Basti suggests do a reexport of the required types (see comment)
• better error message if the crate is not present
• add a feature "compact" or so to enable that functionality for which the codec types are required.
• make the macro determine whether any compact fields are present and only import the lib.

This also feeds into the larger discussion about how these two libraries coexist, and to what extent they should be coupled.

/cc @Robbepop @dvdplm @ordian