Duplicated types in TypesReturns and TypesArguments

[goastler]

Typechain seems to output duplicate types under the returns and arguments directories. E.g. I have a small contract with 3 methods which generates exactly the same file in TypeArguments and TypeReturns:

types-arguments

export enum LangError {
    couldNotReadInput = 'CouldNotReadInput',
}

export type AccountId = string | number[]

types-returns

export enum LangError {
    couldNotReadInput = 'CouldNotReadInput',
}

export type AccountId = string | number[]

Why are the type-arguments and types-returns separate things and could they be merged? It's very unclear whether I should be using types from the arguments or returns side of things. Further, the duplication makes exporting to other packages annoying due to naming clashes. E.g.

index.ts

export * from './types-arguments'
export * from './types-returns'