Array of bytes has infinite type size about vyper HOT 7 CLOSED

I think the problem with my example is only in function arguments... hmm

from vyper.

Viper assumes maps all have infinite type size; you're right that it's incorrect in that particular case. IMO it's not worth it to have some kind of special-case support for two-item maps.

from vyper.

I agree with you on that, it was a spurious example.

More for my understanding, what is the reasoning behind this decision? A viper contract can store it's own data in maps, which could reach infinite size in theory, but function arguments (or return values) are not allowed to be of variable size. Is this to ensure that gas estimates can be computed, or something more fundamental to the EVM?

I'm still very much learning, excuse my ignorance!

from vyper.

The reason why infinite sized types in general are not allowed as function arguments is indeed gas estimation. The reason why maps specifically are not allowed is that there is no standard for how an entire map can be passed around as a data structure in the ABI, and the code complexity of implementing such a format, as well as the mechanisms for converting between this format and storage maps, is hard.

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@vbuterin as a suggestion, can we change that error message to "Maps are not supported for function arguments or outputs"? A much more descriptive error than "has infinite size"

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@fubuloubu that's great idea.

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Thanks @yograterol. I'll close this one

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