Issue with deposit_creating in Currency trait

[Dinonard]

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Description of bug

Hello!

I raised an issue recently in polkadot repo regarding XCM's CurrencyAdapter, however I was told this is more of a issue with the Currency trait.

Basically, the issue is with deposit_creating function which returns PositiveImbalance and is documented as infallible.

/// Adds up to `value` to the free balance of `who`. If `who` doesn't exist, it is created.
///
/// Infallible.
fn deposit_creating(who: &AccountId, value: Self::Balance) -> Self::PositiveImbalance;

However, in case when the deposited value doesn't satisfy the existential requirement, the operation will soft fail, returning Zero equivalent of PositiveImbalance. The ExistentialDeposit error information is lost/hidden which seems wrong (code is here).

Should this be changed to return a Result instead?

Steps to reproduce

No response