The current implementation of bitcoin-hashes alias is a significant footgun

[Kixunil]

rust-bitcoin/rust-bitcoin#1450 (comment)

The idiomatic (and expected!) way to activate features is by the crate name. Which is bitcoin_hashes. The secp256k1 crate defines an alias, which is OK but then it itself MUST NOT use that alias. Otherwise the old name won't work and there's no easy way to tell for the users.

Alternatively there could be:

#[cfg(all(feature = "bitcoin_hashes", not(feature = "bitcoin-hashes")))]
compile_error!("Activate feature `bitcoin-hashes` instead of `bitcoin_hashes`");

But I don't see a good reason for forcing people to break the standard way of defining features.

[apoelstra]

I think we should just audit the code for usage of the alias. We should fix this before the release that we're about to push out.

I wouldn't mind removing it ... but if we never gate stuff on it, it should be harmless.

[tcharding]

I made this mess, I'll fix it. You fixed it for me already - thanks. Hilarious, there is a link literally right above this that says you fixed it. My tunnel vision never ceases to amaze me.