internals is not stable and is not going to be. Nothing from internals should appear in the public API of any of the leaf crates.

Fail

core::convert::Into<bitcoin_internals::error::input_string::InputString>>(s: S) -> core::result::Result<T, bitcoin_units::parse::ParseIntError>

Also the parse::int function

pub fn int<T: Integer, S: AsRef<str> + Into<InputString>>(s: S) -> Result<T, ParseIntError> {

As a rule so this doesn't happen again I don't think we should put types into internals - period.

This issue will likely be solved as part of #3732