0.4.5 breaks API over 0.4.2

[Danvil]

I have a project built against 0.4.2 which suddenly stopped working with compiler errors.

cargo is free to upgrade between "patch" versions, like from 0.4.2 to 0.4.5 as patch versions are not allowed to change the API. Some changes from 0.4.2 to 0.4.5 introduced API changes and should have come with an increase in the minor version number, e.g. "0.5.0".

It is too late for this now, but would be great for the future to only do API changes only via minor version number increase. More info here: https://semver.org

Workaround is to pin the version using "=0.4.2", but this is generally considered bad practice.