This allows us to use:
(1.26)
- impl Trait
- autoderef in pattern matching
- fixed slice patterns
- inclusive ranges
(1.27)
- dyn Trait
- #[must_use] on functions
To prepare for edition change, dyn is added where applicable. Other
edition changes would require bumping the requirement even higher,
and so they are not applied for now.
The use of this type has several drawbacks:
* It does not allow distinguishing between different error
conditions. In fact, we wrongly conflated some of them
before this commit.
* It does not allow propagation via ? and requires manual use
of map_err, which is especially tiresome for downstream code.
* It prevents us from expanding the set of error conditions
even if right now we have only one.
* It prevents us from blanket using Result<T> everywhere
(a nitpick at most).
Instead, use Result<T, Error> everywhere, and differentiate error
conditions where applicable.
Dario Nieuwenhuis
whitequark
jhwgh1968
Dan Robertson
whitequark
Philipp Oppermann
Steffen Butzer