re_rebalance_coherence
The tracking issue for this feature is: #55437
The re_rebalance_coherence
feature tweaks the rules regarding which trait
impls are allowed in crates.
The following rule is used:
Given impl<P1..=Pn> Trait<T1..=Tn> for T0
, an impl is valid only if at
least one of the following is true:
Trait
is a local trait- All of
- At least one of the types
T0..=Tn
must be a local type. LetTi
be the first such type. - No uncovered type parameters
P1..=Pn
may appear inT0..Ti
(excludingTi
)
- At least one of the types
See the RFC for details.