Afaik specialisation (in full generality) would cause soundness issues, so it's not even just blocked by the trait solver, it's also blocked by figuring out a 'slimmed down' proposal that fixes those.
And that's not even getting into the problem that it's a fairly controversial feature, since people are worried about terrible, hard to track specialisation trees. (See, inheritance.)
> Afaik specialisation (in full generality) would cause soundness issues, so it's not even just blocked by the trait solver, it's also blocked by figuring out a 'slimmed down' proposal that fixes those.
There is already a proposal for how to prevent unsound specializations [0], but it requires a lot of support from the trait solver, hence why I said it's blocked on it.
And that's not even getting into the problem that it's a fairly controversial feature, since people are worried about terrible, hard to track specialisation trees. (See, inheritance.)