Lint against `super` (and `self`) imports

[vi013t]

Lint against `super` (and `self`) imports

[J-ZhengLi]

Great idea! but I think maybe it'd be better if it could be implemented in rustfmt? Plus it already has a bunch of options to change the style of imports.

[vi013t]

Fair point, but I personally think it'd be better living here (or both); It'd make it available for projects not using rustfmt, and as you said, rustfmt already has a decent amount of complexity and options for customizing imports; I think it would add a lot of complexity to the configuration to allow all different styles (prefer crate::, prefer super::, prefer self::, allow mixing all of these, don't allow mixing any of these, allow mixing only some two of those three, etc.).

I think as a lint (or a few) it could be quite simple — It could be lints like crate_imports = "allow", self_imports = "allow", and "super_imports = "allow", which would allow many different combinations based on preference from just those few lints. Alternatively, if it's too big of a jump to add in 3 lints to solve one problem, there could simply be a mixed_imports = "warn" lint or something along those lines, that has no preference for crate::, self:: and super:: imports, but at least warns against mixing those different types.

Not that this would be bad for rustfmt, but I think from a configuration standpoint, having it as a lint(s) would be simpler to handle and customize, in addition to giving access to this for projects that don't use rustfmt.