Feature request: Setting to pull import suggestions/autoimports from core:: not std::

[thomcc]

Sorry in advance if I just failed to find the way to do this.

I would like to be able to configure r-a to prefer core:: for autoimports (err, the import suggestion list, I guess) whenever available, rather than std::. It already does this when it knows #![no_std] is enabled, but often this is conditional on some feature which happens to be on under the current r-a configuration, but isn't guaranteed to be on in that module, etc.

I would honestly even be fine if this option forced r-a to only ever use core:: for this and ignore std::, since I usually have to put imports from std:: in some scope or behind a #[cfg] anyway.

[bjorn3]

I think it makes sense to default to core:: in case of a conditional #![no_std] too and only fallback to std:: if no core:: path exists in that case.

[CryZe]

Would it maybe make sense to just always prefer core over std? That would certainly help people identify subsets of their crates that would work nicely on no_std. And it never really hurts (all that much). Maybe there could be a setting to turn it off.

[jonas-schievink]

I think it makes sense to default to core:: in case of a conditional #![no_std] too and only fallback to std:: if no core:: path exists in that case.

This is now implemented in #12041