Lint to find std imports that could be imported as core or alloc

[i509VCB]

What it does

If an import is a type exposed in core or alloc, the lint should warn that a the type could be imported using core or alloc instead.

Lint Name

prefer_core_alloc_imports

Category

pedantic

Advantage

• For crates which support no_std environments, this makes finding accidental std import additions easier that could break the crate when compiling for a no_std environment.

Drawbacks

• Crates which reexport core, alloc or std might behave differently.

Example

use std::mem::size_of;
use std::vec::Vec;

Could be written as:

use core::mem::size_of;
use alloc::vec::Vec;

[Serial-ATA]

Duplicate of #7724

[giraffate]

Thanks for suggesting new lint!

I'm closing this because of #8917 (comment).