### What it does

Finds items imported through `std` when available through `core`.

### Why is this bad?

Crates which have `no_std` compatibility may wish to ensure types are imported from core to ensure
disabling `std` does not cause the crate to fail to compile. This lint is also useful for crates
migrating to become `no_std` compatible.

### Example
```
use std::hash::Hasher;
```
Use instead:
```
use core::hash::Hasher;
```