**Summary** A common pattern in the code used to be
```rust
if statements.len() != 1 {
return;
}
use_single_entry(statements[0])?;
```
which can be better expressed as
```rust
let [statement] = statements else {
return;
};
use_single_entry(statements)?;
```
Direct indexing can cause panics if you don't manually take care of
checking the length, while matching (such as if-let or let-else) can
never panic.
This isn't a complete refactor, i've just removed some of the obvious
cases. I've specifically looked for `.len() != 1` and fixed those.
**Test Plan** No functional changes