`clippy::string_slice`

Use get on the string range and handle the absent slice; byte indexing panics inside a UTF-8 character.

What it reads

Clippy, with the compiler behind it. The only pass that compiles.

Lowest tier: real, and rarely urgent.

The tier bounds how severe a rule may be; its category bounds the tier.

Turn it off, or make it blocking, without touching the code it flags:

rust-doctor --rule clippy::string_slice=off .
rust-doctor --rule clippy::string_slice=error .