cargo explain

When rustc finds an error, it returns an error code and advises you to read more about it:

For more information about this error, try rustc --explain E0716.

These explanations are very useful:

But they don't have syntax highlighting. cargo explain does:

Another useful tool is mdcat. Out of the box, the syntax highlighting is not as nice, because it's meant to be a generic markdown reader and the code snippets returned by rustc --explain do not include "```rust":