The path_statements lint detects path statements with no effect.
The unused_allocation lint detects unnecessary allocations that can
be eliminated.
The unused_braces lint detects unnecessary braces around an
expression.
The unused_import_braces lint catches unnecessary braces around an
imported item.
The unused_must_use lint detects unused result of a type flagged as
#[must_use].
The unused_parens lint detects if, match, while and return
with parentheses; they do not need them.
The unused_results lint checks for the unused result of an
expression in a statement.