Match return option followed by return in case of None

What it does

This lint can flag match that return option and that are directly followed by a return in case of None with/without error mapping. They could be factorized to not return an option and return directly the error he is mapped to.

Lint Name

match_return_too_complex

Category

style, complexity

Advantage

• Simplify the code by removing a combinator call

Drawbacks

No response

Example

let a = match self.block_statuses.get(&cur_h) {
    Some(block) => Some(block.id),
     _ => None,
}.ok_or_else(|| "Error".to_string())?;

Could be written as:

let a = match self.block_statuses.get(&cur_h) {
    Some(block) => block.id,
     _ => return Err("Error".to_string()),
};

Start by locating the implementation and tests for the match_return_too_complex lint, then compare them with the issue's Some/None example. Done means the lint recognizes matches that immediately convert an optional result into an error and supports the direct-return form without flagging unrelated matches.