detect unnecessary curly braces

What it does

In the following example, there's a single expression inside curly braces. I think clippy should detect that because it is probably not intended. (We have some of these in our codebase due to refactor.)

Lint Name

unecessary_curly_braces

Category

style

Advantage

• Remove lines of code
• Removes indentation
• (Improves readability)

Drawbacks

No response

Example

let a = {
  if cond {
    None
  } else {
    Some(5)
  }
};

Better:

let a = if cond {
  None
} else {
  Some(5)
};

Start by locating Clippy's lint entry points and tests for style lints, then inspect how expression-level curly braces are represented and tested. Use the issue's let a examples as the baseline and verify that the unnecessary outer braces are detected while the braces inside the if expression remain valid. Done means the lint and regression coverage handle this case without false positives.