Description
What it does
The if-let chains are getting very close to stabilization (they were stabilized but later reverted due to a bug). There are nearly 500 if_chain! usages in this repo alone, so converting them by hand might prove too error-prone. Plus, there are other projects using the same if_chain crate (5 million+ downloads).
I do not know if its possible to create a lint that uses an external crate (any suggestions or links?), but if so, I would think this would be useful to other code as well.
Lint Name
uses_if_chain_crate
Category
complexity
Advantage
keep the code simpler by using non-macro code
Drawbacks
cargo fmt still hasn't been decided (see rfc) on how to handle it, and doesn't seem likely to be decided soon. This is not a blocker, as the code can always be reformatted later. Also, the current macro code is not supported by fmt either, so there is no difference in this regard.
Example
if_chain! {
if let Some(retexpr) = block.expr;
if let Some(stmt) = block.stmts.iter().last();
then {
// ...
}
}Could be written as:
if let Some(retexpr) = block.expr
&& let Some(stmt) = block.stmts.iter().last() {
// ...
}