let MatchSource::IfLetDesugar { .. } = *source, //test if it is an If Let
let ExprMethodCall(_, _, ref result_types) = op.node, //check is expr.ok() has type Result<T,E>.ok()
let PatKind::TupleStruct(ref x, ref y, _) = body[0].pats[0].node, //get operation
let MatchSource::IfLetDesugar { .. } = *source, //test if it is an If Let
let ExprMethodCall(_, _, ref result_types) = op.node, //check is expr.ok() has type Result<T,E>.ok()
let PatKind::TupleStruct(ref x, ref y, _) = body[0].pats[0].node, //get operation