Go to Rust
The same routine, written by hand in Go and in Rust. It is here so you can see what changes and what does not before anyone quotes you anything.
Before · Go
func Interest(balance, rate decimal.Decimal) decimal.Decimal {
return balance.Mul(rate).Round(2)
}What it becomes · Rust
fn interest(balance: Decimal, rate: Decimal) -> Decimal {
(balance * rate).round_dp(2)
}Below is one routine in both languages. On a real system the same move runs across the whole tree at once — our platform reads every language in it in parallel, builds the dependency graph, and an engineer cuts the boundaries. A million lines is the normal size of that job, and it finishes inside thirty days.
What this looks like on your whole system
On your actual codebase the same move answers the questions a pair of files cannot: which files nothing calls any more, which batch job writes the record another one reads at 02:00, and whether the rewritten version still produces the numbers your auditors saw last month. The assessment comes back with all three, in three to five days.