`int a <- b <- 0` or `int a := b := 0` would have worked just as well.
Programmers using equals for assignment is a bit of a misunderstanding of what the mathematical idiom "let x = 5" means. The assignment is signaled by "let", not by "=". In fact, several programming languages use "let" exactly for this purpose too.
In fact, it's not easy to have this kind of bug on your language. C just has it because people wanted to write stuff like `int a = b = 0`.