Function type signature

[heliosdrm]

I take this statement:

If a function argument name is written as a tuple (e.g. (x, y) ) instead of just a symbol, then an assignment (x, y) = argument will be inserted for you

as implicitly meaning that foo((a,b)) = print(a, "--", b) is equivalent to:

function foo(argument)
    (a, b) = argument
    print(a, "--", b)
end

And that explains why it redefines foo(a).