Using a lambda function inside an if statement does not work

[Feliix42]

When trying to compile the following snippet

ns some_ns;

use sf calculations (generate_value, generate_data, calculate, check_if_to_run);

fn main() -> i32 {
    let x = generate_value();
    let y = generate_data();
    let z = check_if_to_run();

    let f = fn(d) { calculate(d, x) };

    if (z) {
        f(y)
    } else {
        y
    }
}

ohuac (v0.2.0) yields the following error:

ohuac: FatalError {fatalErrorMessage = "Undefined Binding: DFVar Binding \"y_0\"
defined vars: fromList [(Binding \"__2\",Target {operator = FnId 7, index = 1}),
(Binding \"z_0\",Target {operator = FnId 2, index = -1}),
(Binding \"a\",Target {operator = FnId 5, index = -1}),
(Binding \"x_0\",Target {operator = FnId 1, index = -1}),
(Binding \"b\",Target {operator = FnId 10, index = -1}),
(Binding \"x_0_0\",Target {operator = FnId 8, index = 0}),
(Binding \"c\",Target {operator = FnId 6, index = -1}),
(Binding \"d_0\",Target {operator = FnId 4, index = -1}),
(Binding \"y_0_0\",Target {operator = FnId 9, index = 0}),
(Binding \"__1\",Target {operator = FnId 7, index = 0})]"}

When writing y instead of f(y), the algorithm compiles.

I guess this is a bug?

[JustusAdam]

Funky. Would it surprise you to hear, that the lambda is actually not the problem? It seems y gets inlined, but only into the first if branch, not the second one.

This is the code it actually produces

let x_0 = calculations/generate_value ()
in let z_0 = calculations/check_if_to_run ()
   in let b =
          ohua.lang/if z_0
            (λ __1 ->
            let d_0 = calculations/generate_data () in let a = calculations/calculate d_0 x_0 in a)
            (λ __2 -> let c = ohua.lang/id y_0 in c)
      in b

[JustusAdam]

This is because inlining an expression also removes its original binding site. I will have to do some investigating into how that can be changed to actually work correctly. I had a similar issue recently actually so I think this is a bit bigger than just this bug

[JustusAdam]

BTW: if you insert the line let y2 = y and then return y2 from the else branch it also compiles correctly :joy: