E056: You passed a function an argument of the wrong type

Every Turf function has a fixed shape – each parameter has its own declared type, and every call has to match that shape exactly. Turf checks this at compile time, before your program ever runs, so a mismatch like this can’t sneak through.

Here’s a function with a clear shape:

fn greet(name: string, times: int): void {    mut i: int = 0;    while i < times {        io::printline(name);        i = i + 1;    }}greet("Ada", 3);   // name gets a string, times gets an int -- matches

If you swap the arguments, or pass the wrong kind of value:

greet(3, "Ada");

…Turf tells you exactly which parameter (by name, and by which argument position) got the wrong type, and what type it actually expects versus what you gave it.

The most common causes are simply passing arguments in the wrong order, or passing a value you assumed was one type when it’s actually another. Since Turf doesn’t automatically convert between types for you (a number won’t silently become text, for example), double-check the function’s declaration and match your call up to it argument by argument.

Run turf --explain E056 in a terminal to read this again.