E048: You used '.' on something that isn't an actual instance

Turf has one consistent rule: . is only for reaching into a real instance you’re holding – a variable that actually contains a value. Anything else – a module name, or a struct’s bare type name used without an instance – needs :: instead. This error means you used . on one of those “anything else” cases.

The two most common ways to hit this:

io.printline("hi");   // ERROR -- 'io' is a module, not an instancePoint.origin();        // ERROR -- 'Point' is a struct type, not an instance

Both are fixed the same way – just swap . for :::

io::printline("hi");Point::origin();

A quick way to tell which one you need: if you can point at an actual value on the left (something you got back from Point::new(...) or Point::default(), stored in a variable), that value’s fields and methods use .. Everything else – the module itself, or the type name on its own – always uses ::. So p.sum() is right if p is a real Point you’re holding, but Point.origin() is never right, because Point there is just the type’s name, not a value.

Run turf --explain E048 in a terminal to read this again.