E028: You tried to overload an operator for two types Turf already handles

Operator overloading lets you teach Turf what +, -, *, and friends should do for your OWN struct types – like adding two Points together. But Turf already knows how to add two ints, compare two bools, and so on, so it won’t let you redeclare an operator where BOTH sides are builtin types (int, double, bool, char, string, int32). If that were allowed, 1 + 2 would become ambiguous – which version runs, the language’s or yours?

Here’s a valid overload, where at least one side is your own struct:

struct Point {    x: int,    y: int}operator +(a: Point, b: Point): Point {    mut r: Point = Point::default();    r.x = a.x + b.x;    r.y = a.y + b.y;    return r;}

And here’s what triggers this error – both sides are builtin types:

operator +(a: int, b: int): int {    return a;}

To fix it, do one of two things:

• If you meant to add behavior for your own struct, change one of the parameter types from a builtin to your struct’s name – operator +(a: Point, b: int): Point works fine, since one side is now a struct.
• If you were just trying to use + on two plain numbers, you don’t need an overload at all – delete it and use a + b directly, it already does what you want.

This one’s really just Turf protecting you from accidentally breaking how ordinary math works everywhere else in your program.

Run turf --explain E028 in a terminal to read this again.