Variable makeErrorCause is redeclared and causing issues in compiler

Thank you for building this library. This section of code is causing some issues:
```
function makeErrorCause(value, _super) {
if (_super === void 0) { _super = makeErrorCause.BaseError; }
return makeError(value, _super);
}
var makeErrorCause;
```
The function/variable `makeErrorCause` is declared twice, and when SWC tries to compile this module, it throws a compile error that "the name `makeErrorCause` is defined multiple times."

I'm not sure why the 2nd `var` declaration is there, but commenting it out fixes the compile error.