getJsIncompatibleType = signature => {
	for (const param of signature.params) {
		if (!JS_COMPAT_TYPES.has(param.valtype)) {
			return `${param.valtype} as parameter`;
		}
	}
	for (const type of signature.results) {
		if (!JS_COMPAT_TYPES.has(type)) return `${type} as result`;
	}
	return null;
}
@param {t.Signature} signature the func signature
@returns {null | string} the type incompatible with js types