Function is_reserved_condition_field 

pub const fn is_reserved_condition_field(name: &str) -> bool

true for RESERVED_CONDITION_FIELDS. const so the macros can reject a literal field name at compile time:

mx::rust_error!(data = ("kind", 1), "boom");

Any other name is fine, so the fix for a clash is a rename at the source:

mx::rust_error!(data = ("rule", 1), "boom");