Function env_subset_dots_check 

pub(super) fn env_subset_dots_check(parsed_impl: &ParsedImpl) -> String

The first line of an env class’s [[ (#2174): it takes no argument past name but exact, which it ignores (field and method names match exactly), and nothing reads its ..., on any receiver. Under env(r_data_accessors) the refusal carries the type’s field_error classes.