> Note: According to the official RFC the part of an email address before the @-sign could be case-sensitive, but all major email hosts treat them as case-insen

> Note: According to the official RFC the part of an email address before the @-sign could be case-sensitive, but all major email hosts treat them as case-insensitive and so it's not unreasonable for a domain type to take this knowledge into consideration. I don't think that's how types work.