@, NoLocalPart @example.com, NoLocalPart abc@, NoDomainPart abc, NoSignAt abc@def@example.com, TooAt .abc@example.com, LocalStartPeriod abc.@example.com, LocalEndPeriod abc@.example.com, DomainStartPeriod abc@example.com., DomainEndPeriod ab..cd@example.com, ConsecutivePeriod abc@example..com, ConsecutivePeriod a@example, NoPeriodDomain ab\c@example.com, WrongCharLocal('\\') "ab""c""def@example.com", WrongCharLocal('"') abc def@example.com, WrongCharLocal(' ') (comment)abc@example.com, WrongCharLocal('(') abc@[255.255.255.255], WrongCharDomain('[') abc@(example.com, WrongCharDomain('(') abc@x.y_y.z, WrongCharDomain('_') abc@-example.com, WrongStartLabel('-') abc@example-.com, WrongEndLabel('-') abc@x.-y.z, WrongStartLabel('-') abc@x.y-.z, WrongEndLabel('-') abc@1example.com, WrongStartLabel('1') abc@x.123, WrongStartLabel('1') abcd€f@example.com, NoAscii(AsciiError { ch: '€' }) abc@exámple.com, NoAscii(AsciiError { ch: 'á' } )