That's not at all the same as saying it was a valid sequence. That's saying decoders were allowed to be lenient with invalid sequences. We're supposed to be comfortable with standards language here. Do we really not understand this distinction?
--Doug Ewell | Thornton, CO, US | ewellic.org -------- Original message --------From: Karl Williamson <pub...@khwilliamson.com> Date: 5/30/17 16:32 (GMT-07:00) To: Doug Ewell <d...@ewellic.org>, Unicode Mailing List <unicode@unicode.org> Subject: Re: Feedback on the proposal to change U+FFFD generation when decoding ill-formed UTF-8 On 05/30/2017 02:30 PM, Doug Ewell via Unicode wrote: > L2/17-168 says: > > "For UTF-8, recommend evaluating maximal subsequences based on the > original structural definition of UTF-8, without ever restricting trail > bytes to less than 80..BF. For example: <C0 AF> is a single maximal > subsequence because C0 was originally a lead byte for two-byte > sequences." > > When was it ever true that C0 was a valid lead byte? And what does that > have to do with (not) restricting trail bytes? Until TUS 3.1, it was legal for UTF-8 parsers to treat the sequence <C0 AF> as U+002F.
