25         None => return i + 1,  in next_utf8()
53         None => return None,  in decode_utf8()
60                 return None;  in decode_utf8()
64                 return None;  in decode_utf8()
69                 _ => None,  in decode_utf8()
74                 return None;  in decode_utf8()
78                 return None;  in decode_utf8()
81                 return None;  in decode_utf8()
89                 _ => None,  in decode_utf8()
94                 return None;  in decode_utf8()
98                 return None;  in decode_utf8()
101                 return None;  in decode_utf8()
104                 return None;  in decode_utf8()
112                 _ => None,  in decode_utf8()
115         _ => None,  in decode_utf8()
123         return None;  in decode_last_utf8()
136         None => None,  in decode_last_utf8()
137         Some((_, n)) if n < src.len() - start => None,  in decode_last_utf8()
223         assert_eq!(decode_utf8(&[0xFF]), None);  in reject_invalid()
225         assert_eq!(decode_utf8(&[0xED, 0xA0, 0x81]), None);  in reject_invalid()
227         assert_eq!(decode_utf8(&[0xD4, 0xC2]), None);  in reject_invalid()
229         assert_eq!(decode_utf8(&[0xC3]), None); // 2 bytes  in reject_invalid()
230         assert_eq!(decode_utf8(&[0xEF, 0xBF]), None); // 3 bytes  in reject_invalid()
231         assert_eq!(decode_utf8(&[0xF4, 0x8F, 0xBF]), None); // 4 bytes  in reject_invalid()
233         assert_eq!(decode_utf8(&[TAG_TWO, TAG_CONT | b'a']), None);  in reject_invalid()
234         assert_eq!(decode_utf8(&[TAG_THREE, TAG_CONT, TAG_CONT | b'a']), None);  in reject_invalid()
237             None  in reject_invalid()
244         assert_eq!(decode_last_utf8(&[0xFF]), None);  in reject_invalid_last()
246         assert_eq!(decode_last_utf8(&[0xED, 0xA0, 0x81]), None);  in reject_invalid_last()
248         assert_eq!(decode_last_utf8(&[0xC3]), None); // 2 bytes  in reject_invalid_last()
249         assert_eq!(decode_last_utf8(&[0xEF, 0xBF]), None); // 3 bytes  in reject_invalid_last()
250         assert_eq!(decode_last_utf8(&[0xF4, 0x8F, 0xBF]), None); // 4 bytes  in reject_invalid_last()
252         assert_eq!(decode_last_utf8(&[TAG_TWO, TAG_CONT | b'a']), None);  in reject_invalid_last()
255             None  in reject_invalid_last()
261             None  in reject_invalid_last()