mozilla/rust — pull request #8982 by blake2-ppc (2013-09-04 22:51:28+00:00)
Title: std::str: Deny surrogates in is_utf8

Reject codepoints \uD800 to \uDFFF which are the surrogates
(reserved/unused codepoints that are invalid to encode into UTF-8)

The surrogates is the only hole of invalid codepoints in the range from
\u0 to \u10FFFF.