compile: make Regex::new(r"(?-u:\B)") fail again #1007
Merged
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This regex failed to compile in
regex <1.8
, but the migration to regex-automata tweaked the rules in a subtle way that permitted it to compile despite the fact that the old/status-quo matching engines can't handle it correctly. By that, I mean that they may permit the \B to match between code units. That in turn results in panicking when slicing a &str.In
regex 1.9
, this regex will actually be able to be compiled, but the matching engines will correctly and robustly never report matches that split UTF-8 code units. For now, we just add code that causesregex 1.8
to have the same behavior as previous releases.Fixes #1006