Fix region regexes incorrectly matching ^$ at end of line

Because no flags were set for regex matching, the regex engine was
assuming that the subject string past-the-end matched a end-of-line.
As the subject string already ended with a \n character, the regex
engine processing of the "past-the-end" position would match '^$'
as ^ matched past the existing \n and $ matched the assumed
end-of-line.

Fixes #3799

1 files changed, 2 insertions, 1 deletions

diff --git a/src/highlighters.cc b/src/highlighters.cc
index 78099b08..309ade94 100644
--- a/src/highlighters.cc
+++ b/src/highlighters.cc
@@ -1744,7 +1744,8 @@ void insert_matches(const Buffer& buffer, RegexMatchList& matches, const Regex&
     for (auto line = range.begin; line < range.end; ++line)
     {
         const StringView l = buffer[line];
-        for (auto&& m : RegexIterator{l.begin(), l.end(), vm})
+        const auto flags = RegexExecFlags::NotEndOfLine; // buffer line already ends with \n
+        for (auto&& m : RegexIterator{l.begin(), l.end(), vm, flags})
         {
             const bool with_capture = capture and m[1].matched and
                                       m[0].second - m[0].first < std::numeric_limits<uint16_t>::max();