According to one of our Sanskrit contacts, the following combination is valid in Sanskrit. But it results in a dotted circle in HarfBuzz: रुँः The sequence is: U+0930 U+0941 U+0901 U+0903 RA U CANDRABINDU VISARGA
Here's what Peter Constable has written about it <http://www.unicode.org/mail-arch/unicode-ml/y2009-m05/0026.html>: "As for combinations of candrabindu and visarga, unfortunately there were some early decisions in Uniscribe to impose certain restrictions on Indic sequences, and while I've worked at getting those relaxed in sensible ways this is one restriction that is still there -- a known issue that I plan to have eliminated in a future version."
Will be fixed in tonight's push.commit 5c558877da5db8c734ba072f01e5e4797876619c Author: Behdad Esfahbod <behdad@behdad.org> Date: Wed Oct 16 11:14:15 2013 +0200 [indic] Allow up to two syllable modifiers Bug 70509 - Candrabindu+Visarga doesn't work in Devanagari https://bugs.freedesktop.org/show_bug.cgi?id=70509 We categorize both bindus and visarga as syllable-modifiers. OT spec doesn't actually say what characters go in the syllable modifier category, and allows one. We just allow up to two now. Test case: U+0930,U+0941,U+0901,U+0903 Uniscribe currently doesn't support that and produces a dotted circle.
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