Forking from #16033, which had two related but different proposals in it. The proposal for this issue, by @robpike:

On a related note, some writing systems - Devanagari is one (see #5167) require combining characters. The current identifier rules forbid combining characters; perhaps that should be relaxed, although that will require a canonicalization rule for combining characters. Unicode does have a definition for identifiers (http://unicode.org/reports/tr31/); perhaps Go should use it. Note that the addition of combining characters, allied with the export proposal above, would make it possible to export Devanagari identifiers.