rust-lang/rust — pull request #19413 by P1start (2014-11-30 04:50:47+00:00)
Title: Allow trailing commas in array patterns and attributes

The only other place I know of that doesn’t allow trailing commas is closure types, and those are a bit tricky to fix (I suspect it might be impossible without infinite lookahead) so I didn’t implement that in this patch. There are other issues surrounding closure type parsing anyway, in particular #19410.