Independent of the pros and cons of leading commas (which I do think make good pseudo-bullets), one of your examples in the pre-RFC (first post of this thread) is incorrect. You wrote
let (, a, b, c): (, usize, usize, usize) =
(
, 42
, 1337
, 42
);
// equivalent to:
let (a, b, c): (usize, usize, usize) = (1, 2, 3);
I believe most readers would think it equivalent to
let (a, b, c): (usize, usize, usize) = (42, 1337, 42);