Don't require parentheses when accessing nested tuple

[nstoddard]

If you have a nested tuple like this:

let a = ((1u8, 2u8), (3u8, 4u8));

You can't access it like this:

println!("{}", a.1.1);

Instead, you have to do this:

println!("{}", (a.1).1);

I can't think of any good reason why the former shouldn't be allowed. Maybe rustc is parsing it as the number 1.1? It seems like it shouldn't be hard to fix, since the compiler is already able to suggest adding the parentheses.

[sinistersnare]

relevant part of RFC

[ftxqxd]

The RFC originally allowed indexing nested tuples without parentheses, but the team decided that they didn’t want to contort the grammar to support that. FWIW, I recently discovered that parentheses aren’t actually required: you can use whitespace instead; e.g., foo.1 .1. It’s not much of an improvement, though.

[nstoddard]

Okay, feel free to close this if the team thinks it's not worth implementing.

[sffc]

Not high-priority, but it would still be nice to fix this syntax and avoid the search on how to work around it.

[petrochenkov]

@sffc
This was actually implemented recently - #71322.