RFC: Better/Shorter syntax to declare multiple variables

[abbychau]

When we have multiple variable to be declared, we need to write something like this:

let (mut a, mut b, mut c, mut d) = (false, false, false, false);

There are two obvious factorizations:

The first part is to factorize the mut decorator, so to be let mut (a, b, c, d).
Another part is to spread the value tuple, so to be false.

That

let mut (a,b,c,d) = false;

is short while intuitive.

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Last, in the long form

let (mut a, mut b, mut c, mut d) : (bool, bool, bool, bool) = (false, false, false, false);

if the type is required there, then it is able to be shorted to.

let mut (a, b, c, d) : bool = false;

I have thought of making bool and false there a bit more obvious like the JS style spread(not really the spreading meaning here though):
(false..) and (bool..) or using other notations like x!(bool) and [bool], and etc., but I think that keeping the simple form is good enough and because it does not seem to induce much misleadings while reading .

[memoryruins]

For mut shorthand, there is a previous rfc and discussion in rust-lang/rfcs#2401

[jonas-schievink]

Hi! Large additions to the language or standard library need to go through our RFC process. Before an RFC is written, the feature can also be discussed in our internals forum to find other people interested in it.

Closing in favor of an RFC.