remove T{} syntax in favor of type coercion

[andrewrk]

The following are semantically equivalent:

const a = T{};
const a: T = .{};
const a = @as(T, .{});

I propose to remove the first possibility, and rely on the other two.

The problem with this proposal as I can see it is inferred-size array literals:

const a = [_]u8{1, 2, 3};

There's no other way to write this. And if that works, then why wouldn't this work?

const a = [3]u8{1, 2, 3};

But now we're back to the proposal:

const a = [3]u8{1, 2, 3};
const a: [3]u8 = .{1, 2, 3};
const a = @as([3]u8, .{1, 2, 3});

[JesseRMeyer]

What problem does this solve?

const a = T{}; is the simplest expression of the three, in terms of concepts necessary to define the assignment semantics. .{} introduces anonymous structs, and @as() introduces a compiler 'function'.

I'm not convinced reducing the number of ways to define an assignment is worth removing the simplest solution to the problem, if I understand this correctly.

[jakwings]

How about this?

const a = T.{};

const a = [_]u8.{};
const a = [_]u8.{1, 2, 3};

[emekoi]

@iology see #760, specifically this part.

[mogud]

// I prefer this
const a: [_]u8 = .{1, 2, 3};

[foobles]

I would definitely be in favor of this, just as long as the . in .{} is removed at the same time, which seems to be in the works.