const keyword

In CTE const used to declare, obviously, a constant which will be evaluated at compile-time and which usages will be inlined.

I wanna note that const is a synonym for compile-time evaluable expression, so further I'll use it in this context.

const must be immediately assigned when declared. Syntax.

'const' IDENT '=' expr

After '=' goes an expression which MUST also be CTE, but not exactly another const.

The difference between let and const is that const is an item, whereas let is a statement. As being an item const can be placed mostly on any level, including top-level.

const a = 10

trait MyTrait {
    const traitConst = 1010
}

func main() {
    const b = 123
}