But the square brackets used in array access nest, so the parsing is never ambiguous. The reason > needs braces is that without them, if you're parsing and so

But the square brackets used in array access nest, so the parsing is never ambiguous. The reason > needs braces is that without them, if you're parsing and so far you've seen these characters: let y: RectangularArray<i32, X, 2> You don't know if that final > is ending the argument list, or is a greater-than operator, with the rest of an expression coming after it. But if it was square brackets, then a closing square bracket on its own can only ever be the end of the list: let y: RectangularArray[i32, X, 2] Because if it was closing an array access, there would have to have been an opening square bracket: let y: RectangularArray[i32, X, a[1]