Pre-RFC: typed context injection

language design
6

What's the output of this code?

trait PrintComponents {
	fn print_components();
}

impl<T> PrintComponents for CxRaw<(T,)> {
	fn print_components(&self) {
		print!("1");
	}
}

impl<T, U> PrintComponents for CxRaw<(T, U)> {
	fn print_components(&self) {
		print!("2");
	}
}

let closure = |x, y| {
	// we start out knowing nothing about the relation between x and y's type
	Cx::new((x, y)).print_components();
	[&x, &y]; // x and y now known to have the same type
	Cx::new((x, y)).print_components();
};

closure((), ());