1 pub enum Expr<'var, VAR> {
2 Let(Box<Expr<'var, VAR>>,
3 Box<dyn for<'v> Fn(Expr<'v, VAR>) -> Expr<'v, VAR> + 'var>)
4 }
5
add<'var, VAR> (a: Expr<'var, VAR>, b: Expr<'var, VAR>) -> Expr<'var, VAR>6 pub fn add<'var, VAR>
7 (a: Expr<'var, VAR>, b: Expr<'var, VAR>) -> Expr<'var, VAR> {
8 loop {}
9 }
10
let_<'var, VAR, F: for<'v> Fn(Expr<'v, VAR>) -> Expr<'v, VAR>> (a: Expr<'var, VAR>, b: F) -> Expr<'var, VAR>11 pub fn let_<'var, VAR, F: for<'v> Fn(Expr<'v, VAR>) -> Expr<'v, VAR>>
12 (a: Expr<'var, VAR>, b: F) -> Expr<'var, VAR> {
13 loop {}
14 }
15
main()16 fn main() {
17 let ex = |x| { //~ ERROR type annotations needed
18 let_(add(x,x), |y| {
19 let_(add(x, x), |x|x)})};
20 }
21