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>)
7 (a: Expr<'var, VAR>, b: Expr<'var, VAR>) -> 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> {
17 let ex = |x| { //~ ERROR type annotations needed
19 let_(add(x, x), |x|x)})};