| // Copyright 2015 The Rust Project Developers. See the COPYRIGHT |
| // file at the top-level directory of this distribution and at |
| // http://rust-lang.org/COPYRIGHT. |
| // |
| // Licensed under the Apache License, Version 2.0 <LICENSE-APACHE or |
| // http://www.apache.org/licenses/LICENSE-2.0> or the MIT license |
| // <LICENSE-MIT or http://opensource.org/licenses/MIT>, at your |
| // option. This file may not be copied, modified, or distributed |
| // except according to those terms. |
| |
| pub enum Expr<'var, VAR> { |
| Let(Box<Expr<'var, VAR>>, |
| Box<for<'v> Fn(Expr<'v, VAR>) -> Expr<'v, VAR> + 'var>) |
| } |
| |
| pub fn add<'var, VAR> |
| (a: Expr<'var, VAR>, b: Expr<'var, VAR>) -> Expr<'var, VAR> { |
| loop {} |
| } |
| |
| pub fn let_<'var, VAR, F: for<'v> Fn(Expr<'v, VAR>) -> Expr<'v, VAR>> |
| (a: Expr<'var, VAR>, b: F) -> Expr<'var, VAR> { |
| loop {} |
| } |
| |
| fn main() { |
| let ex = |x| { //~ ERROR type annotations needed |
| let_(add(x,x), |y| { |
| let_(add(x, x), |x|x)})}; |
| } |