src/test/compile-fail/lifetime-inference-give-expl-lifetime-param-2.rs

   1 // Copyright 2014 The Rust Project Developers. See the COPYRIGHT
   2 // file at the top-level directory of this distribution and at
   3 // http://rust-lang.org/COPYRIGHT.
   4 //
   5 // Licensed under the Apache License, Version 2.0 <LICENSE-APACHE or
   6 // http://www.apache.org/licenses/LICENSE-2.0> or the MIT license
   7 // <LICENSE-MIT or http://opensource.org/licenses/MIT>, at your
   8 // option. This file may not be copied, modified, or distributed
   9 // except according to those terms.
  10
  11 // ignore-tidy-linelength
  12
  13 use std::ops::Range;
  14
  15 trait Itble<'r, T, I: Iterator<Item=T>> { fn iter(&'r self) -> I; }
  16
  17 impl<'r> Itble<'r, usize, Range<usize>> for (usize, usize) {
  18     fn iter(&'r self) -> Range<usize> {
  19         let &(min, max) = self;
  20         min..max
  21     }
  22 }
  23
  24 fn check<'r, I: Iterator<Item=usize>, T: Itble<'r, usize, I>>(cont: &T) -> bool {
  25 //~^ HELP: consider using an explicit lifetime parameter as shown: fn check<'r, I: Iterator<Item = usize>, T: Itble<'r, usize, I>>(cont: &'r T)
  26     let cont_iter = cont.iter(); //~ ERROR: cannot infer
  27     let result = cont_iter.fold(Some(0), |state, val| {
  28         state.map_or(None, |mask| {
  29             let bit = 1 << val;
  30             if mask & bit == 0 {Some(mask|bit)} else {None}
  31         })
  32     });
  33     result.is_some()
  34 }
  35
  36 fn main() {}