src/test/ui/single-use-lifetime/one-use-in-trait-method-argument.rs

   1 // Copyright 2016 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 // Test that we DO warn for a lifetime on an impl used only in `&self`
  12 // in a trait method.
  13
  14 #![deny(single_use_lifetimes)]
  15 #![allow(dead_code)]
  16 #![allow(unused_variables)]
  17
  18 struct Foo<'f> {
  19     data: &'f u32
  20 }
  21
  22 impl<'f> Iterator for Foo<'f> {
  23     type Item = &'f u32;
  24
  25     fn next<'g>(&'g mut self) -> Option<Self::Item> { //~ ERROR `'g` only used once
  26         None
  27     }
  28 }
  29
  30 fn main() { }