error: lifetime parameter `'g` only used once
  --> $DIR/one-use-in-trait-method-argument.rs:15:13
   |
LL |     fn next<'g>(&'g mut self) -> Option<Self::Item> {
   |             ^^   -- ...is used only here
   |             |
   |             this lifetime...
   |
note: the lint level is defined here
  --> $DIR/one-use-in-trait-method-argument.rs:4:9
   |
LL | #![deny(single_use_lifetimes)]
   |         ^^^^^^^^^^^^^^^^^^^^
help: elide the single-use lifetime
   |
LL -     fn next<'g>(&'g mut self) -> Option<Self::Item> {
LL +     fn next(&mut self) -> Option<Self::Item> {
   |

error: aborting due to 1 previous error