error: lifetime parameter `'f` only used once --> $DIR/two-uses-in-inherent-method-argument-and-return.rs:12:6 | LL | impl<'f> Foo<'f> { | ^^ -- ...is used only here | | | this lifetime... | note: the lint level is defined here --> $DIR/two-uses-in-inherent-method-argument-and-return.rs:4:9 | LL | #![deny(single_use_lifetimes)] | ^^^^^^^^^^^^^^^^^^^^ help: elide the single-use lifetime | LL - impl<'f> Foo<'f> { LL + impl Foo<'_> { | error: aborting due to 1 previous error