error: `for<...>` may only modify trait bounds, not lifetime bounds --> $DIR/erroneous-lifetime-bound.rs:1:25 | LL | fn foo() where T: for<'a> 'a {} | ^^^^ error[E0261]: use of undeclared lifetime name `'a` --> $DIR/erroneous-lifetime-bound.rs:1:30 | LL | fn foo() where T: for<'a> 'a {} | ^^ undeclared lifetime | = note: for more information on higher-ranked polymorphism, visit https://doc.rust-lang.org/nomicon/hrtb.html help: consider making the bound lifetime-generic with a new `'a` lifetime | LL | fn foo() where for<'a> T: for<'a> 'a {} | +++++++ help: consider introducing lifetime `'a` here | LL | fn foo<'a, T>() where T: for<'a> 'a {} | +++ error: aborting due to 2 previous errors For more information about this error, try `rustc --explain E0261`.