error[E0261]: use of undeclared lifetime name `'a` --> $DIR/where-lifetime-resolution.rs:6:38 | LL | fn f() where | - help: consider introducing lifetime `'a` here: `<'a>` LL | for<'a> dyn Trait1<'a>: Trait1<'a>, // OK LL | (dyn for<'a> Trait1<'a>): Trait1<'a>, | ^^ undeclared lifetime error[E0316]: nested quantification of lifetimes --> $DIR/where-lifetime-resolution.rs:8:17 | LL | for<'a> dyn for<'b> Trait2<'a, 'b>: Trait2<'a, 'b>, | ^^^^^^^^^^^^^^^^^^^^^^ error[E0261]: use of undeclared lifetime name `'b` --> $DIR/where-lifetime-resolution.rs:8:52 | LL | fn f() where | - help: consider introducing lifetime `'b` here: `<'b>` ... LL | for<'a> dyn for<'b> Trait2<'a, 'b>: Trait2<'a, 'b>, | ^^ undeclared lifetime error: aborting due to 3 previous errors For more information about this error, try `rustc --explain E0261`.