error[E0401]: can't use type parameters from outer function --> $DIR/nested-ty-params.rs:3:16 | LL | fn hd(v: Vec ) -> U { | - type variable from outer function LL | fn hd1(w: [U]) -> U { return w[0]; } | --- ^ use of type variable from outer function | | | help: try using a local type parameter instead: `hd1` error[E0401]: can't use type parameters from outer function --> $DIR/nested-ty-params.rs:3:23 | LL | fn hd(v: Vec ) -> U { | - type variable from outer function LL | fn hd1(w: [U]) -> U { return w[0]; } | --- ^ use of type variable from outer function | | | help: try using a local type parameter instead: `hd1` error: aborting due to 2 previous errors For more information about this error, try `rustc --explain E0401`.