error[E0401]: can't use generic parameters from outer function --> $DIR/issue-3021-c.rs:4:24 | LL | fn siphash() { | - type parameter from outer function LL | LL | trait U { | - help: try using a local generic parameter instead: `` LL | fn g(&self, x: T) -> T; | ^ use of generic parameter from outer function error[E0401]: can't use generic parameters from outer function --> $DIR/issue-3021-c.rs:4:30 | LL | fn siphash() { | - type parameter from outer function LL | LL | trait U { | - help: try using a local generic parameter instead: `` LL | fn g(&self, x: T) -> T; | ^ use of generic parameter from outer function error: aborting due to 2 previous errors For more information about this error, try `rustc --explain E0401`.