error[E0515]: cannot return value referencing local data `*b` --> $DIR/regions-trait-variance.rs:38:5 | LL | let bb: &B = &*b; | --- `*b` is borrowed here LL | make_a(bb) | ^^^^^^^^^^ returns a value referencing data owned by the current function error: aborting due to previous error For more information about this error, try `rustc --explain E0515`.