error[E0308]: mismatched types --> $DIR/hr-subtype.rs:49:26 | LL | gimme::<$t1>(None::<$t2>); | ^^^^^^^^^^^ lifetime mismatch ... LL | / check! { free_x_vs_free_y: (fn(&'x u32), LL | | fn(&'y u32)) } | |__________________________________________- in this macro invocation | = note: expected type `std::option::Option` found type `std::option::Option` note: the lifetime 'x as defined on the function body at 48:22... --> $DIR/hr-subtype.rs:48:22 | LL | fn supertype<'x,'y:'x,'z:'y>() { | ^^ ... LL | / check! { free_x_vs_free_y: (fn(&'x u32), LL | | fn(&'y u32)) } | |__________________________________________- in this macro invocation note: ...does not necessarily outlive the lifetime 'y as defined on the function body at 48:25 --> $DIR/hr-subtype.rs:48:25 | LL | fn supertype<'x,'y:'x,'z:'y>() { | ^^ ... LL | / check! { free_x_vs_free_y: (fn(&'x u32), LL | | fn(&'y u32)) } | |__________________________________________- in this macro invocation error: aborting due to previous error For more information about this error, try `rustc --explain E0308`.