// compile-flags: -Zdrop-tracking #![feature(generators, negative_impls, rustc_attrs)] macro_rules! type_combinations { ( $( $name:ident => { $( $tt:tt )* } );* $(;)? ) => { $( mod $name { $( $tt )* impl !Sync for Client {} impl !Send for Client {} } // Struct update syntax. This fails because the Client used in the update is considered // dropped *after* the yield. { let g = move || match drop($name::Client { ..$name::Client::default() }) { //~^ `significant_drop::Client` which is not `Send` //~| `insignificant_dtor::Client` which is not `Send` //~| `derived_drop::Client` which is not `Send` _ => yield, }; assert_send(g); //~^ ERROR cannot be sent between threads //~| ERROR cannot be sent between threads //~| ERROR cannot be sent between threads } // Simple owned value. This works because the Client is considered moved into `drop`, // even though the temporary expression doesn't end until after the yield. { let g = move || match drop($name::Client::default()) { _ => yield, }; assert_send(g); } )* } } fn assert_send(_thing: T) {} fn main() { type_combinations!( // OK copy => { #[derive(Copy, Clone, Default)] pub struct Client; }; // NOT OK: MIR borrowck thinks that this is used after the yield, even though // this has no `Drop` impl and only the drops of the fields are observable. // FIXME: this should compile. derived_drop => { #[derive(Default)] pub struct Client { pub nickname: String } }; // NOT OK significant_drop => { #[derive(Default)] pub struct Client; impl Drop for Client { fn drop(&mut self) {} } }; // NOT OK (we need to agree with MIR borrowck) insignificant_dtor => { #[derive(Default)] #[rustc_insignificant_dtor] pub struct Client; impl Drop for Client { fn drop(&mut self) {} } }; ); }