// revisions: base extended #![cfg_attr(extended, feature(generic_associated_types_extended))] #![cfg_attr(extended, allow(incomplete_features))] pub trait SubTrait {} pub trait SuperTrait { type SubType<'a>: SubTrait where Self: 'a; fn get_sub<'a>(&'a mut self) -> Self::SubType<'a>; } pub struct SubStruct<'a> { sup: &'a mut SuperStruct, } impl<'a> SubTrait for SubStruct<'a> {} pub struct SuperStruct { value: u8, } impl SuperStruct { pub fn new(value: u8) -> SuperStruct { SuperStruct { value } } } impl SuperTrait for SuperStruct { type SubType<'a> = SubStruct<'a>; fn get_sub<'a>(&'a mut self) -> Self::SubType<'a> { SubStruct { sup: self } } } fn main() { let sub: Box> = Box::new(SuperStruct::new(0)); //~^ ERROR missing generics for associated type //[base]~^^ ERROR the trait //[base]~| ERROR the trait }