#![feature(associated_type_defaults)] struct S; mod method { trait A { fn a(&self) { } } pub trait B { fn b(&self) { } } pub trait C: A + B { fn c(&self) { } } impl A for ::S {} impl B for ::S {} impl C for ::S {} } mod assoc_const { trait A { const A: u8 = 0; } pub trait B { const B: u8 = 0; } pub trait C: A + B { const C: u8 = 0; } impl A for ::S {} impl B for ::S {} impl C for ::S {} } mod assoc_ty { trait A { type A = u8; } pub trait B { type B = u8; } pub trait C: A + B { type C = u8; } impl A for ::S {} impl B for ::S {} impl C for ::S {} } fn check_method() { // A is private // B is pub, not in scope // C : A + B is pub, in scope use method::C; // Methods, method call // a, b, c are resolved as trait items, their traits need to be in scope S.a(); //~ ERROR no method named `a` found S.b(); //~ ERROR no method named `b` found S.c(); // OK // a, b, c are resolved as inherent items, their traits don't need to be in scope let c = &S as &dyn C; c.a(); //~ ERROR method `a` is private c.b(); // OK c.c(); // OK // Methods, UFCS // a, b, c are resolved as trait items, their traits need to be in scope S::a(&S); //~^ ERROR no function or associated item named `a` found S::b(&S); //~^ ERROR no function or associated item named `b` found S::c(&S); // OK // a, b, c are resolved as inherent items, their traits don't need to be in scope <dyn C>::a(&S); //~ ERROR method `a` is private <dyn C>::b(&S); // OK C::c(&S); // OK } fn check_assoc_const() { // A is private // B is pub, not in scope // C : A + B is pub, in scope use assoc_const::C; // Associated constants // A, B, C are resolved as trait items, their traits need to be in scope S::A; //~ ERROR no associated item named `A` found S::B; //~ ERROR no associated item named `B` found S::C; // OK // A, B, C are resolved as inherent items, their traits don't need to be in scope <dyn C>::A; //~ ERROR associated constant `A` is private //~^ ERROR the trait `assoc_const::C` cannot be made into an object <dyn C>::B; // ERROR the trait `assoc_const::C` cannot be made into an object C::C; // OK } fn check_assoc_ty<T: assoc_ty::C>() { // A is private // B is pub, not in scope // C : A + B is pub, in scope use assoc_ty::C; // Associated types // A, B, C are resolved as trait items, their traits need to be in scope, not implemented yet let _: S::A; //~ ERROR ambiguous associated type let _: S::B; //~ ERROR ambiguous associated type let _: S::C; //~ ERROR ambiguous associated type // A, B, C are resolved as inherent items, their traits don't need to be in scope let _: T::A; //~ ERROR associated type `A` is private let _: T::B; // OK let _: T::C; // OK // Associated types, bindings let _: dyn assoc_ty::B< B = u8, // OK >; let _: dyn C< A = u8, //~ ERROR associated type `A` is private B = u8, // OK C = u8, // OK >; } fn main() {}