rust/tests/ui/traits/trait-upcasting/subtrait-method.rs

#![feature(trait_upcasting)]

trait Foo: PartialEq<i32> + std::fmt::Debug + Send + Sync {
    fn a(&self) -> i32 {
        10
    }

    fn z(&self) -> i32 {
        11
    }

    fn y(&self) -> i32 {
        12
    }
}

trait Bar: Foo {
    fn b(&self) -> i32 {
        20
    }

    fn w(&self) -> i32 {
        21
    }
}

trait Baz: Bar {
    fn c(&self) -> i32 {
        30
    }
}

impl Foo for i32 {
    fn a(&self) -> i32 {
        100
    }
}

impl Bar for i32 {
    fn b(&self) -> i32 {
        200
    }
}

impl Baz for i32 {
    fn c(&self) -> i32 {
        300
    }
}

fn main() {
    let baz: &dyn Baz = &1;

    let bar: &dyn Bar = baz;
    bar.c();
    //~^ ERROR no method named `c` found for reference `&dyn Bar` in the current scope [E0599]

    let foo: &dyn Foo = baz;
    foo.b();
    //~^ ERROR no method named `b` found for reference `&dyn Foo` in the current scope [E0599]
    foo.c();
    //~^ ERROR no method named `c` found for reference `&dyn Foo` in the current scope [E0599]

    let foo: &dyn Foo = bar;
    foo.b();
    //~^ ERROR no method named `b` found for reference `&dyn Foo` in the current scope [E0599]
    foo.c();
    //~^ ERROR no method named `c` found for reference `&dyn Foo` in the current scope [E0599]
}