trait Foo { fn a(&self) -> i32 { 10 } fn z(&self) -> i32 { 11 } fn y(&self) -> i32 { 12 } } trait Bar { fn b(&self) -> i32 { 20 } fn w(&self) -> i32 { 21 } } trait Baz { 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 _: &dyn std::fmt::Debug = baz; //~^ ERROR mismatched types [E0308] let _: &dyn Send = baz; //~^ ERROR mismatched types [E0308] let _: &dyn Sync = baz; //~^ ERROR mismatched types [E0308] let bar: &dyn Bar = baz; //~^ ERROR mismatched types [E0308] let _: &dyn std::fmt::Debug = bar; //~^ ERROR mismatched types [E0308] let _: &dyn Send = bar; //~^ ERROR mismatched types [E0308] let _: &dyn Sync = bar; //~^ ERROR mismatched types [E0308] let foo: &dyn Foo = baz; //~^ ERROR mismatched types [E0308] let _: &dyn std::fmt::Debug = foo; //~^ ERROR mismatched types [E0308] let _: &dyn Send = foo; //~^ ERROR mismatched types [E0308] let _: &dyn Sync = foo; //~^ ERROR mismatched types [E0308] let foo: &dyn Foo = bar; //~^ ERROR mismatched types [E0308] let _: &dyn std::fmt::Debug = foo; //~^ ERROR mismatched types [E0308] let _: &dyn Send = foo; //~^ ERROR mismatched types [E0308] let _: &dyn Sync = foo; //~^ ERROR mismatched types [E0308] }