error[E0284]: type annotations needed --> $DIR/object-safety-ok-infer-err.rs:19:5 | LL | use_dyn(&()); | ^^^^^^^ cannot infer the value of the const parameter `N` declared on the function `use_dyn` | note: required by a bound in `use_dyn` --> $DIR/object-safety-ok-infer-err.rs:14:55 | LL | fn use_dyn(v: &dyn Foo) where [u8; N + 1]: Sized { | ^^^^^ required by this bound in `use_dyn` help: consider specifying the generic argument | LL | use_dyn::(&()); | +++++ error: aborting due to previous error For more information about this error, try `rustc --explain E0284`.