error[E0282]: type annotations needed --> $DIR/fallback_inference.rs:4:5 | LL | PhantomData | ^^^^^^^^^^^ cannot infer type of the type parameter `T` declared on the struct `PhantomData` | help: consider specifying the generic argument | LL | PhantomData:: | +++++ error: aborting due to 1 previous error For more information about this error, try `rustc --explain E0282`.