error[E0390]: cannot define inherent `impl` for primitive types --> $DIR/E0390.rs:5:6 | LL | impl *mut Foo {} | ^^^^^^^^ | = help: consider using an extension trait instead error[E0390]: cannot define inherent `impl` for primitive types --> $DIR/E0390.rs:7:6 | LL | impl fn(Foo) {} | ^^^^^^^ | = help: consider using an extension trait instead error: aborting due to 2 previous errors For more information about this error, try `rustc --explain E0390`.