error[E0277]: the trait bound `{integer}: Scalar` is not satisfied
  --> $DIR/issue-22645.rs:25:5
   |
LL |   b + 3 //~ ERROR E0277
   |     ^ the trait `Scalar` is not implemented for `{integer}`
   |
   = help: the following implementations were found:
             <f64 as Scalar>
   = note: required because of the requirements on the impl of `std::ops::Add<{integer}>` for `Bob`

error[E0308]: mismatched types
  --> $DIR/issue-22645.rs:25:3
   |
LL | fn main() {
   |           - expected `()` because of default return type
LL |   let b = Bob + 3.5;
LL |   b + 3 //~ ERROR E0277
   |   ^^^^^ expected (), found struct `Bob`
   |
   = note: expected type `()`
              found type `Bob`

error: aborting due to 2 previous errors

You've got a few errors: E0277, E0308
If you want more information on an error, try using "rustc --explain E0277"