error[E0277]: the trait bound `{integer}: Scalar` is not satisfied
  --> $DIR/issue-22645.rs:15:5
   |
LL |   b + 3
   |     ^ the trait `Scalar` is not implemented for `{integer}`, which is required by `Bob: Add<_>`
   |
   = help: the trait `Scalar` is implemented for `f64`
note: required for `Bob` to implement `Add<{integer}>`
  --> $DIR/issue-22645.rs:8:19
   |
LL | impl<RHS: Scalar> Add <RHS> for Bob {
   |           ------  ^^^^^^^^^     ^^^
   |           |
   |           unsatisfied trait bound introduced here

error[E0308]: mismatched types
  --> $DIR/issue-22645.rs:15:3
   |
LL | fn main() {
   |          - expected `()` because of default return type
LL |   let b = Bob + 3.5;
LL |   b + 3
   |   ^^^^^ expected `()`, found `Bob`

error: aborting due to 2 previous errors

Some errors have detailed explanations: E0277, E0308.
For more information about an error, try `rustc --explain E0277`.