error[E0277]: the trait bound `Option<Vec<u8>>: MyFromIterator<&u8>` is not satisfied
  --> $DIR/on-trait.rs:28:30
   |
LL | fn collect<A, I: Iterator<Item=A>, B: MyFromIterator<A>>(it: I) -> B {
   |                                       ----------------- required by this bound in `collect`
...
LL |     let y: Option<Vec<u8>> = collect(x.iter()); // this should give approximately the same error for x.iter().collect()
   |                              ^^^^^^^ a collection of type `Option<Vec<u8>>` cannot be built from an iterator over elements of type `&u8`
   |
   = help: the trait `MyFromIterator<&u8>` is not implemented for `Option<Vec<u8>>`

error[E0277]: the trait bound `String: Foo<u8, _, u32>` is not satisfied
  --> $DIR/on-trait.rs:31:21
   |
LL | fn foobar<U: Clone, T: Foo<u8, U, u32>>() -> T {
   |                        --------------- required by this bound in `foobar`
...
LL |     let x: String = foobar();
   |                     ^^^^^^ test error `String` with `u8` `_` `u32` in `Foo`
   |
   = help: the trait `Foo<u8, _, u32>` is not implemented for `String`

error: aborting due to 2 previous errors

For more information about this error, try `rustc --explain E0277`.