error[E0277]: the trait bound `Option>: MyFromIterator<&u8>` is not satisfied --> $DIR/on-trait.rs:28:30 | LL | let y: Option> = collect(x.iter()); // this should give approximately the same error for x.iter().collect() | ^^^^^^^ a collection of type `Option>` cannot be built from an iterator over elements of type `&u8` | = help: the trait `MyFromIterator<&u8>` is not implemented for `Option>` help: this trait has no implementations, consider adding one --> $DIR/on-trait.rs:17:1 | LL | trait MyFromIterator { | ^^^^^^^^^^^^^^^^^^^^^^^ note: required by a bound in `collect` --> $DIR/on-trait.rs:22:39 | LL | fn collect, B: MyFromIterator>(it: I) -> B { | ^^^^^^^^^^^^^^^^^ required by this bound in `collect` error[E0277]: the trait bound `String: Foo` is not satisfied --> $DIR/on-trait.rs:31:21 | LL | let x: String = foobar(); | ^^^^^^ test error `String` with `u8` `_` `u32` in `Foo` | = help: the trait `Foo` is not implemented for `String` help: this trait has no implementations, consider adding one --> $DIR/on-trait.rs:7:3 | LL | pub trait Foo {} | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ note: required by a bound in `foobar` --> $DIR/on-trait.rs:12:24 | LL | fn foobar>() -> T { | ^^^^^^^^^^^^^^^ required by this bound in `foobar` error: aborting due to 2 previous errors For more information about this error, try `rustc --explain E0277`.