1 error[E0282]: type annotations needed for `Option<_>`
2 --> $DIR/issue-42234-unknown-receiver-type.rs:10:7
4 LL | let x: Option<_> = None;
5 | - consider giving `x` the explicit type `Option<_>`, where the type parameter `T` is specified
6 LL | x.unwrap().method_that_could_exist_on_some_type();
7 | ^^^^^^ cannot infer type for type parameter `T`
9 = note: type must be known at this point
11 error[E0282]: type annotations needed
12 --> $DIR/issue-42234-unknown-receiver-type.rs:16:16
15 | ^ cannot infer type for type parameter `S` declared on the associated function `sum`
17 = note: type must be known at this point
19 error: aborting due to 2 previous errors
21 For more information about this error, try `rustc --explain E0282`.