| use std::ops::ControlFlow; | 
 |  | 
 | fn result_to_result() -> Result<u64, u8> { | 
 |     Ok(Err(123_i32)?) | 
 |     //~^ ERROR `?` couldn't convert the error to `u8` | 
 | } | 
 |  | 
 | fn option_to_result() -> Result<u64, String> { | 
 |     Some(3)?; | 
 |     //~^ ERROR the `?` operator can only be used on `Result`s, not `Option`s, in a function that returns `Result` | 
 |     Ok(10) | 
 | } | 
 |  | 
 | fn control_flow_to_result() -> Result<u64, String> { | 
 |     Ok(ControlFlow::Break(123)?) | 
 |     //~^ ERROR the `?` operator can only be used on `Result`s in a function that returns `Result` | 
 | } | 
 |  | 
 | fn result_to_option() -> Option<u16> { | 
 |     Some(Err("hello")?) | 
 |     //~^ ERROR the `?` operator can only be used on `Option`s, not `Result`s, in a function that returns `Option` | 
 | } | 
 |  | 
 | fn control_flow_to_option() -> Option<u64> { | 
 |     Some(ControlFlow::Break(123)?) | 
 |     //~^ ERROR the `?` operator can only be used on `Option`s in a function that returns `Option` | 
 | } | 
 |  | 
 | fn result_to_control_flow() -> ControlFlow<String> { | 
 |     ControlFlow::Continue(Err("hello")?) | 
 |     //~^ ERROR the `?` operator can only be used on `ControlFlow`s in a function that returns `ControlFlow` | 
 | } | 
 |  | 
 | fn option_to_control_flow() -> ControlFlow<u64> { | 
 |     Some(3)?; | 
 |     //~^ ERROR the `?` operator can only be used on `ControlFlow`s in a function that returns `ControlFlow` | 
 |     ControlFlow::Break(10) | 
 | } | 
 |  | 
 | fn control_flow_to_control_flow() -> ControlFlow<i64> { | 
 |     ControlFlow::Break(4_u8)?; | 
 |     //~^ ERROR the `?` operator in a function that returns `ControlFlow<B, _>` can only be used on other `ControlFlow<B, _>`s | 
 |     ControlFlow::Continue(()) | 
 | } | 
 |  | 
 | fn main() {} |