| error[E0283]: type annotations needed |
| --> $DIR/sort_by_key.rs:3:40 |
| | |
| LL | lst.sort_by_key(|&(v, _)| v.iter().sum()); |
| | ----------- ^^^ cannot infer type of the type parameter `S` declared on the method `sum` |
| | | |
| | type must be known at this point |
| | |
| = note: cannot satisfy `_: Ord` |
| note: required by a bound in `slice::<impl [T]>::sort_by_key` |
| --> $SRC_DIR/alloc/src/slice.rs:LL:COL |
| help: consider specifying the generic argument |
| | |
| LL | lst.sort_by_key(|&(v, _)| v.iter().sum::<S>()); |
| | +++++ |
| |
| error: aborting due to previous error |
| |
| For more information about this error, try `rustc --explain E0283`. |
