error[E0282]: type annotations needed for `&_`
--> tests/ui/inference/fail_unannotated.rs:8:19
|
8 | let _ = grad(|x| x.sum())(&x);
| ^ - type must be known at this point
|
help: consider giving this closure parameter an explicit type, where the type for type parameter `P` is specified
|
8 | let _ = grad(|x: &P| x.sum())(&x);
| ++++