|  | error: lifetime may not live long enough | 
|  | --> $DIR/variance-cell-is-invariant.rs:14:12 | 
|  | | | 
|  | LL | fn use_<'short,'long>(c: Foo<'short>, | 
|  | |         ------ ----- lifetime `'long` defined here | 
|  | |         | | 
|  | |         lifetime `'short` defined here | 
|  | ... | 
|  | LL |     let _: Foo<'long> = c; | 
|  | |            ^^^^^^^^^^ type annotation requires that `'short` must outlive `'long` | 
|  | | | 
|  | = help: consider adding the following bound: `'short: 'long` | 
|  | = note: requirement occurs because of the type `Foo<'_>`, which makes the generic argument `'_` invariant | 
|  | = note: the struct `Foo<'a>` is invariant over the parameter `'a` | 
|  | = help: see <https://doc.rust-lang.org/nomicon/subtyping.html> for more information about variance | 
|  |  | 
|  | error: aborting due to 1 previous error | 
|  |  |