1 A lifetime appears only in an associated-type binding,
2 and not in the input types to the trait.
4 Erroneous code example:
8 // No type can satisfy this requirement, since `'a` does not
9 // appear in any of the input types (here, `i32`):
10 where F: for<'a> Fn(i32) -> Option<&'a i32>
17 To fix this issue, either use the lifetime in the inputs, or use
21 fn bar<F, G>(t: F, u: G)
22 where F: for<'a> Fn(&'a i32) -> Option<&'a i32>,
23 G: Fn(i32) -> Option<&'static i32>,
30 Note: The examples above used to be (erroneously) accepted by the
31 compiler, but this was since corrected. See [issue #33685] for more
34 [issue #33685]: https://github.com/rust-lang/rust/issues/33685