lifetimes.rs

// Question: is there any way to fix this function using lifetimes (as the error message would suggest)?                                                       
                                                                                
use std::iter::Map;                                                             
use std::vec::Items;                                                            
                                                                                
fn main () {}                                                                   
                                                                                
fn f<'r>(items: Items<'r, u8>) -> Map<&u8, u8, Items<'r, u8>> {                 
    items.map(|&x| x)                                                           
}                                                                               
                                                                                
/*                                                                              
Generates typical lifetimes error message:                                      
                                                                                
lifetimes.rs:9:5: 9:10 error: cannot infer an appropriate lifetime for region in type/impl due to conflicting requirements
lifetimes.rs:9     items.map(|&x| x)
                   ^~~~~
lifetimes.rs:8:63: 10:2 note: first, the lifetime cannot outlive the anonymous lifetime #2 defined on the block at 8:62...
lifetimes.rs:8 fn f<'r>(items: Items<'r, u8>) -> Map<&u8, u8, Items<'r, u8>> {
lifetimes.rs:9     items.map(|&x| x)
lifetimes.rs:10 }
lifetimes.rs:9:5: 9:22 note: ...so that types are compatible (expected `std::iter::Map<,&u8,u8,std::vec::Items<'r,u8>>` but found `std::iter::Map<,&u8,u8,std::vec::Items<,u8>>`)
lifetimes.rs:9     items.map(|&x| x)
                   ^~~~~~~~~~~~~~~~~
lifetimes.rs:8:63: 10:2 note: but, the lifetime must be valid for the lifetime &'r  as defined on the block at 8:62...
lifetimes.rs:8 fn f<'r>(items: Items<'r, u8>) -> Map<&u8, u8, Items<'r, u8>> {
lifetimes.rs:9     items.map(|&x| x)
lifetimes.rs:10 }
lifetimes.rs:9:5: 9:22 note: ...so that types are compatible (expected `std::iter::Map<,&u8,u8,std::vec::Items<'r,u8>>` but found `std::iter::Map<,&u8,u8,std::vec::Items<,u8>>`)
lifetimes.rs:9     items.map(|&x| x)
                   ^~~~~~~~~~~~~~~~~
error: aborting due to previous error
*/