Lifetimes should be inferred in simple cases

[steveklabnik]

Issue by mhart
Tuesday Nov 04, 2014 at 18:07 GMT

For earlier discussion, see rust-lang/rust#18620

This issue was labelled with: in the Rust repository

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Rust newbie here. This is very probably a dupe, but my GH foo failed me.

The following fails to compile:

fn my_fn<T>(items: T) where T: Iterator<&str> {
    println!("hello")
}

With:

<anon>:5:41: 5:45 error: missing lifetime specifier [E0106]
<anon>:5 fn my_fn<T>(items: T) where T: Iterator<&str> {
                                                 ^~~~

But it's unclear to me why the compiler can't just infer the lifetime here?

Shouldn't this be the default choice?

fn my_fn<'a, T>(items: T) where T: Iterator<&'a str> {
    println!("hello")
}

Edit: So it could also be 'static, but I wouldn't have thought that would be the default (or encouraged) case. If you did want it to be static, then you could declare it explicitly. Similar to how variables are immutable by default (without needing an explicit declaration), yet if you want them to be mutable you declare it.

[Centril]

Closing in favor of #1352.