Borrow checker works wrongly with returned values.

[loyd]

Unfortunately I haven't found an open bug on this subject.

I tried this code:

struct A(Vec<u32>);

impl A {
    fn drain(self) -> Vec<u32> {
        let mut nums = self.0;
        nums.drain(..).collect()          // error: `nums` does not live long enough

        // but it works fine:
        // return nums.drain(..).collect();
    }
}

Try it

[jonas-schievink]

I think this is #21114

[TimNN]

Essentially the same issue as #31723, I think.

Edit: (why weren't you auto updating the comments, github?) @jonas-schievink's issue is probably the "better" duplicate.

[Mark-Simulacrum]

Closing in favor of #21114. Please reopen if that's incorrect, but from what I can tell this is a duplicate of that issue.