failure to infer move mode for a variable when the move is from *x

[nikomatsakis]

Example (play: http://is.gd/idpRaW)

use std::mem;
struct Trace;
fn foo(b: Box<Trace>) {
    do1(|| mem::drop(*b));
}
fn do1<F:FnOnce()>(f: F) { }
fn main() { }

If you change mem::drop(*b) to mem::drop(b), it compiles.

[bstrie]

Triage: still relevant.

[memoryruins]

Triage: now compiles on both editions.
rustc: 1.32.0

[matthewjasper]

The fix appears to have been in 1.23