false positive for unnecessary_fold

[Wolvereness]

When using a boolean fold in a pattern guard (match { ... _ if values.iter().fold(false, |p, v| p || v.f()) =>), it suggests any.

This actually isn't applicable in this edge-case, as any requires a mutable-borrow on the iterator, which is completely unavailable in a pattern guard. fold happens to take the iterator by-value, which means it doesn't actually have any alternatives in a pattern guard.

[phansch]

This will probably be fixed with NLL soon: #3303 (comment). Going to leave this open until then.