iter() -> into_iter()

What it does

Propose to change iter() to into_iter()

Categories (optional)

• Kind: See https://github.com/rust-lang/rust-clippy/blob/master/README.md#clippy for list of lint kinds

What is the advantage of the recommended code over the original code

For example:

My old code:
foo.unwrap_or_default().iter()....
By hand I changed it to:
foo.unwrap_or_default().into_iter()....
Then clippy proposed to remove some clone()s
When I removed the clone()s, clippy proposed to change filter + map to filter_map
clippy is awesome. The code looks beautiful now.

The suggestion to change iter() to into_iter() was missing and blocking the other lints

Drawbacks

None.

Example

foo.unwrap_or_default().iter()....

Could be written as:

foo.unwrap_or_default().into_iter()....

The issue names no implementation files, tests, or entry points. Start by reviewing existing Clippy iterator-related lints and their tests, then determine the cases where replacing iter() with into_iter() is valid. Done means the intended cases are linted without changing semantics and the follow-up lints can apply.