to_item: the trait bound `!: std::convert::From<serde_dynamo::Item>` is not satisfied

[wilfredjonathanjames]

serde_dynamo@4.3.0

Using the enum example given here, I'm seeing a trait bound error on to_item:

1. the trait bound `!: std::convert::From<serde_dynamo::Item>` is not satisfied
  the trait `std::convert::From<serde_dynamo::Item>` is not implemented for `!` [E0277]

The same thing when using the example given here.

Using the 2021 edition yields a slightly different error:

1. the trait bound `(): std::convert::From<serde_dynamo::Item>` is not satisfied
   the trait `From<serde_dynamo::Item>` is not implemented for `()`
   but trait `From<aws_lc_rs::error::Unspecified>` is implemented for it
   for that trait implementation, expected `aws_lc_rs::error::Unspecified`, found `serde_dynamo::Item` [E0277]

Either way, I'm not sure how to proceed. My own code has the same issue as the examples I have tried.

[Edit]
I've answered my own question. the item must be given the type serde_dynamo::Item.

  let item: Item = to_item(data)?;

Leaving open because it seems the docs need updating.

[Edit Edit]
It turns out the correct type is not Item but

HashMap<String, AttributeValue>

And I needed to use the feature flag aws-sdk-dynamodb+1

Would love it if someone could point out where this is mentioned in the documentation.