Context
Here is an example of this issue:
open-component-model/open-component-model#448

If an error is returned in a defer-statement
e.g.

defer func() {
    err = errors.Join(err, ...)
}()

If the error in the assignment is not a named return parameter, the above code does not do anything.

Additional Comments
We have a lot of places in our code like the example given above (typically, we check for io close errors in the defer). We have to find these places and fix them.