Function merge_data_class_names

src/completion/builder.rs:685–703

Merge the class name from a new item's `data` into the existing item's `data.extra_class_names` so that `completionItem/resolve` can iterate all union branches when building hover documentation.

(existing: &mut CompletionItem, new_item: &CompletionItem)

/// `data.extra_class_names` so that `completionItem/resolve` can iterate
/// all union branches when building hover documentation.
fn merge_data_class_names(existing: &mut CompletionItem, new_item: &CompletionItem) {
    let (Some(existing_data), Some(new_data)) = (&existing.data, &new_item.data) else {
        return;
    };
    let (Ok(mut ed), Ok(nd)) = (
        serde_json::from_value::<CompletionItemData>(existing_data.clone()),
        serde_json::from_value::<CompletionItemData>(new_data.clone()),
    ) else {
        return;
    };
    // Skip if the class name is already recorded.
    if ed.class_name == nd.class_name || ed.extra_class_names.contains(&nd.class_name) {
        return;
    }
    ed.extra_class_names.push(nd.class_name.clone());
    if let Ok(v) = serde_json::to_value(&ed) {
        existing.data = Some(v);
    }
}

/// Extract the class name(s) from a `CompletionItem`'s `data` field.
///