Function implementation_at

tests/integration/implementation.rs:11–38

(
    backend: &phpantom_lsp::Backend,
    uri: &Url,
    line: u32,
    character: u32,
)

// ─── Helpers ────────────────────────────────────────────────────────────────

async fn implementation_at(
    backend: &phpantom_lsp::Backend,
    uri: &Url,
    line: u32,
    character: u32,
) -> Vec<Location> {
    let params = GotoImplementationParams {
        text_document_position_params: TextDocumentPositionParams {
            text_document: TextDocumentIdentifier { uri: uri.clone() },
            position: Position { line, character },
        },
        work_done_progress_params: WorkDoneProgressParams::default(),
        partial_result_params: PartialResultParams::default(),
    };

    match backend.goto_implementation(params).await.unwrap() {
        Some(GotoImplementationResponse::Scalar(loc)) => vec![loc],
        Some(GotoImplementationResponse::Array(locs)) => locs,
        Some(GotoImplementationResponse::Link(links)) => links
            .into_iter()
            .map(|l| Location {
                uri: l.target_uri,
                range: l.target_selection_range,
            })
            .collect(),
        None => vec![],
    }
}

async fn open(backend: &phpantom_lsp::Backend, uri: &Url, text: &str) {
    backend