rust-lang/rust-analyzer · error

unable to get FileId

Error message

unable to get FileId

What it means

CheckIfIndexed deferred task converts a file URI into an internal FileId and only then checks index status. The code already handles None gracefully via if-let, so the expect fires only when from_proto::file_id returns Err — i.e. the URI cannot be converted (unsupported scheme such as untitled:/, or URL parsing failure). Since the error case is otherwise handled, this expect is an over-strict assertion on an unreachable-in-practice branch.

Source

Thrown at crates/rust-analyzer/src/main_loop.rs:1091

                            Some(message),
                            Some(Progress::fraction(n_done, n_total)),
                            None,
                        )
                    }
                }
            }
        }
    }

    fn handle_deferred_task(&mut self, task: DeferredTask) {
        match task {
            DeferredTask::CheckIfIndexed(uri) => {
                let snap = self.snapshot();

                self.task_pool.handle.spawn_with_sender(ThreadIntent::Worker, move |sender| {
                    let _p = tracing::info_span!("GlobalState::check_if_indexed").entered();
                    tracing::debug!(?uri, "handling uri");
                    let Some(id) = from_proto::file_id(&snap, &uri).expect("unable to get FileId")
                    else {
                        return;
                    };
                    if let Ok(crates) = &snap.analysis.crates_for(id) {
                        if crates.is_empty() {
                            if snap.config.discover_workspace_config().is_some() {
                                let path =
                                    from_proto::abs_path(&uri).expect("Unable to get AbsPath");
                                let arg = DiscoverProjectParam::Path(path);
                                sender.send(Task::DiscoverLinkedProjects(arg)).unwrap();
                            }
                        } else {
                            tracing::debug!(?uri, "is indexed");
                        }
                    }
                });
            }
            DeferredTask::CheckProcMacroSources(modified_rust_files) => {

View on GitHub (pinned to e8f7e90aa3)

Solutions

1. Avoid running rust-analyzer analysis over virtual/untitled URIs, or save the file to disk first.
2. Upgrade rust-analyzer — this branch should map Err to the existing `return` path instead of panicking.
3. Identify which extension/client produced the URI from logs (the `?uri` debug field) and disable the offending virtual-document provider for .rs files.
4. As a workaround, disable workspace linking/deferred indexing on that URI by closing the virtual editor.

Example fix

// before
let Some(id) = from_proto::file_id(&snap, &uri).expect("unable to get FileId") else { return; };
// after: treat conversion error like the not-found case
let Ok(id) = from_proto::file_id(&snap, &uri) else { return; };

// server-side guard: skip non-file URIs before the deferred task
if uri.scheme().as_str() != "file" { return; }

fn is_file_uri(uri: &lsp_types::Url) -> bool {
    uri.scheme() == "file"
}

// if you cannot patch the server, avoid triggering it client-side
if (doc.uri.scheme !== 'file') { return; } // don't expect indexing for untitled/virtual docs

When it happens

Trigger: A textDocument URI with a non-file scheme (untitled:, vscode-notebook-cell:, remote authority prefixes) or a malformed URI reaching the CheckIfIndexed task after didOpen/didChange, causing from_proto::file_id to return Err instead of Ok(None).

Common situations: Editing untitled scratch files, remote/SSH or web (VS Code web) development where URIs carry non-standard schemes, extensions that synthesize virtual document URIs, and notebooks embedding Rust code.

Related errors

• Unable to get AbsPath
• received response for unknown request
• we never provide completions for excluded files
• we never provide code actions for excluded files
• No title could be found; this is a bug

AI-assisted analysis of rust-lang/rust-analyzer@e8f7e90aa3 (2026-09-03). Data as JSON: /api/errors/8ac9b35de867a5dc. Report an issue: GitHub.