{"record":{"id":"aa7621db4eb0a37f","repo":"slint-ui/slint","slug":"failed-to-serialize","errorCode":null,"errorMessage":"Failed to serialize ()!","messagePattern":"Failed to serialize \\(\\)!","errorType":"panic","errorClass":null,"httpStatus":null,"severity":"info","filePath":"tools/lsp/language.rs","lineNumber":797,"sourceCode":"            )\n            .map_err(|_| LspError {\n                code: LspErrorCode::RequestFailed,\n                message: \"Failed to send populate edit\".into(),\n            })?\n            .await\n            .map_err(|_| LspError {\n                code: LspErrorCode::RequestFailed,\n                message: \"Failed to send populate edit\".into(),\n            })?;\n\n        if !response.applied {\n            return Err(LspError {\n                code: LspErrorCode::RequestFailed,\n                message: \"Failed to apply population edit\".into(),\n            });\n        }\n\n        Ok(serde_json::to_value(()).expect(\"Failed to serialize ()!\"))\n    })\n}\n\n/// Synchronous step in the host-language rename flow: classify the\n/// declaration the user just renamed, and -- if it is exposed in the\n/// generated Rust/C++ public API and the rename actually changes the\n/// accessor name -- spawn the async dialog + scanner + applyEdit follow-up.\n///\n/// The handler that calls this has already returned the slint-only\n/// `WorkspaceEdit` synchronously, so by the time the dialog appears the\n/// `.slint` file has already been updated by the client. The host-language\n/// scanner runs against the *old* accessor name on disk and produces a\n/// second `workspace/applyEdit` from the spawned task; the editor's\n/// undo/redo treats the two edits independently. That is intentional: if\n/// the user rejects the host-language rewrite (or the scanner errors),\n/// the slint rename still stands.\n#[cfg(not(target_arch = \"wasm32\"))]\nfn schedule_host_language_rename_followup(","sourceCodeStart":779,"sourceCodeEnd":815,"githubUrl":"https://github.com/slint-ui/slint/blob/bb937076de3f7919766c1f25e2e969367cf77e9a/tools/lsp/language.rs#L779-L815","documentation":"After successfully applying a populate/creation-data edit, the LSP handler for `populate_command` returns `Ok(serde_json::to_value(()).expect(\"Failed to serialize ()!\"))`, serializing the unit type as the JSON response. Unit type serialization is infallible in serde_json, so this expect is a tautological internal invariant; it can practically never fire and is not a real failure mode developers can trigger.","triggerScenarios":"In theory: serde_json being built with `arbitrary_precision`/`no_std`-style alloc feature configurations that alter serialization behavior; in practice, never under default features.","commonSituations":"Not observed in real usage; a panic here would indicate a broken/modified serde_json build rather than a user mistake.","solutions":["If it ever fires, verify the serde_json version and features match what slint-lsp was built against (no exotic feature flags).","Replace the expect with `serde_json::Value::Null` or `.unwrap_or(serde_json::Value::Null)` to remove the unreachable panic path.","Rebuild the LSP with a stock toolchain if a patched serde tree is in use."],"exampleFix":"// before\nOk(serde_json::to_value(()).expect(\"Failed to serialize ()!\"))\n\n// after\nOk(serde_json::Value::Null)","handlingStrategy":"try-catch","validationCode":null,"typeGuard":null,"tryCatchPattern":"// Not reachable in practice; if patching:\nmatch serde_json::to_value(()) {\n    Ok(v) => Ok(v),\n    Err(e) => Err(LspError { code: LspErrorCode::RequestFailed, message: format!(\"serialize failed: {e}\") }),\n}","preventionTips":["Use a stock serde_json version with default features when building slint-lsp.","Treat this panic as a signal of a non-standard serde build if it ever fires."],"tags":["lsp","serde","json","panic"],"backgroundTag":"json-marshal-failed","analyzedSha":"bb937076de3f7919766c1f25e2e969367cf77e9a","analyzedAt":"2026-09-16T01:37:20.251Z","contentChangedAt":"2026-09-16T01:37:20.251Z","schemaVersion":2},"datasetVersion":"2026-09-23T08:17:48.524Z"}