slint-ui/slint · error

Cannot set property {name}: {e}

Error message

Cannot set property {name}: {e}

What it means

Error "Cannot set property {name}: {e}" thrown in slint-ui/slint.

Source

Thrown at internal/live-preview/live_component.rs:140

            unreachable!("Compiler returned Pending")
        };
        Watcher::update_watched_paths(
            &self.watcher,
            std::iter::once(self.file_name.clone())
                .chain(result.watch_paths(i_slint_core::InternalToken).iter().cloned())
                .chain(self.extra_watch_paths.iter().cloned()),
        );
        result
    }

    /// Reload the properties and callbacks after a reload()
    pub fn reload_properties_and_callbacks(&self) {
        // Set the properties
        for (name, value) in self.properties.borrow_mut().iter() {
            if let Some((global, prop)) = name.split_once('.') {
                self.instance()
                    .set_global_property(global, prop, value.clone())
                    .unwrap_or_else(|e| panic!("Cannot set property {name}: {e}"));
            } else {
                self.instance()
                    .set_property(name, value.clone())
                    .unwrap_or_else(|e| panic!("Cannot set property {name}: {e}"));
            }
        }
        for (name, callback) in self.callbacks.borrow_mut().iter() {
            let callback = callback.clone();
            if let Some((global, prop)) = name.split_once('.') {
                self.instance()
                    .set_global_callback(global, prop, move |args| callback(args))
                    .unwrap_or_else(|e| panic!("Cannot set callback {name}: {e}"));
            } else {
                self.instance()
                    .set_callback(name, move |args| callback(args))
                    .unwrap_or_else(|e| panic!("Cannot set callback {name}: {e}"));
            }
        }

View on GitHub (pinned to 3fd8f2ec03)

Solutions

1. Check the nested error for the underlying cause and fix the property value type.
2. Ensure the property name exists on the live component.

When it happens

Trigger: Thrown at internal/live-preview/live_component.rs:140 when the library encounters an invalid state.

Common situations: See trigger scenarios.

AI-assisted analysis of slint-ui/slint@3fd8f2ec03 (2026-08-19). Data as JSON: /api/errors/ccca912c0ea85598. Report an issue: GitHub.