zed-industries/zed · error

you can't prepaint LineWithInvisibles twice

Error message

you can't prepaint LineWithInvisibles twice

What it means

A one-shot lifecycle invariant: LineWithInvisibles::prepaint computes and caches per-line layout state, and painting a line prepaints it exactly once per frame. The expect fires when the same LineWithInvisibles element is prepainted twice — usually an element was reused across two paint passes or added to two parents — indicating a framework usage bug rather than bad data.

Source

Thrown at crates/editor/src/element.rs:7542

            line_elements,
            window,
            cx,
        );
    }

    fn prepaint_with_custom_offset(
        &mut self,
        line_height: Pixels,
        scroll_pixel_position: gpui::Point<ScrollPixelOffset>,
        content_origin: gpui::Point<Pixels>,
        line_y: Pixels,
        line_elements: &mut SmallVec<[AnyElement; 1]>,
        window: &mut Window,
        cx: &mut App,
    ) {
        let mut fragment_origin =
            content_origin + gpui::point(Pixels::from(-scroll_pixel_position.x), line_y);
        for fragment in &mut self.fragments {
            match fragment {
                LineFragment::Text(line) => {
                    fragment_origin.x += line.width;
                }
                LineFragment::Element { element, size, .. } => {
                    let mut element = element
                        .take()
                        .expect("you can't prepaint LineWithInvisibles twice");

                    // Center the element vertically within the line.
                    let mut element_origin = fragment_origin;
                    element_origin.y += (line_height - size.height) / 2.;
                    element.prepaint_at(element_origin, window, cx);
                    line_elements.push(element);

                    fragment_origin.x += size.width;
                }
            }

View on GitHub (pinned to 9d272b0363)

Solutions

1. Construct a fresh LineWithInvisibles per prepaint site instead of reusing a prepared element
2. Track a 'prepainted' flag and no-op (or rebuild) on a second prepaint rather than panicking
3. Audit callers that clone or re-add prepared line elements to multiple element trees

When it happens

Trigger: Thrown at crates/editor/src/element.rs:7440 when the library encounters an invalid state.

Common situations: See trigger scenarios.

AI-assisted analysis of zed-industries/zed@9d272b0363 (2026-08-20). Data as JSON: /api/errors/9ce33a4058600d57. Report an issue: GitHub.