DioxusLabs/dioxus · error

dynamic child checked

Error message

dynamic child checked

What it means

The merged static/dynamic child iterator compares peeked heads and `expect`s the dynamic child to still be present when taking it. This panic fires only if the iterator's internal bookkeeping is wrong (taking an already-consumed head) — an internal bug, not user error.

Source

Thrown at packages/core/src/diff/template.rs:283

            next_static,
            next_dynamic,
        }
    }

    fn next(&mut self) -> Option<VNodeChild<'a>> {
        let take_static = match (self.next_static, self.next_dynamic) {
            (Some(static_child), Some(dynamic_child)) => static_child.key() <= dynamic_child.key(),
            (Some(_), None) => true,
            (None, Some(_)) => false,
            (None, None) => return None,
        };

        if take_static {
            let child = self.next_static.take().expect("static child checked");
            self.next_static = self.static_children.next();
            Some(child.child)
        } else {
            let child = self.next_dynamic.take().expect("dynamic child checked");
            self.next_dynamic = self.dynamic_children.next();
            Some(child.child)
        }
    }
}

#[derive(Clone, Copy)]
struct PositionedChild<'a> {
    position: usize,
    order: usize,
    child: VNodeChild<'a>,
}

impl<'a> PositionedChild<'a> {
    fn key(self) -> (usize, usize) {
        (self.position, self.order)
    }
}

View on GitHub (pinned to 24f6a829df)

Solutions

1. This is an internal invariant about dynamic children. Report it with a minimal reproduction to the Dioxus issue tracker.

When it happens

Trigger: Thrown at packages/core/src/diff/template.rs:283 when the library encounters an invalid state.

Common situations: See trigger scenarios.

AI-assisted analysis of DioxusLabs/dioxus@24f6a829df (2026-08-23). Data as JSON: /api/errors/03f9455a7ce70d96. Report an issue: GitHub.