{"record":{"id":"eff15ae021455a78","repo":"DioxusLabs/dioxus","slug":"visible-fragment-placement-requires-a-fallback-ins","errorCode":null,"errorMessage":"visible fragment placement requires a fallback insertion site","messagePattern":"visible fragment placement requires a fallback insertion site","errorType":"panic","errorClass":null,"httpStatus":null,"severity":"error","filePath":"packages/core/src/diff/iterator.rs","lineNumber":422,"sourceCode":"        }\n\n        let stable_edges = StableFragmentEdges::new(new, &new_mounts, &anchorable, self.dom);\n        for range in plan.placement_runs(&stable_edges.live_stable) {\n            let context = self.context();\n            let runtime = self.dom.runtime.clone();\n            let dom = &mut *self.dom;\n            let mut replaced_nodes = Vec::new();\n            if let Some(to) = self.to.as_deref_mut() {\n                let site = stable_edges\n                    .next_first(range.end)\n                    .map(InsertionSite::before)\n                    .or_else(|| {\n                        stable_edges\n                            .prev_last(range.start)\n                            .map(InsertionSite::after)\n                    })\n                    .or(fallback_site)\n                    .expect(\"visible fragment placement requires a fallback insertion site\");\n                site.create_and_place_with_result(to, runtime, |to| {\n                    let mut state = DiffState::new_with_context(dom, Some(to), context);\n                    let nodes = state.create_or_diff_placed_range(\n                        &inputs,\n                        &plan,\n                        range.clone(),\n                        &mut new_mounts,\n                        &mut replaced_nodes,\n                    );\n                    (nodes, nodes)\n                });\n            } else {\n                let mut state = DiffState::new_with_context(dom, None, context);\n                state.create_or_diff_placed_range(\n                    &inputs,\n                    &plan,\n                    range.clone(),\n                    &mut new_mounts,","sourceCodeStart":404,"sourceCodeEnd":440,"githubUrl":"https://github.com/DioxusLabs/dioxus/blob/24f6a829df0dfa203961a98ea4cae21c2ff27e28/packages/core/src/diff/iterator.rs#L404-L440","documentation":"Internal diffing invariant: a visible fragment placement run had no anchor element or fallback insertion site to insert relative to. Means the surrounding mounted tree is inconsistent with the diff plan.","triggerScenarios":"Thrown at packages/core/src/diff/iterator.rs:422 when the library encounters an invalid state.","commonSituations":"See trigger scenarios.","solutions":["This is an internal diffing invariant about fragment placement. Report it with a minimal reproduction to the Dioxus issue tracker."],"exampleFix":null,"handlingStrategy":"type-guard","validationCode":null,"typeGuard":null,"tryCatchPattern":null,"preventionTips":[],"tags":[],"backgroundTag":null,"analyzedSha":"24f6a829df0dfa203961a98ea4cae21c2ff27e28","analyzedAt":"2026-08-23T07:10:14.078Z","contentChangedAt":"2026-08-23T07:10:14.078Z","schemaVersion":2},"datasetVersion":"2026-09-14T05:17:10.506Z"}