Answer stability round 1: 1 🔴, 0 🟡 (0 misread); register one test per case, and file the runEdge give-up

src/markdown/emit/unspellable-runs.test.ts

@@ -2,6 +2,7 @@ import assert from 'node:assert/strict'
 import test from 'node:test'
 
 import type { NodeRange } from './line-escaping.ts'
+import type { RunGrouping } from './inline-runs.ts'
 import { isAdfMark, type AdfMark, type AdfNode } from '../../adf/document.ts'
 import { linePass, withheldMarkFallbacks } from './inline-line.ts'
 import { portableJudgement, portableLeaves } from '../portable/inline-reduction.ts'
@@ -78,24 +79,26 @@ const lines: { carry?: string[]; drop?: string[]; name: string; nodes: AdfNode[]
 ]
 
 for (const { carry, drop, name, nodes } of lines) {
-  test(`unspellableRuns returns ${name}`, () => {
-    for (const grouping of ['spanned', 'parted'] as const) {
-      if (carry !== undefined) {
-        const pass = linePass(nodes, 'paragraph', [], withheldMarkFallbacks(nodes, 'lossless'), grouping)
-        assert.ok(pass.ok)
-        assert.ok(pass.value.fallback !== undefined && pass.value.fallback !== 'opening-link')
-        assert.deepEqual(named(pass.value.fallback), carry)
-      }
-      if (drop !== undefined) {
-        const leaves = portableLeaves(nodes, 'paragraph', { depth: 0, path: [], sources: new Map() })
-        assert.ok(leaves.ok)
-        const judged = portableJudgement(leaves.value, grouping, 'paragraph', [])
-        assert.ok(judged.ok)
-        assert.ok(judged.value.kind === 'fallback' && judged.value.fallback.kind === 'unspellable-run')
-        assert.deepEqual(named(judged.value.fallback.runs), drop)
-      }
-    }
-  })
+  for (const grouping of ['spanned', 'parted'] as const) {
+    if (carry !== undefined) test(`${grouping} line of ${name}: a carry takes ${carry.join(', ')}`, () => assert.deepEqual(carryRuns(nodes, grouping), carry))
+    if (drop !== undefined) test(`${grouping} line of ${name}: a drop takes ${drop.join(', ')}`, () => assert.deepEqual(dropRuns(nodes, grouping), drop))
+  }
+}
+
+function carryRuns(nodes: readonly AdfNode[], grouping: RunGrouping): string[] {
+  const pass = linePass(nodes, 'paragraph', [], withheldMarkFallbacks(nodes, 'lossless'), grouping)
+  assert.ok(pass.ok)
+  assert.ok(pass.value.fallback !== undefined && pass.value.fallback !== 'opening-link')
+  return named(pass.value.fallback)
+}
+
+function dropRuns(nodes: readonly AdfNode[], grouping: RunGrouping): string[] {
+  const leaves = portableLeaves(nodes, 'paragraph', { depth: 0, path: [], sources: new Map() })
+  assert.ok(leaves.ok)
+  const judged = portableJudgement(leaves.value, grouping, 'paragraph', [])
+  assert.ok(judged.ok)
+  assert.ok(judged.value.kind === 'fallback' && judged.value.fallback.kind === 'unspellable-run')
+  return named(judged.value.fallback.runs)
 }
 
 function marked(types: readonly string[], text: string): AdfNode {

todo.md

@@ -6,7 +6,7 @@
 
 `Bar = 0.1`
 
-`Next ID = 176`
+`Next ID = 177`
 
 ## Items
 
@@ -14,6 +14,7 @@
 |---|---|---|---|---|---|---|---|---|---|---|---|
 | 153 | 0.4.0 |  | question | **Decide whether `src/markdown/` root may import `emit/`, `parse/` or `portable/`, and hold the answer in `.oxlintrc.json` and §The source parts by ADF and format.** | 1 | 2 | 2 | 3 | 2 | code health by 3 | 26.2 |
 | 175 | 0.4.0 |  |  | **Delete the guards in `tryTaskList` that `reduceToPortable` makes unreachable, once a test shows `adfToPortableMarkdown` reaches none of them.** | 1 | 1 | 1 | 1 | 2 | code health by 2 | 17.4 |
+| 176 | 0.4.0 |  |  | **Delete `runEdge`'s `standing === 'moves'` give-up, and any code only it needs, once a test or an argument shows `runEdge` never reaches it, or else pin the case with a hand-worked line.** | 1 | 1 | 2 | 2 | 2 | code health by 2 | 17.4 |
 | 45 | 0.4.0 |  | defect | **Replace `isAdfDocument` with a reader returning `Result<AdfDocument>`.** | 2 | 1 | 3 | 4 | 3 | 1 by 2 | 13.1 |
 | 127 | 0.4.0 |  | principle | **Hold what `entity-references.test.ts`, `json-text.test.ts` and `result.test.ts` check by asserting outcomes, so none reads source text.** | 2 | 2 | 1 | 3 | 3 | code health by 2 | 13.1 |
 | 159 | 0.4.0 |  |  | **Delete `taskBlocks`'s branch that writes the task marker as its own paragraph, once a test shows no block task item reaches it.** | 1 | 1 | 1 | 1 | 1 | code health by 1 | 10.5 |
@@ -80,6 +81,13 @@ files, with its `ci.sh` probe, extends the decision.
 nesting refusal's path comes from `reduceToPortable`. Found by mutation testing for item 128,
 2026-11-08.
 
+### 176. Delete `runEdge`'s `standing === 'moves'` give-up, and any code only it needs, once a test or an argument shows `runEdge` never reaches it, or else pin the case with a hand-worked line.
+
+In `src/markdown/emit/unspellable-runs.ts`, Stryker's mutants of `runEdge`'s
+`if (standing === 'moves') return undefined` survive the hand-worked tests, and 50,000 fuzz runs
+comparing the code with the mutant found no output differ. Found on PR 145, 2026-11-09. The
+comprehension seats found `runEdge` hard to read (`larv-review places`); make it easier.
+
 ### 45. Replace `isAdfDocument` with a reader returning `Result<AdfDocument>`.
 
 Lands with item 77: the reader returns item 77's copy. Goal 1 has every call return a result; the