fix(cli): a dangling nested requirement member names the hop that broke

de8837a stopped telling the author to qualify an object that resolved, but
reported the whole member tail against the object: a live claim on
`acme::shop::Order.reference.display`, with `reference` still present, read
"'acme::shop::Order' has no member 'reference.display'". It now walks the path
and names the first segment that does not resolve and the node it was looked
for under: "'acme::shop::Order.reference' has no member 'display'".

Co-Authored-By: Claude Opus 5 (1M context) <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01PFkf38KwqbtbAeVtizYBC7

Author: dmealing

CHANGELOG.md

@@ -52,7 +52,8 @@ edit (two registered `description` strings) and was ruled a hold, as 1.0.4's was
   Rename `dueDate` in the model and a live claim on `app::Task.dueDate` failed with
   `ERR_REQUIREMENT_DANGLING_REF`, then added *"An object named "Task" exists in: app::Task.
   Qualify it with its package (FQN)."* The ref was already qualified and the object resolved;
-  only the member was gone. The error now ends *"'app::Task' has no member 'dueDate'."* The
+  only the member was gone. The error now ends *"'app::Task' has no member 'dueDate'."*, and a
+  nested ref names the hop that broke (*"'app::Task.title' has no member 'display'."*). The
   did-you-mean hint still appears when the object itself does not resolve.
 
 ## [1.0.4] — 2026-09-14

server/typescript/packages/cli/src/lib/requirement-check.ts

@@ -131,6 +131,16 @@ export function splitMemberRef(ref: string): { owner: string; path: string[] } {
   return { owner: ref.slice(0, dot), path: ref.slice(dot + 1).split(".") };
 }
 
+/** Names the FIRST segment of a non-empty, unresolvable `path` under `obj`, and the node it
+ *  was looked for under: `acme::shop::Order.reference.display` with `reference` still present
+ *  reads "'acme::shop::Order.reference' has no member 'display'", not the whole tail. */
+function missingMemberHint(obj: MetaData, path: string[]): string {
+  let found = 0;
+  while (found < path.length - 1 && resolveMember(obj, path.slice(0, found + 1)) !== undefined) found++;
+  const parent = [obj.resolutionKey(), ...path.slice(0, found)].join(".");
+  return ` '${parent}' has no member '${path[found]}'.`;
+}
+
 /** Resolution keys of every root-level object whose `extends` chain reaches
  *  `ancestor`. Walks the RESOLVED super pointer rather than the raw string, so a
  *  cross-package or dotted reference resolves the same way the loader resolved
@@ -501,9 +511,7 @@ export function checkRequirements(root: MetaData, scan: RequirementScan = scanRe
           // The did-you-mean hint answers an OBJECT that failed to resolve. When the object
           // resolved and only the member is gone, it listed that same object back and said
           // to qualify it: name the member instead.
-          const hint = node === undefined
-            ? didYouMeanHint(root, owner)
-            : ` '${node.resolutionKey()}' has no member '${path.join(".")}'.`;
+          const hint = node === undefined ? didYouMeanHint(root, owner) : missingMemberHint(node, path);
           out.push({
             severity: "error", code: ERR_REQUIREMENT_DANGLING_REF, path: reqPath,
             message: `'${ref}' does not resolve in the loaded model (status '${String(req.status())}' — ` +

server/typescript/packages/cli/test/unit/requirement-check.test.ts

@@ -475,6 +475,25 @@ describe("requirement.* — reference resolution", () => {
     expect(dangling[0]!.message).toContain("'acme::shop::Order' has no member 'referenceCode'");
   });
 
+  test("a gone member under a member that DOES resolve names the first segment that failed", async () => {
+    // `reference` still exists; only `display` under it does not. Reporting the whole
+    // tail against the object ("'Order' has no member 'reference.display'") would not
+    // say which hop broke.
+    const r = await run(caps(COVER + `
+          - requirement.functional:
+              name: ReadableReference
+              level: 5
+              status: live
+              statement: "An order reference renders for a human"
+              counterexample: "A reference shown as a raw string"
+              implementedBy: ["acme::shop::Order.reference.display"]
+`), OTHER);
+    expect(r.loadError).toBeUndefined();
+    const dangling = r.diags.filter((x) => x.code === ERR_REQUIREMENT_DANGLING_REF);
+    expect(dangling.length).toBe(1);
+    expect(dangling[0]!.message).toContain("'acme::shop::Order.reference' has no member 'display'");
+  });
+
   test("splitMemberRef splits at the first dot after the package", () => {
     expect(splitMemberRef("acme::shop::Order")).toEqual({ owner: "acme::shop::Order", path: [] });
     expect(splitMemberRef("acme::shop::Order.total")).toEqual({