pointers: compose nested yields renames

packages/pointers/CHANGELOG.md

@@ -6,6 +6,12 @@ itself are tracked in the root [`CHANGELOG.md`](../../CHANGELOG.md).
 
 ## Unreleased
 
+### Fixed
+
+- `dereference` composes the `yields` renames of nested template references.
+  A region now takes the rename of each enclosing reference, innermost first,
+  where only the innermost rename used to apply.
+
 ## 0.1.0-preview.0 — 2026-09-21
 
 The version scheme changed: prerelease versions are now `preview.<n>`, and

packages/pointers/src/dereference/generate.ts

@@ -60,12 +60,15 @@ export async function* generateRegions(
         while (!result.done) {
           let region = result.value;
 
-          // Apply rename if in context and region has a name in mapping
-          const currentMapping = renameStack[renameStack.length - 1];
-          if (currentMapping && region.name) {
-            const newName = currentMapping[region.name];
-            if (newName && newName !== region.name) {
-              region = { ...region, name: newName };
+          // Apply every active rename, innermost template first, so that
+          // nested yields compose
+          if (region.name) {
+            const name = renameStack.reduceRight(
+              (name, mapping) => mapping[name] ?? name,
+              region.name,
+            );
+            if (name !== region.name) {
+              region = { ...region, name };
             }
           }
 

packages/pointers/src/dereference/index.test.ts

@@ -537,6 +537,36 @@ describe("dereference", () => {
     expect(regions.named("outer-data")).toHaveLength(2);
   });
 
+  it("composes yields renames across nested template references", async () => {
+    const templates: Pointer.Templates = {
+      leaf: {
+        expect: ["slot"],
+        for: { name: "data", location: "storage", slot: "slot" },
+      },
+      middle: {
+        expect: ["slot"],
+        for: {
+          template: "leaf",
+          yields: { data: "name-data" },
+        },
+      },
+    };
+
+    const pointer: Pointer = {
+      define: { slot: 10 },
+      in: {
+        template: "middle",
+        yields: { "name-data": "value-name-data" },
+      },
+    };
+
+    const cursor = await dereference(pointer, { templates });
+    const { regions } = await cursor.view(state);
+
+    expect(regions).toHaveLength(1);
+    expect(regions[0].name).toEqual("value-name-data");
+  });
+
   it("works for inline template definitions", async () => {
     const pointer: Pointer = {
       templates: {