test: add Bundle<T> propagation unit test and fix no-predicate demo

Author: ryukzak

examples/typescript-r4/resource.test.ts

@@ -135,10 +135,10 @@ test("Bundle<T> narrows entry resources without type predicates", () => {
         ],
     };
 
-    // Discriminated-union narrowing works without a `r is Observation` predicate
+    // TS 5.5+ infers the type predicate from the discriminated union — no explicit `r is Observation` needed
     const observations: Observation[] = (bundle.entry ?? [])
         .map((e) => e.resource)
-        .filter((r): r is Observation => r?.resourceType === "Observation");
+        .filter((r) => r?.resourceType === "Observation");
 
     expect(observations).toHaveLength(1);
     expect(observations[0]!.id).toBe("glucose-obs-1");

test/api/write-generator/typescript.test.ts

@@ -30,6 +30,11 @@ describe("TypeScript Writer Generator", async () => {
         expect(bundleTs).toContain("export interface BundleEntry<T extends Resource = Resource>");
         expect(bundleTs).toContain("resource?: T");
     });
+    it("generates Bundle with generic entry type (nested generic propagation)", async () => {
+        const bundleTs = files["generated/types/hl7-fhir-r4-core/Bundle.ts"];
+        expect(bundleTs).toContain("export interface Bundle<T extends Resource = Resource>");
+        expect(bundleTs).toContain("entry?: BundleEntry<T>[]");
+    });
     it("generates BundleEntryResponse with generic type-family parameter", async () => {
         const bundleTs = files["generated/types/hl7-fhir-r4-core/Bundle.ts"];
         expect(bundleTs).toContain("export interface BundleEntryResponse<T extends Resource = Resource>");