fix(core/webidl): give unique IDs to partial namespace blocks

src/core/webidl.js

@@ -236,7 +236,8 @@ function resolveNameAndId(defn, parent) {
     case "callback interface":
     case "dictionary":
     case "interface":
-    case "interface mixin": {
+    case "interface mixin":
+    case "namespace": {
       idlId += resolvePartial(defn);
       break;
     }

tests/spec/core/webidl-spec.js

@@ -1791,6 +1791,30 @@ callback CallBack = Z? (X x, optional Y y, /*trivia*/ optional Z z);
     expect(errors[0].details).toContain("Promise<void>");
   });
 
+  it("gives unique IDs to partial namespaces", async () => {
+    const body = `
+      <section>
+        <pre class="idl">
+          namespace Foo { undefined bar(); };
+          partial namespace Foo { undefined baz(); };
+          partial namespace Foo { undefined qux(); };
+        </pre>
+      </section>
+    `;
+    const ops = makeStandardOps(null, body);
+    const doc = await makeRSDoc(ops);
+    const idls = [
+      ...doc.querySelectorAll("pre.idl code [data-idl][id]"),
+    ].filter(el => /^idl-def-foo(?:-partial-[12])?$/.test(el.id));
+    expect(idls).toHaveSize(3);
+    const ids = idls.map(el => el.id);
+    const uniqueIds = new Set(ids);
+    expect(uniqueIds.size).toBe(ids.length);
+    expect(ids).toContain("idl-def-foo");
+    expect(ids).toContain("idl-def-foo-partial-1");
+    expect(ids).toContain("idl-def-foo-partial-2");
+  });
+
   it("does not set data-dfn-for on top-level IDL entities inside a data-dfn-for section (prose dfns)", () => {
     const section = doc.querySelector("#top-level-no-dfn-for");
     const dictDfn = section.querySelector("dfn[data-dfn-type='dictionary']");