diff --git a/.github/workflows/ci.yml b/.github/workflows/ci.yml
index 0e28b571..32d3242f 100644
--- a/.github/workflows/ci.yml
+++ b/.github/workflows/ci.yml
@@ -55,7 +55,7 @@ jobs:
       fail-fast: false
       matrix:
         python-version: ["3.12"]
-        typedoc-version: ["0.25", "0.26"]
+        typedoc-version: ["0.25", "0.26", "0.27"]
 
     name: Python ${{ matrix.python-version}} + typedoc ${{ matrix.typedoc-version }}
     steps:
diff --git a/noxfile.py b/noxfile.py
index 2abf80a6..6d057f5a 100644
--- a/noxfile.py
+++ b/noxfile.py
@@ -26,7 +26,7 @@ def tests(session: Session) -> None:
 
 
 @nox.session(python=["3.12"])
-@nox.parametrize("typedoc", ["0.25", "0.26"])
+@nox.parametrize("typedoc", ["0.25", "0.26", "0.27"])
 def test_typedoc(session: Session, typedoc: str) -> None:
     # Install python dependencies
     session.install("-r", "requirements_dev.txt")
diff --git a/sphinx_js/js/convertType.ts b/sphinx_js/js/convertType.ts
index 3ad424c2..7f89c244 100644
--- a/sphinx_js/js/convertType.ts
+++ b/sphinx_js/js/convertType.ts
@@ -215,7 +215,10 @@ class TypeConverter implements TypeVisitor<Type> {
       // up so in this case we index on file name and reference name.
 
       // Another place where we incorrectly handle merged declarations
-      const src = refl.sources![0];
+      const src = type.reflection?.sources?.[0];
+      if (!src) {
+        return undefined;
+      }
       const newTarget = this.symbolToType.get(
         `${src.fullFileName}:${refl.name}`,
       );
@@ -299,18 +302,17 @@ class TypeConverter implements TypeVisitor<Type> {
   }
 
   reference(type: ReferenceType): Type {
+    // if we got a reflection use that. It's not all that clear how to deal
+    // with type arguments here though...
+    const res = this.convertPrivateReferenceToReflection(type);
+    if (res) {
+      return res;
+    }
     if (type.isIntentionallyBroken()) {
       // If it's intentionally broken, don't add an xref. It's probably a type
       // parameter.
       return this.addTypeArguments(type, [type.name]);
     } else {
-      // if we got a reflection use that. It's not all that clear how to deal
-      // with type arguments here though...
-      const res = this.convertPrivateReferenceToReflection(type);
-      // else use convertReferenceToXRef
-      if (res) {
-        return res;
-      }
       return this.convertReferenceToXRef(type);
     }
   }
diff --git a/tests/test.ts b/tests/test.ts
index 17c87769..407c0838 100644
--- a/tests/test.ts
+++ b/tests/test.ts
@@ -33,7 +33,7 @@ suite("types.ts", async () => {
   function getObject(name: string): TopLevelIR {
     const obj = map.get(name);
     assert(obj);
-    return obj!;
+    return obj;
   }
   suite("basic", async () => {
     for (const [obj_name, type_name] of [
@@ -100,4 +100,14 @@ suite("types.ts", async () => {
       },
     ]);
   });
+  await test("private_type_alias_1", () => {
+    const obj = getObject("typeIsPrivateTypeAlias1");
+    assert.strictEqual(obj.kind, "attribute");
+    assert.deepStrictEqual(joinType(obj.type), "{ a: number; b: string; }");
+  });
+  await test("private_type_alias_2", () => {
+    const obj = getObject("typeIsPrivateTypeAlias2");
+    assert.strictEqual(obj.kind, "attribute");
+    assert.deepStrictEqual(joinType(obj.type), "{ a: number; b: string; }");
+  });
 });