Fix cloneNode with typeAnnotation.

packages/babel-types/src/clone/cloneNode.js

@@ -37,6 +37,12 @@ export default function cloneNode<T: Object>(node: T, deep: boolean = true): T {
   // Special-case identifiers since they are the most cloned nodes.
   if (type === "Identifier") {
     newNode.name = node.name;
+
+    if (has(node, "typeAnnotation")) {
+      newNode.typeAnnotation = deep
+        ? cloneIfNodeOrArray(node.typeAnnotation, true)
+        : node.typeAnnotation;
+    }
   } else if (!has(NODE_FIELDS, type)) {
     throw new Error(`Unknown node type: "${type}"`);
   } else {

packages/babel-types/test/cloning.js

@@ -56,4 +56,20 @@ describe("cloneNode", function() {
     expect(node.object).toBe(cloned.object);
     expect(node.property).toBe(cloned.property);
   });
+
+  it("should preserve type annotations", function() {
+    const node = t.variableDeclaration("let", [
+      t.variableDeclarator({
+        ...t.identifier("value"),
+        typeAnnotation: t.anyTypeAnnotation(),
+      }),
+    ]);
+    const cloned = t.cloneNode(node, /* deep */ true);
+    expect(cloned.declarations[0].id.typeAnnotation).toEqual(
+      node.declarations[0].id.typeAnnotation,
+    );
+    expect(cloned.declarations[0].id.typeAnnotation).not.toBe(
+      node.declarations[0].id.typeAnnotation,
+    );
+  });
 });