Fix test, add test to demonstrate how custom elements will work

types/react-test-renderer/react-test-renderer-tests.ts

@@ -43,14 +43,14 @@ function testInstance(inst: ReactTestInstance) {
     inst.props = {
         prop1: "p",
     };
-    inst.type = "t";
-    testInstance(inst.find(n => n.type === "t"));
+    inst.type = "a";
+    testInstance(inst.find(n => n.type === "a"));
     testInstance(inst.findByProps({ prop1: "p" }));
-    testInstance(inst.findByType("t"));
+    testInstance(inst.findByType("a"));
     testInstance(inst.findByType(TestComponent));
     inst.findAll(n => n.type === "t", { deep: true }).map(testInstance);
     inst.findAllByProps({ prop1: "p" }, { deep: true }).map(testInstance);
-    inst.findAllByType("t", { deep: true }).map(testInstance);
+    inst.findAllByType("a", { deep: true }).map(testInstance);
     inst.findAllByType(TestComponent, { deep: true }).map(testInstance);
 }
 

types/react/test/tsx.tsx

@@ -332,3 +332,16 @@ const HasFoo2: React.ReactType<{ foo: boolean }> = (props: { foo: boolean }) =>
 const HasFoo3: React.ReactType<{ foo: boolean }> = (props: { foo: string }) => null; // $ExpectError
 const HasHref: React.ReactType<{ href?: string }> = 'a';
 const HasHref2: React.ReactType<{ href?: string }> = 'div'; // $ExpectError
+
+const CustomElement: React.ReactType = 'my-undeclared-element'; // $ExpectError
+
+// custom elements now need to be declared as intrinsic elements
+declare global {
+    namespace JSX {
+        interface IntrinsicElements {
+            'my-declared-element': {};
+        }
+    }
+}
+
+const CustomElement2: React.ReactType = 'my-declared-element';