// @target: es2015
//@filename: file.tsx
//@jsx: preserve
declare namespace JSX {
	interface Element { }
	interface IntrinsicElements {
		test1: { "data-foo"?: string };
		test2: { "data-foo"?: string };
	}
}

// Invalid names
<test1 32data={32} />;
<test2 -data={32} />;