function checkUnion( val, section ) {
		var correction;
		var elem;
		var i;
		for ( i = 0; i < val.elements.length; i++ ) {
			elem = val.elements[ i ];
			if ( elem.name ) {
				correction = correctTypedef( elem.name );
				if ( correction ) {
					context.report( '"'+elem.name+'" type definition should be "'+correction+'"', section );
				}
			}
		}
	}
Checks the type definitions of a union definition such as `(string|null)` for typos.

@private
@param {Object} val - union definition
@param {Object} section - function documentation section