// various element types (named types)
	type (
		C1 chan int
		C1r <-chan int
		C1s chan<- int
		C2 chan float32
	)
	var (
		c1 C1
		c1r C1r
		c1s C1s
		c1a chan int
		c2 C2
	)
	_ = c1 == c1
	_ = c1 == c1r /* ERROR "mismatched types" */
	_ = c1 == c1s /* ERROR "mismatched types" */
	_ = c1r == c1s /* ERROR "mismatched types" */
	_ = c1 == c1a
	_ = c1a == c1