case yn:
						// x is not a defined type and y is a defined type: select y.
						u.set(px, y)
					default:
						// Neither x nor y are defined types.
						if yc, _ := under(y).(*Chan); yc != nil && yc.dir != SendRecv {
							// y is a directed channel type: select y.
							u.set(px, y)
						}
					}
				}
				return true
			}
			return false
		}
		// otherwise, infer type from y
		u.set(px, y)

					case yn:
						// x is not a defined type and y is a defined type: select y.
						u.set(px, y)
					default:
						// Neither x nor y are defined types.
						if yc, _ := under(y).(*Chan); yc != nil && yc.dir != SendRecv {
							// y is a directed channel type: select y.
							u.set(px, y)
						}
					}
				}
				return true
			}
			return false
		}
		// otherwise, infer type from y
		u.set(px, y)