pinescript 中显示错误，它说“输入‘shape1’时没有可行的替代方案

Question

pine 脚本中显示错误，它说“输入‘shape1’时没有可行的选择”下面是错误所在的语法。

// Plot Shapes for Breakout Signals
var shape1 = shape.none, shape2 = shape.none
if (hull1 > res1)
    shape1 := shape.triangleup
if (hull2 < supp2)
    shape2 := shape.triangledown
plotshape(hull1 > res1, title="High HMA Breakout Signal", text="Up", location=location.belowbar,
          color=green, textcolor=white, style=shape1, size=size.small)
plotshape(hull2 < supp2, title="Low HMA Breakout Signal", text="Down", location=location.abovebar,
          color=red, textcolor=white, style=shape2, size=size.small)