LSP_Bad_post.swift

class RectangleField {

	var width: Float = 0
	var height: Float = 0

	var area: Float {
		return width * height
	}

}

class SquareField: RectangleField {

	override var area: Float {
		return width * width
	}

}

func printField(field: Field) {
	print(field.area)
}

let field = RectangleField()
field.width = 2
field.height = 4
printField(field: field) // 8

let squareField = SquareField()
squareField.width = 2
squareField.height = 4
printField(field: squareField) // 4