Why do I need to write parameter names

functions.go

func main() {
	ebiten.SetWindowSize(1280, 640)
	ebiten.SetWindowTitle("Wordy")
	if err := ebiten.RunGame(&wordy.Game{}); err != nil {
		panic(err)
	}
}

func (g *Game) Layout(outsideWidth int, outSideHeight int) (screenWidth int, screenHeight int) {
	return ScreenWidth, ScreenHeight
}

// I have to keep outsideWidth and outSideHeight parameters
// Otherwise, GoLand shows an error
// Why