A quick Scala gotcha

Wouldn't it be nice, I thought, to be able to put UI decoration as a mixin to any sort of component, like

	trait HasImage {
	def image : java.awt.Image
	}
	trait Tiled {
	self : scala.swing.Component with HasImage =>
	peer.setOpaque(false)
	override def paintComponent(g :Graphics2D) {
	for(x <- 0.until(peer.getWidth(), image.getWidth(peer));
	y <- 0.until(peer.getHeight(), image.getHeight(peer)))
	{
	g.drawImage(image, x, y, peer);
	}
	self.paintComponent(g)
	}
	}
	class TiledContainer(tiledBackgroundImage : Image, constraints :Seq[String]) extends Form(constraints) with Tiled with HasImage {
	val image = tiledBackgroundImage
	}

view raw gistfile1.scala hosted with ❤ by GitHub

In Scala 2.8 recent nightlies, this compiles happily -- but when you run it, the self.paintComponent(g) call just stack overflows, flipping between TiledContainer.paintComponent and Tiled.paintComponent as it goes.

At 2.7.x, it doesn't compile -- which at least prevents you getting the run-time error

error: overriding method paintComponent in class Component of type
(g: scala.swing.package.Graphics2D)Unit; method paintComponent in trait Tiled of type
(g: java.awt.Graphics2D)Unit cannot override a concrete member without a third member 
that's overridden by both (this rule is designed to prevent ``accidental overrides'')
class TiledContainer(tiledBackgroundImage : Image, constraints :Seq[String]) extends 
Form(constraints) with Tiled with HasImage {