Highlighting ??? as an error

In Predef.scala, ??? throws a NotImplementedException and returns
Nothing, making it a useful placeholder for development.

Author: Andrew Laucius

syntax/scala.vim

@@ -58,6 +58,9 @@ syn match scalaInstanceHash /#/ contained nextgroup=scalaInstanceDeclaration
 hi link scalaInstanceDeclaration Special
 hi link scalaInstanceHash Type
 
+syn match scalaUnimplemented /???/
+hi link scalaUnimplemented ERROR
+
 syn match scalaCapitalWord /\<[A-Z][A-Za-z0-9$]*\>/
 hi link scalaCapitalWord Special
 

syntax/testfile.scala

@@ -71,6 +71,8 @@ class ScalaClass(i: Int = 12, b: Trait[A, Trait[B, C]]) extends B with SomeTrait
     where id = $id and name = ${s"$name Jr"} and age > ${age + 10}
   """
 
+  val notImplemented = ???
+
   implicit val somethingImplicit = true
 
   // Ripped off from Scalaz