diff --git a/src/main/scala/sbt/DefaultProject.scala b/src/main/scala/sbt/DefaultProject.scala
index d0f9b9e93..b3873ff81 100644
--- a/src/main/scala/sbt/DefaultProject.scala
+++ b/src/main/scala/sbt/DefaultProject.scala
@@ -452,7 +452,7 @@ object BasicScalaProject
 	{
 		log.warn("No Main-Class attribute will be added automatically added:")
 		log.warn("Multiple classes with a main method were detected.  Specify main class explicitly with:")
-		log.warn("     override mainClass = Some(\"className\")")
+		log.warn("     override def mainClass = Some(\"className\")")
 	}
 }
 object BasicWebScalaProject
@@ -512,4 +512,4 @@ private object LibraryDependencies
 	private def isScalaLibraryJar(file: File) = isNamed(file)(ScalaLibraryPrefix)
 	private def isNamed(file: File)(name: String) = file.getName.startsWith(name)
 
-}
\ No newline at end of file
+}