Merge pull request #2667 from OlegYch/fix-project-macro-error-message

Better error message from project macro

main/src/main/scala/sbt/Project.scala

@@ -617,7 +617,7 @@ object Project extends ProjectExtra {
   def projectMacroImpl(c: Context): c.Expr[Project] =
     {
       import c.universe._
-      val enclosingValName = std.KeyMacro.definingValName(c, methodName => s"""$methodName must be directly assigned to a val, such as `val x = $methodName`.""")
+      val enclosingValName = std.KeyMacro.definingValName(c, methodName => s"""$methodName must be directly assigned to a val, such as `val x = $methodName`. Alternatively, you can use `sbt.Project.apply`""")
       val name = c.Expr[String](Literal(Constant(enclosingValName)))
       reify { Project(name.splice, new File(name.splice)) }
     }