Make val loading order top-to-bottom

Fixes #2232

Within `build.sbt` this makes sure that definitions are ordered from top to bottom.
This matters when multiple subprojects refer to the same setting (probably not a good practice).

main-actions/src/main/scala/sbt/compiler/Eval.scala

@@ -161,8 +161,8 @@ final class Eval(
         case None    => ""
       }
     }
-    val i = evalCommon(definitions.map(_._1), imports, Some(""), ev)
-    new EvalDefinitions(i.loader, i.generated, i.enclosingModule, i.extra)
+    val i: EvalIntermediate[Seq[String]] = evalCommon(definitions.map(_._1), imports, Some(""), ev)
+    new EvalDefinitions(i.loader, i.generated, i.enclosingModule, i.extra.reverse)
   }
 
   private[this] def evalCommon[T](

sbt/src/sbt-test/project/val-order/build.sbt

@@ -0,0 +1,36 @@
+ThisBuild / scalaVersion     := "2.13.1"
+ThisBuild / version          := "0.1.0-SNAPSHOT"
+
+lazy val check = taskKey[Unit]("")
+lazy val intTask = taskKey[Int]("int task")
+
+lazy val root = (project in file("."))
+  .settings(
+    name := "val-ordering-test",
+    ThisBuild / organization := "root",
+    check := {
+      val o = (ThisBuild / organization).value
+      assert(o == "root.api.database.web", s"$o")
+      val x = (api / intTask).value
+      assert(x == 1, x.toString)
+
+    },
+  )
+
+lazy val api = project
+  .settings(
+    intTask := 0,
+    ThisBuild / organization := (ThisBuild / organization).value + ".api",
+  )
+
+lazy val database = project
+  .settings(
+    ThisBuild / organization := (ThisBuild / organization).value + ".database",
+  )
+
+lazy val web = project
+  .dependsOn(api, database)
+  .settings(
+    api / intTask := 1,
+    ThisBuild / organization := (ThisBuild / organization).value + ".web",
+  )

sbt/src/sbt-test/project/val-order/test

@@ -0,0 +1 @@
+> check