improvement: sort abstract members for auto implement

[Cherry-picked d31aab8]

Author: kasiaMarek

presentation-compiler/src/main/dotty/tools/pc/completions/OverrideCompletions.scala

@@ -279,7 +279,14 @@ object OverrideCompletions:
         else ""
       (indent, indent, lastIndent)
     end calcIndent
-    val abstractMembers = defn.typeOpt.abstractTermMembers.map(_.symbol)
+    val abstractMembers =
+      defn.tpe.abstractTermMembers.map(_.symbol).groupBy(_.owner).map {
+        case (owner, members) => (owner, members.sortWith{ (sym1, sym2) =>
+          if(sym1.sourcePos.exists && sym2.sourcePos.exists)
+            sym1.sourcePos.start <= sym2.sourcePos.start
+          else !sym2.sourcePos.exists
+        })
+      }.toSeq.sortBy(_._1.name.decoded).flatMap(_._2)
 
     val caseClassOwners = Set("Product", "Equals")
     val overridables =

presentation-compiler/test/dotty/tools/pc/tests/edit/AutoImplementAbstractMembersSuite.scala

@@ -345,10 +345,10 @@ class AutoImplementAbstractMembersSuite extends BaseCodeActionSuite:
          |object Main {
          |  class Baz extends Bar {
          |
-         |    override def foo: Int = ???
-         |
          |    override def bar: Int = ???
          |
+         |    override def foo: Int = ???
+         |
          |  }
          |}
          |""".stripMargin
@@ -1288,10 +1288,10 @@ class AutoImplementAbstractMembersSuite extends BaseCodeActionSuite:
          |
          |case class Concrete() extends Base:
          |
-         |  override def bar(x: String): String = ???
-         |
          |  override def foo(x: Int): Int = ???
          |
+         |  override def bar(x: String): String = ???
+         |
          |  def aaa = "aaa"
          |end Concrete
          |""".stripMargin