SI-5720: Qual block doesn't update sym owner

A one-line change to blockWithQualifier. The symptom is
undefined tmp var symbols in the backend; lamba lift thinks
the tmp var is free and adds it to anonfun ctors.

src/compiler/scala/tools/nsc/typechecker/NamesDefaults.scala

@@ -155,6 +155,8 @@ trait NamesDefaults { self: Analyzer =>
         val sym = blockTyper.context.owner.newValue(unit.freshTermName("qual$"), qual.pos) setInfo qual.tpe
         blockTyper.context.scope enter sym
         val vd = atPos(sym.pos)(ValDef(sym, qual) setType NoType)
+        // it stays in Vegas: SI-5720, SI-5727
+        qual changeOwner (blockTyper.context.owner -> sym)
 
         var baseFunTransformed = atPos(baseFun.pos.makeTransparent) {
           // don't use treeCopy: it would assign opaque position.

test/files/pos/t5720-ownerous.scala

@@ -0,0 +1,56 @@
+
+/*
+ * The block under qual$1 must be owned by it.
+ * In the sample bug, the first default arg generates x$4,
+ * the second default arg generates qual$1, hence the maximal
+ * minimization.
+ *
+    <method> <triedcooking> def model: C.this.M = {
+      val qual$1: C.this.M = scala.Option.apply[C.this.M]({
+  val x$1: lang.this.String("foo") = "foo";
+  val x$2: String = C.this.M.apply$default$2("foo");
+  C.this.M.apply("foo")(x$2)
+}).getOrElse[C.this.M]({
+        val x$3: lang.this.String("bar") = "bar";
+        val x$4: String = C.this.M.apply$default$2("bar");
+        C.this.M.apply("bar")(x$4)
+      });
+      val x$5: lang.this.String("baz") = "baz";
+      val x$6: String = qual$1.copy$default$2("baz");
+      qual$1.copy("baz")(x$6)
+    }
+ */
+class C {
+  case class M(currentUser: String = "anon")(val message: String = "empty")
+  val m = M("foo")()
+
+  // reported
+  //def model = Option(M("foo")()).getOrElse(M("bar")()).copy(currentUser = "")()
+
+  // the bug
+  def model = Option(m).getOrElse(M("bar")()).copy("baz")()
+
+  // style points for this version
+  def modish = ((null: Option[M]) getOrElse new M()()).copy()()
+
+  // various simplifications are too simple
+  case class N(currentUser: String = "anon")
+  val n = N("fun")
+  def nudel = Option(n).getOrElse(N()).copy()
+}
+
+object Test {
+  def main(args: Array[String]) {
+    val c = new C
+    println(c.model.currentUser)
+    println(c.model.message)
+  }
+}
+/*
+symbol value x$4$1 does not exist in badcopy.C.model
+at scala.reflect.internal.SymbolTable.abort(SymbolTable.scala:45)
+at scala.tools.nsc.Global.abort(Global.scala:202)
+at scala.tools.nsc.backend.icode.GenICode$ICodePhase.liftedTree2$1(GenICode.scala:998)
+at scala.tools.nsc.backend.icode.GenICode$ICodePhase.scala$tools$nsc$backend$icode$GenICode$ICodePhase$$genLoad(GenICode.scala:992)
+*/
+

test/files/pos/t5727.scala

@@ -0,0 +1,31 @@
+
+/*
+ * We like operators, bar none.
+ */
+object Test {
+
+  trait SomeInfo
+  case object NoInfo extends SomeInfo
+
+  sealed abstract class Res[+T]
+  case object NotRes extends Res[Nothing]
+
+
+  abstract class Base[+T] {
+    def apply(f: String): Res[T]
+    // 'i' crashes the compiler, similarly if we use currying
+    //def |[U >: T](a: => Base[U], i: SomeInfo = NoInfo): Base[U] = null
+    def bar[U >: T](a: => Base[U], i: SomeInfo = NoInfo): Base[U] = null
+  }
+
+  implicit def fromStringToBase(a: String): Base[String] = new Base[String] { def apply(in: String) = NotRes }
+
+  // bug
+  //def Sample: Base[Any] = ( rep("foo" | "bar") | "sth")
+  def Sample: Base[Any] = ( rep("foo" bar "bar") bar "sth")
+
+  def rep[T](p: => Base[T]): Base[T] = null // whatever
+
+  def main(args: Array[String]) {
+  }
+}