Allow FutureDefs in changeOwner

Without it, the previous commit make LazyVals blow up wgen compiling dotc/transform. I could not fugure out why, but here is the stacktrace I saw.

dotty.tools.dotc.core.Denotations$NotDefinedHere: demanding denotation of method $anonfun at phase seqLiterals(17) outside defined interval: defined periods are Period(22..22, run = 2)
	at dotty.tools.dotc.core.Denotations$SingleDenotation.current(Denotations.scala:598)
	at dotty.tools.dotc.core.Types$NamedType.computeDenot(Types.scala:1221)
	at dotty.tools.dotc.core.Types$NamedType.denotAt(Types.scala:1206)
	at dotty.tools.dotc.core.Types$NamedType.denot(Types.scala:1194)
	at dotty.tools.dotc.ast.Trees$DenotingTree.denot(Trees.scala:270)
	at dotty.tools.dotc.ast.Trees$Tree.symbol(Trees.scala:187)
	at dotty.tools.dotc.ast.TypedTreeInfo$$anonfun$localSyms$1.apply(TreeInfo.scala:437)
	at dotty.tools.dotc.ast.TypedTreeInfo$$anonfun$localSyms$1.apply(TreeInfo.scala:437)
	at scala.collection.TraversableLike$WithFilter$$anonfun$map$2.apply(TraversableLike.scala:728)
	at scala.collection.immutable.List.foreach(List.scala:381)
	at scala.collection.TraversableLike$WithFilter.map(TraversableLike.scala:727)
	at dotty.tools.dotc.ast.TypedTreeInfo$class.localSyms(TreeInfo.scala:437)
	at dotty.tools.dotc.ast.tpd$.localSyms(tpd.scala:19)
	at dotty.tools.dotc.ast.TreeTypeMap.transformDefs(TreeTypeMap.scala:116)
	at dotty.tools.dotc.ast.TreeTypeMap.transform(TreeTypeMap.scala:98)
	at dotty.tools.dotc.ast.Trees$Instance$TreeMap$$anonfun$transform$2.apply(Trees.scala:1181)
	at dotty.tools.dotc.ast.Trees$Instance$TreeMap$$anonfun$transform$2.apply(Trees.scala:1181)
	at scala.collection.immutable.List.loop$1(List.scala:172)
	at scala.collection.immutable.List.mapConserve(List.scala:188)
	at dotty.tools.dotc.ast.Trees$Instance$TreeMap.transform(Trees.scala:1181)
	at dotty.tools.dotc.ast.Trees$Instance$TreeMap.transform(Trees.scala:1100)
	at dotty.tools.dotc.ast.TreeTypeMap.transform(TreeTypeMap.scala:108)
	at dotty.tools.dotc.ast.Trees$Instance$TreeMap$$anonfun$transform$2.apply(Trees.scala:1181)
	at dotty.tools.dotc.ast.Trees$Instance$TreeMap$$anonfun$transform$2.apply(Trees.scala:1181)
	at scala.collection.immutable.List.loop$1(List.scala:172)
	at scala.collection.immutable.List.mapConserve(List.scala:188)
	at dotty.tools.dotc.ast.Trees$Instance$TreeMap.transform(Trees.scala:1181)
	at dotty.tools.dotc.ast.Trees$Instance$TreeMap.transform(Trees.scala:1100)
	at dotty.tools.dotc.ast.TreeTypeMap.transform(TreeTypeMap.scala:108)
	at dotty.tools.dotc.ast.Trees$Instance$TreeMap.transform(Trees.scala:1100)
	at dotty.tools.dotc.ast.TreeTypeMap.transform(TreeTypeMap.scala:108)
	at dotty.tools.dotc.ast.Trees$Instance$TreeMap.transform(Trees.scala:1094)
	at dotty.tools.dotc.ast.TreeTypeMap.transform(TreeTypeMap.scala:108)
	at dotty.tools.dotc.ast.Trees$Instance$TreeMap.transform(Trees.scala:1100)
	at dotty.tools.dotc.ast.TreeTypeMap.transform(TreeTypeMap.scala:108)
	at dotty.tools.dotc.ast.TreeTypeMap.apply(TreeTypeMap.scala:129)
	at dotty.tools.dotc.ast.tpd$TreeOps$.loop$1(tpd.scala:565)
	at dotty.tools.dotc.ast.tpd$TreeOps$.changeOwner$extension(tpd.scala:568)
	at dotty.tools.dotc.transform.LazyVals.transformLocalValDef(LazyVals.scala:110)
	at dotty.tools.dotc.transform.LazyVals.transformValDef(LazyVals.scala:64)

Author: odersky

src/dotty/tools/dotc/ast/tpd.scala

@@ -563,7 +563,7 @@ object tpd extends Trees.Instance[Type] with TypedTreeInfo {
           loop(from.owner, from :: froms, to :: tos)
         else {
           //println(i"change owner ${from :: froms}%, % ==> $tos of $tree")
-          new TreeTypeMap(oldOwners = from :: froms, newOwners = tos).apply(tree)
+          new TreeTypeMap(oldOwners = from :: froms, newOwners = tos)(ctx.withMode(Mode.FutureDefsOK)).apply(tree)
         }
       }
       loop(from, Nil, to :: Nil)