Always eta-expand AppliedTypeTrees arguments

This makes compileIndexedSeq pass again.

Author: smarter

src/dotty/tools/dotc/typer/Typer.scala

@@ -882,7 +882,7 @@ class Typer extends Namer with TypeAssigner with Applications with Implicits wit
           else
             (arg, WildcardType)
         val arg1 = typed(desugaredArg, argPt)
-        adaptTypeArg(arg1, if (tparam.isCompleted) tparam.info else WildcardType)
+        adaptTypeArg(arg1, tparam.info)
       }
       val args1 = args.zipWithConserve(tparams)(typedArg(_, _)).asInstanceOf[List[Tree]]
       // check that arguments conform to bounds is done in phase PostTyper

test/dotc/tests.scala

@@ -193,7 +193,7 @@ class tests extends CompilerTest {
         |./scala-scala/src/library/scala/collection/GenSeqLike.scala
         |./scala-scala/src/library/scala/collection/SeqLike.scala
         |./scala-scala/src/library/scala/collection/generic/GenSeqFactory.scala""".stripMargin)
-  // @Test def compileIndexedSeq = compileLine("./scala-scala/src/library/scala/collection/immutable/IndexedSeq.scala")
+  @Test def compileIndexedSeq = compileLine("./scala-scala/src/library/scala/collection/immutable/IndexedSeq.scala")
 
   @Test def dotty = compileDir(dottyDir, ".", List("-deep", "-Ycheck-reentrant"))(allowDeepSubtypes) // note the -deep argument