Fix #1786: support use package object as value

Author: liufengyun

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

@@ -357,6 +357,9 @@ class Typer extends Namer with TypeAssigner with Applications with Implicits wit
       }
 
     val tree1 = ownType match {
+      case ownType: NamedType if ownType.symbol.is(Package) && !pt.isInstanceOf[SelectionProto] =>
+        val pkgObj = ownType.symbol.moduleClass.denot.asInstanceOf[PackageClassDenotation].packageObj
+        if (pkgObj.exists) ref(pkgObj.valRef) else tree.withType(ownType)
       case ownType: NamedType if !prefixIsElidable(ownType) =>
         ref(ownType).withPos(tree.pos)
       case _ =>

tests/pos/i1786.scala

@@ -0,0 +1,11 @@
+package object meta {
+  def apply(x: Int): Int = x * x
+}
+
+class Test {
+  def f = meta {
+    5 + 4
+  }
+
+  meta
+}