Don't emit inner classes as static classes

compiler/src/dotty/tools/backend/jvm/BackendInterface.scala

@@ -583,8 +583,8 @@ abstract class BackendInterface extends BackendInterfaceDefinitions {
      *   object T { def f { object U } }
      * the owner of U is T, so UModuleClass.isStatic is true. Phase travel does not help here.
      */
-    def isOriginallyStaticOwner: Boolean
-
+    def isOriginallyStaticOwner: Boolean =
+      isPackageClass || isModuleClass && originalOwner.isOriginallyStaticOwner
 
     def samMethod(): Symbol
 

compiler/src/dotty/tools/backend/jvm/DottyBackendInterface.scala

@@ -839,18 +839,6 @@ class DottyBackendInterface(outputDirectory: AbstractFile, val superCallsMap: Ma
         toDenot(sym).owner.is(Flags.PackageClass)
       }
 
-    /**
-     * This is basically a re-implementation of sym.isStaticOwner, but using the originalOwner chain.
-     *
-     * The problem is that we are interested in a source-level property. Various phases changed the
-     * symbol's properties in the meantime, mostly lambdalift modified (destructively) the owner.
-     * Therefore, `sym.isStatic` is not what we want. For example, in
-     *   object T { def f { object U } }
-     * the owner of U is T, so UModuleClass.isStatic is true. Phase travel does not help here.
-     */
-    def isOriginallyStaticOwner: Boolean = sym.isStatic
-
-
     def addRemoteRemoteExceptionAnnotation: Unit = ()
 
     def samMethod(): Symbol =

compiler/test/dotc/run-test-pickling.blacklist

@@ -15,3 +15,4 @@ instances.scala
 instances-anonymous.scala
 mixin-forwarder-overload
 t8905
+t10889

tests/run/t10889.check

@@ -0,0 +1 @@
+new O(o).I[](i)

tests/run/t10889/O.scala

@@ -0,0 +1,6 @@
+package p
+class O(val o: String) {
+  class I[T](val i: String) {
+    println(s"new O($o).I[]($i)")
+  }
+}

tests/run/t10889/Test.java

@@ -0,0 +1,6 @@
+public class Test {
+  public static void main(String[] args) {
+    p.O l = new p.O("o");
+    p.O.I<Object> s = l.new I<Object>(/*l,*/ "i");
+  }
+}