[FIR] Add ability to generate members and nested classifiers for generated classes

core/compiler.common/src/org/jetbrains/kotlin/name/ClassId.java

@@ -20,6 +20,8 @@ import kotlin.text.StringsKt;
 import org.jetbrains.annotations.NotNull;
 import org.jetbrains.annotations.Nullable;
 
+import java.util.List;
+
 /**
  * A class name which is used to uniquely identify a Kotlin class.
  *
@@ -61,6 +63,12 @@ public final class ClassId {
         return relativeClassName;
     }
 
+    @Nullable
+    public ClassId getParentClassId() {
+        if (!isNestedClass()) return null;
+        return new ClassId(packageFqName, relativeClassName.parent(), isLocal());
+    }
+
     @NotNull
     public Name getShortClassName() {
         return relativeClassName.shortName();