Fix for KT-10881 Declaring constant in a mutlifile class causes an IllegalAccessError on its usage.

Generate fields for 'const' properties in facade class.

NB reading annotations for 'const' vals in multifile class doesn't work, KT-10892.

compiler/backend/src/org/jetbrains/kotlin/codegen/PropertyCodegen.java

@@ -114,7 +114,7 @@ public class PropertyCodegen {
         assert kind == OwnerKind.PACKAGE || kind == OwnerKind.IMPLEMENTATION || kind == OwnerKind.DEFAULT_IMPLS
                 : "Generating property with a wrong kind (" + kind + "): " + descriptor;
 
-        if (CodegenContextUtil.isImplClassOwner(context)) {
+        if (isBackingFieldOwner(descriptor)) {
             assert declaration != null : "Declaration is null for different context: " + context;
 
             genBackingFieldAndAnnotations(declaration, descriptor, false);
@@ -128,6 +128,13 @@ public class PropertyCodegen {
         }
     }
 
+    private boolean isBackingFieldOwner(@NotNull PropertyDescriptor descriptor) {
+        if (descriptor.isConst()) {
+            return !(context instanceof MultifileClassPartContext);
+        }
+        return CodegenContextUtil.isImplClassOwner(context);
+    }
+
     private void genBackingFieldAndAnnotations(@NotNull KtNamedDeclaration declaration, @NotNull PropertyDescriptor descriptor, boolean isParameter) {
         boolean hasBackingField = hasBackingField(declaration, descriptor);
         boolean hasDelegate = declaration instanceof KtProperty && ((KtProperty) declaration).hasDelegate();

compiler/backend/src/org/jetbrains/kotlin/codegen/state/JetTypeMapper.java

@@ -159,7 +159,7 @@ public class JetTypeMapper {
         if (file != null) {
             Visibility visibility = descriptor.getVisibility();
             if (!publicFacade ||
-                descriptor instanceof PropertyDescriptor ||
+                isNonConstProperty(descriptor) ||
                 Visibilities.isPrivate(visibility) ||
                 isAccessor/*Cause of KT-9603*/
             ) {
@@ -181,6 +181,12 @@ public class JetTypeMapper {
                                    " in package fragment " + descriptor.getContainingDeclaration());
     }
 
+    private static boolean isNonConstProperty(@NotNull CallableMemberDescriptor descriptor) {
+        if (!(descriptor instanceof PropertyDescriptor)) return false;
+        PropertyDescriptor propertyDescriptor = (PropertyDescriptor) descriptor;
+        return !propertyDescriptor.isConst();
+    }
+
     public static class ContainingClassesInfo {
         private final ClassId facadeClassId;
         private final ClassId implClassId;