Redundant visibility modifier: do not report for 'internal' inside 'private'

#KT-35639 Fixed

idea/src/org/jetbrains/kotlin/idea/inspections/RedundantVisibilityModifierInspection.kt

@@ -25,6 +25,7 @@ import org.jetbrains.kotlin.psi.KtProperty
 import org.jetbrains.kotlin.psi.KtPropertyAccessor
 import org.jetbrains.kotlin.psi.declarationVisitor
 import org.jetbrains.kotlin.psi.psiUtil.containingClassOrObject
+import org.jetbrains.kotlin.psi.psiUtil.isPrivate
 import org.jetbrains.kotlin.psi.psiUtil.visibilityModifier
 import org.jetbrains.kotlin.utils.addToStdlib.firstNotNullResult
 import org.jetbrains.kotlin.resolve.descriptorUtil.isEffectivelyPublicApi
@@ -42,7 +43,9 @@ class RedundantVisibilityModifierInspection : AbstractKotlinInspection(), Cleanu
             val redundantVisibility = when {
                 visibilityModifier.node.elementType == implicitVisibility ->
                     implicitVisibility
-                declaration.hasModifier(KtTokens.INTERNAL_KEYWORD) && declaration.containingClassOrObject?.isLocal == true ->
+                declaration.hasModifier(KtTokens.INTERNAL_KEYWORD) && declaration.containingClassOrObject?.let {
+                    it.isLocal || it.isPrivate()
+                } == true ->
                     KtTokens.INTERNAL_KEYWORD
                 else ->
                     null

idea/testData/inspectionsLocal/redundantVisibilityModifier/internalInPrivateClass.kt

@@ -0,0 +1,3 @@
+private class Foo {
+    <caret>internal fun bar() {}
+}

idea/testData/inspectionsLocal/redundantVisibilityModifier/internalInPrivateClass.kt.after

@@ -0,0 +1,3 @@
+private class Foo {
+    fun bar() {}
+}

idea/tests/org/jetbrains/kotlin/idea/inspections/LocalInspectionTestGenerated.java

@@ -8046,6 +8046,11 @@ public class LocalInspectionTestGenerated extends AbstractLocalInspectionTest {
             KotlinTestUtils.assertAllTestsPresentByMetadataWithExcluded(this.getClass(), new File("idea/testData/inspectionsLocal/redundantVisibilityModifier"), Pattern.compile("^([\\w\\-_]+)\\.(kt|kts)$"), null, true);
         }
 
+        @TestMetadata("internalInPrivateClass.kt")
+        public void testInternalInPrivateClass() throws Exception {
+            runTest("idea/testData/inspectionsLocal/redundantVisibilityModifier/internalInPrivateClass.kt");
+        }
+
         @TestMetadata("overridePropertySetter.kt")
         public void testOverridePropertySetter() throws Exception {
             runTest("idea/testData/inspectionsLocal/redundantVisibilityModifier/overridePropertySetter.kt");