Do not suggest "add inner" quick fix for interfaces etc. #KT-18396 Fixed

idea/src/org/jetbrains/kotlin/idea/quickfix/AddModifierFix.kt

@@ -115,6 +115,16 @@ open class AddModifierFix(
                     if (parentClassOrObject is KtEnumEntry) return null
                 }
             }
+            if (modifier == INNER_KEYWORD) {
+                if (modifierListOwner is KtObjectDeclaration) return null
+                if (modifierListOwner is KtClass) {
+                    if (modifierListOwner.isInterface() ||
+                        modifierListOwner.isSealed() ||
+                        modifierListOwner.isEnum() ||
+                        modifierListOwner.isData() ||
+                        modifierListOwner.isAnnotation()) return null
+                }
+            }
             return AddModifierFix(modifierListOwner, modifier)
         }
 

idea/testData/quickfix/modifiers/nestedAbstractClass.kt

@@ -0,0 +1,6 @@
+// "Add 'inner' modifier" "true"
+class A() {
+    inner class B() {
+        abstract class <caret>C
+    }
+}

idea/testData/quickfix/modifiers/nestedAbstractClass.kt.after

@@ -0,0 +1,6 @@
+// "Add 'inner' modifier" "true"
+class A() {
+    inner class B() {
+        abstract inner class C
+    }
+}

idea/testData/quickfix/modifiers/nestedAnnotationClass.kt

@@ -0,0 +1,7 @@
+// "Add 'inner' modifier" "false"
+// ERROR: Annotation class is not allowed here
+class A() {
+    inner class B() {
+        annotation class <caret>C
+    }
+}

idea/testData/quickfix/modifiers/nestedDataClass.kt

@@ -0,0 +1,9 @@
+// "Add 'inner' modifier" "false"
+// ACTION: Create test
+// ERROR: Class is not allowed here
+// ERROR: Data class must have at least one primary constructor parameter
+class A() {
+    inner class B() {
+        data class <caret>C
+    }
+}

idea/testData/quickfix/modifiers/nestedEnumClass.kt

@@ -0,0 +1,9 @@
+// "Add 'inner' modifier" "false"
+// ACTION: Convert to sealed class
+// ACTION: Create test
+// ERROR: Enum class is not allowed here
+class A() {
+    inner class B() {
+        enum class <caret>C
+    }
+}

idea/testData/quickfix/modifiers/nestedInterface.kt

@@ -0,0 +1,8 @@
+// "Add 'inner' modifier" "false"
+// ACTION: Implement interface
+// ERROR: Interface is not allowed here
+class A() {
+    inner class B() {
+        interface <caret>C
+    }
+}

idea/testData/quickfix/modifiers/nestedObject.kt

@@ -0,0 +1,8 @@
+// "Add 'inner' modifier" "false"
+// ACTION: Create test
+// ERROR: Object is not allowed here
+class A() {
+    inner class B() {
+        object <caret>C
+    }
+}

idea/testData/quickfix/modifiers/nestedSealedClass.kt

@@ -0,0 +1,10 @@
+// "Add 'inner' modifier" "false"
+// ACTION: Convert to enum class
+// ACTION: Create test
+// ACTION: Implement sealed class
+// ERROR: Class is not allowed here
+class A() {
+    inner class B() {
+        sealed class <caret>C
+    }
+}

idea/tests/org/jetbrains/kotlin/idea/quickfix/QuickFixTestGenerated.java

@@ -7640,12 +7640,54 @@ public class QuickFixTestGenerated extends AbstractQuickFixTest {
             doTest(fileName);
         }
 
+        @TestMetadata("nestedAbstractClass.kt")
+        public void testNestedAbstractClass() throws Exception {
+            String fileName = KotlinTestUtils.navigationMetadata("idea/testData/quickfix/modifiers/nestedAbstractClass.kt");
+            doTest(fileName);
+        }
+
+        @TestMetadata("nestedAnnotationClass.kt")
+        public void testNestedAnnotationClass() throws Exception {
+            String fileName = KotlinTestUtils.navigationMetadata("idea/testData/quickfix/modifiers/nestedAnnotationClass.kt");
+            doTest(fileName);
+        }
+
         @TestMetadata("nestedClassNotAllowed.kt")
         public void testNestedClassNotAllowed() throws Exception {
             String fileName = KotlinTestUtils.navigationMetadata("idea/testData/quickfix/modifiers/nestedClassNotAllowed.kt");
             doTest(fileName);
         }
 
+        @TestMetadata("nestedDataClass.kt")
+        public void testNestedDataClass() throws Exception {
+            String fileName = KotlinTestUtils.navigationMetadata("idea/testData/quickfix/modifiers/nestedDataClass.kt");
+            doTest(fileName);
+        }
+
+        @TestMetadata("nestedEnumClass.kt")
+        public void testNestedEnumClass() throws Exception {
+            String fileName = KotlinTestUtils.navigationMetadata("idea/testData/quickfix/modifiers/nestedEnumClass.kt");
+            doTest(fileName);
+        }
+
+        @TestMetadata("nestedInterface.kt")
+        public void testNestedInterface() throws Exception {
+            String fileName = KotlinTestUtils.navigationMetadata("idea/testData/quickfix/modifiers/nestedInterface.kt");
+            doTest(fileName);
+        }
+
+        @TestMetadata("nestedObject.kt")
+        public void testNestedObject() throws Exception {
+            String fileName = KotlinTestUtils.navigationMetadata("idea/testData/quickfix/modifiers/nestedObject.kt");
+            doTest(fileName);
+        }
+
+        @TestMetadata("nestedSealedClass.kt")
+        public void testNestedSealedClass() throws Exception {
+            String fileName = KotlinTestUtils.navigationMetadata("idea/testData/quickfix/modifiers/nestedSealedClass.kt");
+            doTest(fileName);
+        }
+
         @TestMetadata("noAbstractForAnonymousObject.kt")
         public void testNoAbstractForAnonymousObject() throws Exception {
             String fileName = KotlinTestUtils.navigationMetadata("idea/testData/quickfix/modifiers/noAbstractForAnonymousObject.kt");