FIR: introduce diagnostic NESTED_CLASS_NOT_ALLOWED

compiler/testData/diagnostics/tests/inner/annotationInInnerClass.fir.kt

@@ -1,5 +1,5 @@
 class Outer {
     inner class Inner {
-        annotation class TestNestedAnnotation
+        annotation <!NESTED_CLASS_NOT_ALLOWED!>class TestNestedAnnotation<!>
     }
-}
+}

compiler/testData/diagnostics/tests/inner/enumInInnerClass.fir.kt

@@ -1,5 +1,5 @@
 class Outer {
     inner class Inner {
-        enum class TestNestedEnum
+        <!NESTED_CLASS_NOT_ALLOWED!>enum class TestNestedEnum<!>
     }
-}
+}

compiler/testData/diagnostics/tests/inner/innerClassInEnumEntryClass_lv11.fir.kt

@@ -4,9 +4,9 @@ enum class Enum {
     ENTRY_WITH_CLASS {
         inner class TestInner
 
-        class TestNested
+        <!NESTED_CLASS_NOT_ALLOWED!>class TestNested<!>
 
-        interface TestInterface
+        <!NESTED_CLASS_NOT_ALLOWED!>interface TestInterface<!>
 
         object TestObject
 

compiler/testData/diagnostics/tests/inner/innerClassInEnumEntryClass_lv12.fir.kt

@@ -4,9 +4,9 @@ enum class Enum {
     ENTRY_WITH_CLASS {
         inner class TestInner
 
-        class TestNested
+        <!NESTED_CLASS_NOT_ALLOWED!>class TestNested<!>
 
-        interface TestInterface
+        <!NESTED_CLASS_NOT_ALLOWED!>interface TestInterface<!>
 
         object TestObject
 

compiler/testData/diagnostics/tests/inner/innerClassInEnumEntryClass_lv13.fir.kt

@@ -4,9 +4,9 @@ enum class Enum {
     ENTRY_WITH_CLASS {
         inner class TestInner
 
-        class TestNested
+        <!NESTED_CLASS_NOT_ALLOWED!>class TestNested<!>
 
-        interface TestInterface
+        <!NESTED_CLASS_NOT_ALLOWED!>interface TestInterface<!>
 
         object TestObject
 

compiler/testData/diagnostics/tests/inner/interfaceInInnerClass.fir.kt

@@ -1,5 +1,5 @@
 class Outer {
     inner class Inner {
-        interface TestNestedInterface
+        <!NESTED_CLASS_NOT_ALLOWED!>interface TestNestedInterface<!>
     }
-}
+}

compiler/testData/diagnostics/tests/inner/nestedClassNotAllowed_after.fir.kt

@@ -1,26 +0,0 @@
-// !LANGUAGE: +NestedClassesInEnumEntryShouldBeInner
-
-class A {
-    inner class B {
-        class C
-    }
-    
-    fun foo() {
-        class B {
-            class C
-        }
-    }
-}
-
-fun foo() {
-    class B {
-        class C
-    }
-}
-
-
-enum class E {
-    E1 {
-        class D
-    }
-}

compiler/testData/diagnostics/tests/inner/nestedClassNotAllowed_after.kt

@@ -1,3 +1,4 @@
+// FIR_IDENTICAL
 // !LANGUAGE: +NestedClassesInEnumEntryShouldBeInner
 
 class A {

compiler/testData/diagnostics/tests/inner/nestedClassNotAllowed_before.fir.kt

@@ -2,25 +2,25 @@
 
 class A {
     inner class B {
-        class C
+        <!NESTED_CLASS_NOT_ALLOWED!>class C<!>
     }
     
     fun foo() {
         class B {
-            class C
+            <!NESTED_CLASS_NOT_ALLOWED!>class C<!>
         }
     }
 }
 
 fun foo() {
     class B {
-        class C
+        <!NESTED_CLASS_NOT_ALLOWED!>class C<!>
     }
 }
 
 
 enum class E {
     E1 {
-        class D
+        <!NESTED_CLASS_NOT_ALLOWED!>class D<!>
     }
 }

compiler/testData/diagnostics/tests/inner/nestedObject.fir.kt

@@ -1,12 +1,12 @@
 // SKIP_TXT
 class Outer {
     inner class Inner1 {
-        object Obj1
+        <!NESTED_CLASS_NOT_ALLOWED!>object Obj1<!>
 
-        companion object Obj2
+        companion <!NESTED_CLASS_NOT_ALLOWED!>object Obj2<!>
 
         inner class Inner2 {
-            object Obj3
+            <!NESTED_CLASS_NOT_ALLOWED!>object Obj3<!>
         }
     }
 }