diff --git a/compiler/fir/analysis-tests/testData/resolve/diagnostics/incompatibleModifiers.kt b/compiler/fir/analysis-tests/testData/resolve/diagnostics/incompatibleModifiers.kt
index 4eddabe933f..91e10ac0ec7 100644
--- a/compiler/fir/analysis-tests/testData/resolve/diagnostics/incompatibleModifiers.kt
+++ b/compiler/fir/analysis-tests/testData/resolve/diagnostics/incompatibleModifiers.kt
@@ -1,5 +1,5 @@
 <!INCOMPATIBLE_MODIFIERS!>private<!> <!INCOMPATIBLE_MODIFIERS!>public<!> class B
-<!INCOMPATIBLE_MODIFIERS!>protected<!> <!INCOMPATIBLE_MODIFIERS!>internal<!> class C
+<!WRONG_MODIFIER_CONTAINING_DECLARATION!>protected<!> <!INCOMPATIBLE_MODIFIERS!>internal<!> class C
 
 <!INCOMPATIBLE_MODIFIERS!>final<!> <!INCOMPATIBLE_MODIFIERS!>abstract<!> class D
 <!INCOMPATIBLE_MODIFIERS!>final<!> <!INCOMPATIBLE_MODIFIERS!>open<!> class E
diff --git a/compiler/fir/analysis-tests/testData/resolve/extendedCheckers/RedundantModalityModifierChecker.kt b/compiler/fir/analysis-tests/testData/resolve/extendedCheckers/RedundantModalityModifierChecker.kt
index 483dc715a00..fd0cdf04d80 100644
--- a/compiler/fir/analysis-tests/testData/resolve/extendedCheckers/RedundantModalityModifierChecker.kt
+++ b/compiler/fir/analysis-tests/testData/resolve/extendedCheckers/RedundantModalityModifierChecker.kt
@@ -10,7 +10,7 @@ interface Interface {
     // Redundant
     <!REDUNDANT_MODALITY_MODIFIER!>abstract<!> fun foo()
     // error
-    <!PRIVATE_FUNCTION_WITH_NO_BODY!>private<!> final fun bar()
+    <!PRIVATE_FUNCTION_WITH_NO_BODY!>private<!> <!WRONG_MODIFIER_CONTAINING_DECLARATION!>final<!> fun bar()
 
     <!REDUNDANT_MODALITY_MODIFIER!>open<!> fun goo() {}
     <!REDUNDANT_MODALITY_MODIFIER!>abstract<!> fun tar()
@@ -63,7 +63,7 @@ interface Derived : Interface {
     // Redundant
     override <!REDUNDANT_MODALITY_MODIFIER!>open<!> fun foo() {}
     // error
-    final class Nested
+    <!WRONG_MODIFIER_CONTAINING_DECLARATION!>final<!> class Nested
 }
 // Derived abstract class
 abstract class AbstractDerived1(override final val gav: Int) : Interface {
diff --git a/compiler/fir/analysis-tests/testData/resolve/extendedCheckers/RedundantSetterParameterTypeChecker.kt b/compiler/fir/analysis-tests/testData/resolve/extendedCheckers/RedundantSetterParameterTypeChecker.kt
index 924d58c56d9..4ee0cb63b8e 100644
--- a/compiler/fir/analysis-tests/testData/resolve/extendedCheckers/RedundantSetterParameterTypeChecker.kt
+++ b/compiler/fir/analysis-tests/testData/resolve/extendedCheckers/RedundantSetterParameterTypeChecker.kt
@@ -4,7 +4,7 @@ annotation class Ann
 
 var <!REDECLARATION!>x<!>: Int
     get() = 1
-    set(@Ann private x) { }
+    set(@Ann <!WRONG_MODIFIER_TARGET!>private<!> x) { }
 
 
 var <!REDECLARATION!>x<!>: String = ""
diff --git a/compiler/fir/checkers/checkers-component-generator/src/org/jetbrains/kotlin/fir/checkers/generator/diagnostics/FirDiagnosticsList.kt b/compiler/fir/checkers/checkers-component-generator/src/org/jetbrains/kotlin/fir/checkers/generator/diagnostics/FirDiagnosticsList.kt
index 389447fd655..16c762b1616 100644
--- a/compiler/fir/checkers/checkers-component-generator/src/org/jetbrains/kotlin/fir/checkers/generator/diagnostics/FirDiagnosticsList.kt
+++ b/compiler/fir/checkers/checkers-component-generator/src/org/jetbrains/kotlin/fir/checkers/generator/diagnostics/FirDiagnosticsList.kt
@@ -339,6 +339,14 @@ object DIAGNOSTICS_LIST : DiagnosticList("FirErrors") {
         val INFIX_MODIFIER_REQUIRED by error<PsiElement> {
             parameter<FirNamedFunctionSymbol>("functionSymbol")
         }
+        val WRONG_MODIFIER_CONTAINING_DECLARATION by error<PsiElement> {
+            parameter<String>("modifier")
+            parameter<String>("target")
+        }
+        val DEPRECATED_MODIFIER_CONTAINING_DECLARATION by warning<PsiElement> {
+            parameter<String>("modifier")
+            parameter<String>("target")
+        }
     }
 
     val INLINE_CLASSES by object : DiagnosticGroup("Inline classes") {
diff --git a/compiler/fir/checkers/gen/org/jetbrains/kotlin/fir/analysis/diagnostics/FirErrors.kt b/compiler/fir/checkers/gen/org/jetbrains/kotlin/fir/analysis/diagnostics/FirErrors.kt
index a76a67cf0e8..49266fcf60b 100644
--- a/compiler/fir/checkers/gen/org/jetbrains/kotlin/fir/analysis/diagnostics/FirErrors.kt
+++ b/compiler/fir/checkers/gen/org/jetbrains/kotlin/fir/analysis/diagnostics/FirErrors.kt
@@ -264,6 +264,8 @@ object FirErrors {
     val WRONG_MODIFIER_TARGET by error2<PsiElement, String, String>()
     val OPERATOR_MODIFIER_REQUIRED by error2<PsiElement, FirNamedFunctionSymbol, String>()
     val INFIX_MODIFIER_REQUIRED by error1<PsiElement, FirNamedFunctionSymbol>()
+    val WRONG_MODIFIER_CONTAINING_DECLARATION by error2<PsiElement, String, String>()
+    val DEPRECATED_MODIFIER_CONTAINING_DECLARATION by warning2<PsiElement, String, String>()
 
     // Inline classes
     val INLINE_CLASS_NOT_TOP_LEVEL by error0<KtDeclaration>(SourceElementPositioningStrategies.INLINE_OR_VALUE_MODIFIER)
diff --git a/compiler/fir/checkers/src/org/jetbrains/kotlin/fir/analysis/checkers/declaration/FirModifierChecker.kt b/compiler/fir/checkers/src/org/jetbrains/kotlin/fir/analysis/checkers/declaration/FirModifierChecker.kt
index 14bca5dbd79..38ebcf55443 100644
--- a/compiler/fir/checkers/src/org/jetbrains/kotlin/fir/analysis/checkers/declaration/FirModifierChecker.kt
+++ b/compiler/fir/checkers/src/org/jetbrains/kotlin/fir/analysis/checkers/declaration/FirModifierChecker.kt
@@ -6,9 +6,13 @@
 package org.jetbrains.kotlin.fir.analysis.checkers.declaration
 
 import org.jetbrains.kotlin.descriptors.annotations.KotlinTarget
+import org.jetbrains.kotlin.descriptors.annotations.KotlinTarget.*
+import org.jetbrains.kotlin.descriptors.annotations.KotlinTarget.Companion.classActualTargets
+import org.jetbrains.kotlin.fir.FirFakeSourceElementKind
 import org.jetbrains.kotlin.fir.FirSourceElement
 import org.jetbrains.kotlin.fir.analysis.checkers.*
 import org.jetbrains.kotlin.fir.analysis.checkers.context.CheckerContext
+import org.jetbrains.kotlin.fir.analysis.checkers.context.findClosest
 import org.jetbrains.kotlin.fir.analysis.diagnostics.DiagnosticReporter
 import org.jetbrains.kotlin.fir.analysis.diagnostics.FirDiagnosticFactory2
 import org.jetbrains.kotlin.fir.analysis.diagnostics.FirErrors
@@ -54,12 +58,34 @@ object FirModifierChecker : FirBasicDeclarationChecker() {
         val reportedNodes = hashSetOf<FirModifier<*>>()
         val actualTargets = getActualTargetList(owner).defaultTargets
 
+        val parent = context.findClosest<FirDeclaration> {
+            it !is FirPrimaryConstructor &&
+                    it !is FirProperty &&
+                    it.source?.kind !is FirFakeSourceElementKind
+        }
+
+        val actualParents = when (parent) {
+            is FirAnonymousObject -> listOf(LOCAL_CLASS, CLASS)
+            is FirClass -> classActualTargets(
+                parent.classKind,
+                isInnerClass = (parent as? FirMemberDeclaration)?.isInner ?: false,
+                isCompanionObject = (parent as? FirRegularClass)?.isCompanion ?: false,
+                isLocalClass = parent.isLocal
+            )
+            is FirPropertyAccessor -> listOf(if (parent.isSetter) PROPERTY_SETTER else PROPERTY_GETTER)
+            is FirFunction -> listOf(FUNCTION)
+            is FirEnumEntry -> listOf(ENUM_ENTRY, PROPERTY, FIELD)
+            else -> listOf(FILE)
+        }
+
         val modifiers = list.modifiers
         for ((secondIndex, secondModifier) in modifiers.withIndex()) {
             for (firstIndex in 0 until secondIndex) {
                 checkCompatibilityType(modifiers[firstIndex], secondModifier, reporter, reportedNodes, owner, context)
             }
             if (secondModifier !in reportedNodes) {
+                val modifierSource = secondModifier.source
+                val modifierType = getKeywordType(secondModifier)
                 when {
                     !checkTarget(modifierSource, modifierType, actualTargets, parent, context, reporter) -> reportedNodes += secondModifier
                     !checkParent(modifierSource, modifierType, actualParents, context, reporter) -> reportedNodes += secondModifier
@@ -146,14 +172,13 @@ object FirModifierChecker : FirBasicDeclarationChecker() {
     }
 
     private fun checkTarget(
-        modifier: FirModifier<*>,
+        modifierSource: FirSourceElement,
+        modifierType: KeywordType,
         actualTargets: List<KotlinTarget>,
         parent: FirDeclaration?,
         context: CheckerContext,
         reporter: DiagnosticReporter
     ): Boolean {
-        val modifierType = getKeywordType(modifier)
-
         fun checkModifier(factory: FirDiagnosticFactory2<String, String>): Boolean {
             val map = when (factory) {
                 FirErrors.WRONG_MODIFIER_TARGET -> possibleTargetMap
@@ -168,7 +193,7 @@ object FirModifierChecker : FirBasicDeclarationChecker() {
             }
             if (checkResult) {
                 reporter.reportOn(
-                    modifier.source,
+                    modifierSource,
                     factory,
                     modifierType.render(),
                     actualTargets.firstOrThis(),
@@ -193,7 +218,7 @@ object FirModifierChecker : FirBasicDeclarationChecker() {
         val deprecatedModifierReplacement = deprecatedModifierMap[modifierType]
         if (deprecatedModifierReplacement != null) {
             reporter.reportOn(
-                modifier.source,
+                modifierSource,
                 FirErrors.DEPRECATED_MODIFIER,
                 modifierType.render(),
                 deprecatedModifierReplacement.render(),
@@ -206,6 +231,39 @@ object FirModifierChecker : FirBasicDeclarationChecker() {
         return true
     }
 
+    private fun checkParent(
+        modifierSource: FirSourceElement,
+        modifierType: KeywordType,
+        actualParents: List<KotlinTarget>,
+        context: CheckerContext,
+        reporter: DiagnosticReporter
+    ): Boolean {
+        val deprecatedParents = deprecatedParentTargetMap[modifierType]
+        if (deprecatedParents != null && actualParents.any { it in deprecatedParents }) {
+            reporter.reportOn(
+                modifierSource,
+                FirErrors.DEPRECATED_MODIFIER_CONTAINING_DECLARATION,
+                modifierType.render(),
+                actualParents.firstOrThis(),
+                context
+            )
+            return true
+        }
+
+        val possibleParentPredicate = possibleParentTargetPredicateMap[modifierType] ?: return true
+        if (actualParents.any { possibleParentPredicate.isAllowed(it, context.session.languageVersionSettings) }) return true
+
+        reporter.reportOn(
+            modifierSource,
+            FirErrors.WRONG_MODIFIER_CONTAINING_DECLARATION,
+            modifierType.render(),
+            actualParents.firstOrThis(),
+            context
+        )
+
+        return false
+    }
+
     private fun List<KotlinTarget>.firstOrThis(): String {
         return firstOrNull()?.description ?: "this"
     }
diff --git a/compiler/fir/checkers/src/org/jetbrains/kotlin/fir/analysis/diagnostics/FirDefaultErrorMessages.kt b/compiler/fir/checkers/src/org/jetbrains/kotlin/fir/analysis/diagnostics/FirDefaultErrorMessages.kt
index 1427580d03c..8bc8c489322 100644
--- a/compiler/fir/checkers/src/org/jetbrains/kotlin/fir/analysis/diagnostics/FirDefaultErrorMessages.kt
+++ b/compiler/fir/checkers/src/org/jetbrains/kotlin/fir/analysis/diagnostics/FirDefaultErrorMessages.kt
@@ -126,6 +126,7 @@ import org.jetbrains.kotlin.fir.analysis.diagnostics.FirErrors.DELEGATION_IN_INT
 import org.jetbrains.kotlin.fir.analysis.diagnostics.FirErrors.DELEGATION_NOT_TO_INTERFACE
 import org.jetbrains.kotlin.fir.analysis.diagnostics.FirErrors.DELEGATION_SUPER_CALL_IN_ENUM_CONSTRUCTOR
 import org.jetbrains.kotlin.fir.analysis.diagnostics.FirErrors.DEPRECATED_MODIFIER
+import org.jetbrains.kotlin.fir.analysis.diagnostics.FirErrors.DEPRECATED_MODIFIER_CONTAINING_DECLARATION
 import org.jetbrains.kotlin.fir.analysis.diagnostics.FirErrors.DEPRECATED_MODIFIER_FOR_TARGET
 import org.jetbrains.kotlin.fir.analysis.diagnostics.FirErrors.DEPRECATED_MODIFIER_PAIR
 import org.jetbrains.kotlin.fir.analysis.diagnostics.FirErrors.DEPRECATED_SINCE_KOTLIN_OUTSIDE_KOTLIN_SUBPACKAGE
@@ -465,6 +466,7 @@ import org.jetbrains.kotlin.fir.analysis.diagnostics.FirErrors.WRONG_ANNOTATION_
 import org.jetbrains.kotlin.fir.analysis.diagnostics.FirErrors.WRONG_ANNOTATION_TARGET_WITH_USE_SITE_TARGET
 import org.jetbrains.kotlin.fir.analysis.diagnostics.FirErrors.WRONG_GETTER_RETURN_TYPE
 import org.jetbrains.kotlin.fir.analysis.diagnostics.FirErrors.WRONG_INVOCATION_KIND
+import org.jetbrains.kotlin.fir.analysis.diagnostics.FirErrors.WRONG_MODIFIER_CONTAINING_DECLARATION
 import org.jetbrains.kotlin.fir.analysis.diagnostics.FirErrors.WRONG_MODIFIER_TARGET
 import org.jetbrains.kotlin.fir.analysis.diagnostics.FirErrors.WRONG_NUMBER_OF_TYPE_ARGUMENTS
 import org.jetbrains.kotlin.fir.analysis.diagnostics.FirErrors.WRONG_SETTER_PARAMETER_TYPE
@@ -737,6 +739,8 @@ class FirDefaultErrorMessages {
             map.put(REDUNDANT_OPEN_IN_INTERFACE, "Modifier 'open' is redundant for abstract interface members")
             map.put(WRONG_MODIFIER_TARGET, "Modifier ''{0}'' is not applicable to ''{1}''", STRING, STRING)
             map.put(INFIX_MODIFIER_REQUIRED, "''infix'' modifier is required on ''{0}''", TO_STRING)
+            map.put(WRONG_MODIFIER_CONTAINING_DECLARATION, "Modifier ''{0}'' is not applicable inside ''{1}''", STRING, STRING)
+            map.put(DEPRECATED_MODIFIER_CONTAINING_DECLARATION, "Modifier ''{0}'' is deprecated inside ''{1}''", STRING, STRING)
 
             // Classes and interfaces
             map.put(SUPERTYPE_NOT_INITIALIZED, "This type has a constructor, and thus must be initialized here")
diff --git a/compiler/fir/tree/gen/org/jetbrains/kotlin/fir/declarations/builder/FirPrimaryConstructorBuilder.kt b/compiler/fir/tree/gen/org/jetbrains/kotlin/fir/declarations/builder/FirPrimaryConstructorBuilder.kt
index 05d5bb0c751..1049561902f 100644
--- a/compiler/fir/tree/gen/org/jetbrains/kotlin/fir/declarations/builder/FirPrimaryConstructorBuilder.kt
+++ b/compiler/fir/tree/gen/org/jetbrains/kotlin/fir/declarations/builder/FirPrimaryConstructorBuilder.kt
@@ -6,6 +6,7 @@
 package org.jetbrains.kotlin.fir.declarations.builder
 
 import kotlin.contracts.*
+import org.jetbrains.kotlin.fir.FirImplementationDetail
 import org.jetbrains.kotlin.fir.FirModuleData
 import org.jetbrains.kotlin.fir.FirSourceElement
 import org.jetbrains.kotlin.fir.builder.FirAnnotationContainerBuilder
@@ -55,6 +56,7 @@ class FirPrimaryConstructorBuilder : FirAbstractConstructorBuilder, FirAnnotatio
     override var delegatedConstructor: FirDelegatedConstructorCall? = null
     override var body: FirBlock? = null
 
+    @OptIn(FirImplementationDetail::class)
     override fun build(): FirConstructor {
         return FirPrimaryConstructor(
             source,
diff --git a/compiler/fir/tree/gen/org/jetbrains/kotlin/fir/declarations/impl/FirPrimaryConstructor.kt b/compiler/fir/tree/gen/org/jetbrains/kotlin/fir/declarations/impl/FirPrimaryConstructor.kt
index 57638d8e42b..63839ec8bd2 100644
--- a/compiler/fir/tree/gen/org/jetbrains/kotlin/fir/declarations/impl/FirPrimaryConstructor.kt
+++ b/compiler/fir/tree/gen/org/jetbrains/kotlin/fir/declarations/impl/FirPrimaryConstructor.kt
@@ -5,6 +5,7 @@
 
 package org.jetbrains.kotlin.fir.declarations.impl
 
+import org.jetbrains.kotlin.fir.FirImplementationDetail
 import org.jetbrains.kotlin.fir.FirModuleData
 import org.jetbrains.kotlin.fir.FirSourceElement
 import org.jetbrains.kotlin.fir.declarations.DeprecationsPerUseSite
@@ -30,7 +31,7 @@ import org.jetbrains.kotlin.fir.visitors.*
  * DO NOT MODIFY IT MANUALLY
  */
 
-internal class FirPrimaryConstructor(
+class FirPrimaryConstructor @FirImplementationDetail constructor(
     override val source: FirSourceElement?,
     override val moduleData: FirModuleData,
     @Volatile
diff --git a/compiler/fir/tree/tree-generator/src/org/jetbrains/kotlin/fir/tree/generator/ImplementationConfigurator.kt b/compiler/fir/tree/tree-generator/src/org/jetbrains/kotlin/fir/tree/generator/ImplementationConfigurator.kt
index 0e3eec7fbd9..74f1a1f53f1 100644
--- a/compiler/fir/tree/tree-generator/src/org/jetbrains/kotlin/fir/tree/generator/ImplementationConfigurator.kt
+++ b/compiler/fir/tree/tree-generator/src/org/jetbrains/kotlin/fir/tree/generator/ImplementationConfigurator.kt
@@ -22,6 +22,7 @@ object ImplementationConfigurator : AbstractFirTreeImplementationConfigurator()
         }
 
         impl(constructor, "FirPrimaryConstructor") {
+            publicImplementation()
             defaultTrue("isPrimary", withGetter = true)
         }
 
diff --git a/compiler/testData/diagnostics/tests/annotations/nestedClassesInAnnotations.fir.kt b/compiler/testData/diagnostics/tests/annotations/nestedClassesInAnnotations.fir.kt
deleted file mode 100644
index 15ecebd3b50..00000000000
--- a/compiler/testData/diagnostics/tests/annotations/nestedClassesInAnnotations.fir.kt
+++ /dev/null
@@ -1,23 +0,0 @@
-// !LANGUAGE: +NestedClassesInAnnotations
-
-annotation class Foo {
-    class Nested
-
-    inner class Inner
-
-    enum class E { A, B }
-    object O
-    interface I
-    annotation class Anno(val e: E)
-
-    companion object {
-        val x = 1
-        const val y = ""
-    }
-
-
-    <!ANNOTATION_CLASS_MEMBER!>constructor(s: Int) {}<!>
-    <!ANNOTATION_CLASS_MEMBER!>init {}<!>
-    <!ANNOTATION_CLASS_MEMBER!>fun function() {}<!>
-    <!ANNOTATION_CLASS_MEMBER!>val property get() = Unit<!>
-}
diff --git a/compiler/testData/diagnostics/tests/annotations/nestedClassesInAnnotations.kt b/compiler/testData/diagnostics/tests/annotations/nestedClassesInAnnotations.kt
index dac8f1ed1c5..14801a4af9a 100644
--- a/compiler/testData/diagnostics/tests/annotations/nestedClassesInAnnotations.kt
+++ b/compiler/testData/diagnostics/tests/annotations/nestedClassesInAnnotations.kt
@@ -1,3 +1,4 @@
+// FIR_IDENTICAL
 // !LANGUAGE: +NestedClassesInAnnotations
 
 annotation class Foo {
diff --git a/compiler/testData/diagnostics/tests/classObjects/ClassObjects.fir.kt b/compiler/testData/diagnostics/tests/classObjects/ClassObjects.fir.kt
deleted file mode 100644
index 0928188e162..00000000000
--- a/compiler/testData/diagnostics/tests/classObjects/ClassObjects.fir.kt
+++ /dev/null
@@ -1,43 +0,0 @@
-// !DIAGNOSTICS: -DUPLICATE_CLASS_NAMES
-package Jet86
-
-class A {
-  companion <!REDECLARATION!>object<!> {
-    val x = 1
-  }
-  <!MANY_COMPANION_OBJECTS!>companion<!> <!REDECLARATION!>object<!> {
-    val x = 1
-  }
-}
-
-class AA {
-  companion object {
-    val x = 1
-  }
-  <!MANY_COMPANION_OBJECTS!>companion<!> object A {
-    val x = 1
-  }
-    <!MANY_COMPANION_OBJECTS!>companion<!> object AA {
-    val x = 1
-  }
-}
-
-class B() {
-  val x = 12
-}
-
-object b {
-  companion object {
-    val x = 1
-  } // error
-}
-
-val a = A.x
-val c = B.<!UNRESOLVED_REFERENCE!>x<!>
-val d = b.<!UNRESOLVED_REFERENCE!>x<!>
-
-val s = <!NO_COMPANION_OBJECT!>System<!>  // error
-fun test() {
-  System.out.println()
-  java.lang.System.out.println()
-}
\ No newline at end of file
diff --git a/compiler/testData/diagnostics/tests/classObjects/ClassObjects.kt b/compiler/testData/diagnostics/tests/classObjects/ClassObjects.kt
index 95191baeb53..b359d38303d 100644
--- a/compiler/testData/diagnostics/tests/classObjects/ClassObjects.kt
+++ b/compiler/testData/diagnostics/tests/classObjects/ClassObjects.kt
@@ -1,3 +1,4 @@
+// FIR_IDENTICAL
 // !DIAGNOSTICS: -DUPLICATE_CLASS_NAMES
 package Jet86
 
diff --git a/compiler/testData/diagnostics/tests/classObjects/classObjectInLocalClass.fir.kt b/compiler/testData/diagnostics/tests/classObjects/classObjectInLocalClass.fir.kt
deleted file mode 100644
index 5b91a35a64e..00000000000
--- a/compiler/testData/diagnostics/tests/classObjects/classObjectInLocalClass.fir.kt
+++ /dev/null
@@ -1,9 +0,0 @@
-fun test() {
-    class A {
-        companion object {}
-    }
-
-    object {
-        companion object {}
-    }
-}
\ No newline at end of file
diff --git a/compiler/testData/diagnostics/tests/classObjects/classObjectInLocalClass.kt b/compiler/testData/diagnostics/tests/classObjects/classObjectInLocalClass.kt
index d9d28a48188..f775b4e0440 100644
--- a/compiler/testData/diagnostics/tests/classObjects/classObjectInLocalClass.kt
+++ b/compiler/testData/diagnostics/tests/classObjects/classObjectInLocalClass.kt
@@ -1,3 +1,4 @@
+// FIR_IDENTICAL
 fun test() {
     class A {
         <!WRONG_MODIFIER_CONTAINING_DECLARATION!>companion<!> object {}
diff --git a/compiler/testData/diagnostics/tests/classObjects/multipleDissallowedDefaultObjects.fir.kt b/compiler/testData/diagnostics/tests/classObjects/multipleDissallowedDefaultObjects.fir.kt
index d5b96e7c186..0c514c91c41 100644
--- a/compiler/testData/diagnostics/tests/classObjects/multipleDissallowedDefaultObjects.fir.kt
+++ b/compiler/testData/diagnostics/tests/classObjects/multipleDissallowedDefaultObjects.fir.kt
@@ -9,9 +9,9 @@ class A {
 }
 
 object O {
-    companion object A
+    <!WRONG_MODIFIER_CONTAINING_DECLARATION!>companion<!> object A
 
-    <!MANY_COMPANION_OBJECTS!>companion<!> object B
+    <!MANY_COMPANION_OBJECTS, WRONG_MODIFIER_CONTAINING_DECLARATION!>companion<!> object B
 
-    <!MANY_COMPANION_OBJECTS!>companion<!> object C
+    <!MANY_COMPANION_OBJECTS, WRONG_MODIFIER_CONTAINING_DECLARATION!>companion<!> object C
 }
diff --git a/compiler/testData/diagnostics/tests/dataClasses/implementTraitWhichHasFinalComponent1.fir.kt b/compiler/testData/diagnostics/tests/dataClasses/implementTraitWhichHasFinalComponent1.fir.kt
deleted file mode 100644
index 8efc12249f6..00000000000
--- a/compiler/testData/diagnostics/tests/dataClasses/implementTraitWhichHasFinalComponent1.fir.kt
+++ /dev/null
@@ -1,5 +0,0 @@
-interface T {
-    final fun component1(): Int = 42
-}
-
-<!DATA_CLASS_OVERRIDE_CONFLICT!>data<!> class A(val x: Int) : T
diff --git a/compiler/testData/diagnostics/tests/dataClasses/implementTraitWhichHasFinalComponent1.kt b/compiler/testData/diagnostics/tests/dataClasses/implementTraitWhichHasFinalComponent1.kt
index 40eb1b8e496..3bcc1993bb4 100644
--- a/compiler/testData/diagnostics/tests/dataClasses/implementTraitWhichHasFinalComponent1.kt
+++ b/compiler/testData/diagnostics/tests/dataClasses/implementTraitWhichHasFinalComponent1.kt
@@ -1,3 +1,4 @@
+// FIR_IDENTICAL
 interface T {
     <!WRONG_MODIFIER_CONTAINING_DECLARATION!>final<!> fun component1(): Int = 42
 }
diff --git a/compiler/testData/diagnostics/tests/dataClasses/innerOuterDataClass.fir.kt b/compiler/testData/diagnostics/tests/dataClasses/innerOuterDataClass.fir.kt
deleted file mode 100644
index a7a16e75490..00000000000
--- a/compiler/testData/diagnostics/tests/dataClasses/innerOuterDataClass.fir.kt
+++ /dev/null
@@ -1 +0,0 @@
-<!INCOMPATIBLE_MODIFIERS!>inner<!> <!INCOMPATIBLE_MODIFIERS!>data<!> class Outer(val x: Int)
\ No newline at end of file
diff --git a/compiler/testData/diagnostics/tests/dataClasses/innerOuterDataClass.kt b/compiler/testData/diagnostics/tests/dataClasses/innerOuterDataClass.kt
index 1695db0dcfc..5f70eef5645 100644
--- a/compiler/testData/diagnostics/tests/dataClasses/innerOuterDataClass.kt
+++ b/compiler/testData/diagnostics/tests/dataClasses/innerOuterDataClass.kt
@@ -1 +1,2 @@
+// FIR_IDENTICAL
 <!WRONG_MODIFIER_CONTAINING_DECLARATION!>inner<!> <!INCOMPATIBLE_MODIFIERS!>data<!> class Outer(val x: Int)
\ No newline at end of file
diff --git a/compiler/testData/diagnostics/tests/declarationChecks/kt2397.fir.kt b/compiler/testData/diagnostics/tests/declarationChecks/kt2397.fir.kt
deleted file mode 100644
index 2de9ebda214..00000000000
--- a/compiler/testData/diagnostics/tests/declarationChecks/kt2397.fir.kt
+++ /dev/null
@@ -1,17 +0,0 @@
-//KT-2397 Prohibit final methods in traits with no implementation
-package a
-
-interface T {
-    final fun foo()
-    final val b : Int
-
-    final fun bar() {}
-    final val c : Int
-       get() = 42
-
-    final val d = <!PROPERTY_INITIALIZER_IN_INTERFACE!>1<!>
-}
-
-class A {
-    <!NON_ABSTRACT_FUNCTION_WITH_NO_BODY!>final fun foo()<!>
-}
\ No newline at end of file
diff --git a/compiler/testData/diagnostics/tests/declarationChecks/kt2397.kt b/compiler/testData/diagnostics/tests/declarationChecks/kt2397.kt
index a7e8aabcda4..0ed0c001443 100644
--- a/compiler/testData/diagnostics/tests/declarationChecks/kt2397.kt
+++ b/compiler/testData/diagnostics/tests/declarationChecks/kt2397.kt
@@ -1,3 +1,4 @@
+// FIR_IDENTICAL
 //KT-2397 Prohibit final methods in traits with no implementation
 package a
 
diff --git a/compiler/testData/diagnostics/tests/declarationChecks/propertyInPackageHasNoInheritVisibility.fir.kt b/compiler/testData/diagnostics/tests/declarationChecks/propertyInPackageHasNoInheritVisibility.fir.kt
deleted file mode 100644
index 470d27bd13a..00000000000
--- a/compiler/testData/diagnostics/tests/declarationChecks/propertyInPackageHasNoInheritVisibility.fir.kt
+++ /dev/null
@@ -1,10 +0,0 @@
-package d
-
-<!WRONG_MODIFIER_TARGET!>override<!> val f : ()-> Int = { 12 }
-
-fun test() {
-    f()
-}
-
-var g: Int = 1
-    protected set(i: Int) {}
diff --git a/compiler/testData/diagnostics/tests/declarationChecks/propertyInPackageHasNoInheritVisibility.kt b/compiler/testData/diagnostics/tests/declarationChecks/propertyInPackageHasNoInheritVisibility.kt
index b086dbaaaa0..cc8a740db0f 100644
--- a/compiler/testData/diagnostics/tests/declarationChecks/propertyInPackageHasNoInheritVisibility.kt
+++ b/compiler/testData/diagnostics/tests/declarationChecks/propertyInPackageHasNoInheritVisibility.kt
@@ -1,3 +1,4 @@
+// FIR_IDENTICAL
 package d
 
 <!WRONG_MODIFIER_TARGET!>override<!> val f : ()-> Int = { 12 }
diff --git a/compiler/testData/diagnostics/tests/enum/enumEntryCannotHaveClassObject.fir.kt b/compiler/testData/diagnostics/tests/enum/enumEntryCannotHaveClassObject.fir.kt
deleted file mode 100644
index 308f3146a45..00000000000
--- a/compiler/testData/diagnostics/tests/enum/enumEntryCannotHaveClassObject.fir.kt
+++ /dev/null
@@ -1,11 +0,0 @@
-enum class E {
-    FIRST,
-
-    SECOND {
-        companion object {
-            fun foo() = 42
-        }
-    };
-}
-
-fun f() = E.SECOND.<!UNRESOLVED_REFERENCE!>foo<!>()
diff --git a/compiler/testData/diagnostics/tests/enum/enumEntryCannotHaveClassObject.kt b/compiler/testData/diagnostics/tests/enum/enumEntryCannotHaveClassObject.kt
index e65fd1ed973..d1add84ef55 100644
--- a/compiler/testData/diagnostics/tests/enum/enumEntryCannotHaveClassObject.kt
+++ b/compiler/testData/diagnostics/tests/enum/enumEntryCannotHaveClassObject.kt
@@ -1,3 +1,4 @@
+// FIR_IDENTICAL
 enum class E {
     FIRST,
 
diff --git a/compiler/testData/diagnostics/tests/inlineClasses/inlineClassDeclarationCheck.fir.kt b/compiler/testData/diagnostics/tests/inlineClasses/inlineClassDeclarationCheck.fir.kt
index b8e4a77d9da..8f6a1027058 100644
--- a/compiler/testData/diagnostics/tests/inlineClasses/inlineClassDeclarationCheck.fir.kt
+++ b/compiler/testData/diagnostics/tests/inlineClasses/inlineClassDeclarationCheck.fir.kt
@@ -16,7 +16,7 @@ inline class A9(final val x: Int)
 class B1 {
     companion object {
         inline class C1(val x: Int)
-        inner <!INLINE_CLASS_NOT_TOP_LEVEL!>inline<!> class C11(val x: Int)
+        <!WRONG_MODIFIER_CONTAINING_DECLARATION!>inner<!> <!INLINE_CLASS_NOT_TOP_LEVEL!>inline<!> class C11(val x: Int)
     }
 
     inline class C2(val x: Int)
@@ -25,7 +25,7 @@ class B1 {
 
 object B2 {
     inline class C3(val x: Int)
-    inner <!INLINE_CLASS_NOT_TOP_LEVEL!>inline<!> class C31(val x: Int)
+    <!WRONG_MODIFIER_CONTAINING_DECLARATION!>inner<!> <!INLINE_CLASS_NOT_TOP_LEVEL!>inline<!> class C31(val x: Int)
 }
 
 fun foo() {
diff --git a/compiler/testData/diagnostics/tests/inner/deepInnerClass.fir.kt b/compiler/testData/diagnostics/tests/inner/deepInnerClass.fir.kt
index bacd454df96..abf66cb2ff0 100644
--- a/compiler/testData/diagnostics/tests/inner/deepInnerClass.fir.kt
+++ b/compiler/testData/diagnostics/tests/inner/deepInnerClass.fir.kt
@@ -4,11 +4,11 @@ class A<T> {
     class B {
         fun test() {
             class C<W>() : P<W, <!UNRESOLVED_REFERENCE!>T<!>> {
-                companion object : P<W, <!UNRESOLVED_REFERENCE!>T<!>> {
+                <!WRONG_MODIFIER_CONTAINING_DECLARATION!>companion<!> object : P<W, <!UNRESOLVED_REFERENCE!>T<!>> {
                 }
 
                 inner class D : P<W, <!UNRESOLVED_REFERENCE!>T<!>>
             }
         }
     }
-}
\ No newline at end of file
+}
diff --git a/compiler/testData/diagnostics/tests/inner/illegalModifier.fir.kt b/compiler/testData/diagnostics/tests/inner/illegalModifier.fir.kt
deleted file mode 100644
index e69de29bb2d..00000000000
diff --git a/compiler/testData/diagnostics/tests/inner/illegalModifier_lv12.fir.kt b/compiler/testData/diagnostics/tests/inner/illegalModifier_lv12.fir.kt
deleted file mode 100644
index e69de29bb2d..00000000000
diff --git a/compiler/testData/diagnostics/tests/inner/innerClassInEnumEntryClass_lv11.fir.kt b/compiler/testData/diagnostics/tests/inner/innerClassInEnumEntryClass_lv11.fir.kt
index 56810f3209f..f0125c67b6d 100644
--- a/compiler/testData/diagnostics/tests/inner/innerClassInEnumEntryClass_lv11.fir.kt
+++ b/compiler/testData/diagnostics/tests/inner/innerClassInEnumEntryClass_lv11.fir.kt
@@ -2,7 +2,7 @@
 
 enum class Enum {
     ENTRY_WITH_CLASS {
-        inner class TestInner
+        <!WRONG_MODIFIER_CONTAINING_DECLARATION!>inner<!> class TestInner
 
         <!NESTED_CLASS_NOT_ALLOWED!>class TestNested<!>
 
@@ -14,6 +14,6 @@ enum class Enum {
             OTHER_ENTRY
         }
 
-        companion object {}
+        <!WRONG_MODIFIER_CONTAINING_DECLARATION!>companion<!> object {}
     }
 }
diff --git a/compiler/testData/diagnostics/tests/inner/innerClassInEnumEntryClass_lv12.fir.kt b/compiler/testData/diagnostics/tests/inner/innerClassInEnumEntryClass_lv12.fir.kt
index 05805836b63..ddbafdd925b 100644
--- a/compiler/testData/diagnostics/tests/inner/innerClassInEnumEntryClass_lv12.fir.kt
+++ b/compiler/testData/diagnostics/tests/inner/innerClassInEnumEntryClass_lv12.fir.kt
@@ -14,6 +14,6 @@ enum class Enum {
             OTHER_ENTRY
         }
 
-        companion object {}
+        <!WRONG_MODIFIER_CONTAINING_DECLARATION!>companion<!> object {}
     }
 }
diff --git a/compiler/testData/diagnostics/tests/inner/innerClassInEnumEntryClass_lv13.fir.kt b/compiler/testData/diagnostics/tests/inner/innerClassInEnumEntryClass_lv13.fir.kt
index 96a4be9033e..7632eae4f5d 100644
--- a/compiler/testData/diagnostics/tests/inner/innerClassInEnumEntryClass_lv13.fir.kt
+++ b/compiler/testData/diagnostics/tests/inner/innerClassInEnumEntryClass_lv13.fir.kt
@@ -14,6 +14,6 @@ enum class Enum {
             OTHER_ENTRY
         }
 
-        companion object {}
+        <!WRONG_MODIFIER_CONTAINING_DECLARATION!>companion<!> object {}
     }
 }
diff --git a/compiler/testData/diagnostics/tests/modifiers/annotations.fir.kt b/compiler/testData/diagnostics/tests/modifiers/annotations.fir.kt
deleted file mode 100644
index 6d86371ce29..00000000000
--- a/compiler/testData/diagnostics/tests/modifiers/annotations.fir.kt
+++ /dev/null
@@ -1,12 +0,0 @@
-annotation class My(
-    public val x: Int,
-    protected val y: Int,
-    internal val z: Int,
-    private val w: Int
-)
-
-open class Your {
-    open val x: Int = 0
-}
-
-annotation class His(override val x: Int): <!SUPERTYPES_FOR_ANNOTATION_CLASS!>Your()<!>
diff --git a/compiler/testData/diagnostics/tests/modifiers/annotations.kt b/compiler/testData/diagnostics/tests/modifiers/annotations.kt
index 65427abc29c..127aed1e44d 100644
--- a/compiler/testData/diagnostics/tests/modifiers/annotations.kt
+++ b/compiler/testData/diagnostics/tests/modifiers/annotations.kt
@@ -1,3 +1,4 @@
+// FIR_IDENTICAL
 annotation class My(
     public val x: Int,
     <!WRONG_MODIFIER_CONTAINING_DECLARATION!>protected<!> val y: Int,
diff --git a/compiler/testData/diagnostics/tests/modifiers/defaultModifier.fir.kt b/compiler/testData/diagnostics/tests/modifiers/defaultModifier.fir.kt
deleted file mode 100644
index e69de29bb2d..00000000000
diff --git a/compiler/testData/diagnostics/tests/modifiers/internalInInterface.fir.kt b/compiler/testData/diagnostics/tests/modifiers/internalInInterface.fir.kt
deleted file mode 100644
index 5b1a334f17a..00000000000
--- a/compiler/testData/diagnostics/tests/modifiers/internalInInterface.fir.kt
+++ /dev/null
@@ -1,7 +0,0 @@
-interface My {
-    internal val x: Int
-    internal val xxx: Int
-        get() = 0
-    internal fun foo(): Int
-    internal fun bar() = 42
-}
diff --git a/compiler/testData/diagnostics/tests/modifiers/internalInInterface.kt b/compiler/testData/diagnostics/tests/modifiers/internalInInterface.kt
index 144a361742f..3d0bfd68317 100644
--- a/compiler/testData/diagnostics/tests/modifiers/internalInInterface.kt
+++ b/compiler/testData/diagnostics/tests/modifiers/internalInInterface.kt
@@ -1,3 +1,4 @@
+// FIR_IDENTICAL
 interface My {
     <!WRONG_MODIFIER_CONTAINING_DECLARATION!>internal<!> val x: Int
     <!WRONG_MODIFIER_CONTAINING_DECLARATION!>internal<!> val xxx: Int
diff --git a/compiler/testData/diagnostics/tests/modifiers/modifierOnParameterInFunctionType.fir.kt b/compiler/testData/diagnostics/tests/modifiers/modifierOnParameterInFunctionType.fir.kt
index eef65241792..ebcab0ac6d5 100644
--- a/compiler/testData/diagnostics/tests/modifiers/modifierOnParameterInFunctionType.fir.kt
+++ b/compiler/testData/diagnostics/tests/modifiers/modifierOnParameterInFunctionType.fir.kt
@@ -2,11 +2,11 @@
 
 fun f(vararg x: Int) {}
 
-val inVal: (vararg x: Int)->Unit = {}
+val inVal: (<!WRONG_MODIFIER_CONTAINING_DECLARATION!>vararg<!> x: Int)->Unit = {}
 
-fun inParam(fn: (vararg x: Int)->Unit) {}
+fun inParam(fn: (<!WRONG_MODIFIER_CONTAINING_DECLARATION!>vararg<!> x: Int)->Unit) {}
 
-fun inParamNested(fn1: (fn2: (vararg n: Int)->Unit)->Unit) {}
+fun inParamNested(fn1: (fn2: (<!WRONG_MODIFIER_CONTAINING_DECLARATION!>vararg<!> n: Int)->Unit)->Unit) {}
 
 fun inReturn(): (vararg x: Int)->Unit = {}
 
@@ -16,7 +16,7 @@ class A : (vararg Int)->Unit {
     }
 
     val prop: (vararg x: Int)->Unit
-        get(): (vararg x: Int)->Unit = {}
+        get(): (<!WRONG_MODIFIER_CONTAINING_DECLARATION, WRONG_MODIFIER_CONTAINING_DECLARATION!>vararg<!> x: Int)->Unit = {}
 }
 
 val allProhibited: (<!REDUNDANT_MODIFIER, WRONG_MODIFIER_TARGET!>abstract<!>
@@ -44,7 +44,7 @@ val allProhibited: (<!REDUNDANT_MODIFIER, WRONG_MODIFIER_TARGET!>abstract<!>
                     <!WRONG_MODIFIER_TARGET!>reified<!>
                     <!INCOMPATIBLE_MODIFIERS!>sealed<!>
                     <!WRONG_MODIFIER_TARGET!>tailrec<!>
-                    vararg
+                    <!WRONG_MODIFIER_CONTAINING_DECLARATION!>vararg<!>
 
                     x: Int)->Unit = {}
 
diff --git a/compiler/testData/diagnostics/tests/modifiers/privateInInterface.fir.kt b/compiler/testData/diagnostics/tests/modifiers/privateInInterface.fir.kt
deleted file mode 100644
index ab643640a12..00000000000
--- a/compiler/testData/diagnostics/tests/modifiers/privateInInterface.fir.kt
+++ /dev/null
@@ -1,12 +0,0 @@
-interface My {
-    <!PRIVATE_PROPERTY_IN_INTERFACE!>private<!> val x: Int
-    <!INCOMPATIBLE_MODIFIERS!>private<!> <!INCOMPATIBLE_MODIFIERS!>abstract<!> val xx: Int
-    private val xxx: Int
-        get() = 0
-    final val y: Int
-    final val yy: Int
-        get() = 1
-    <!PRIVATE_FUNCTION_WITH_NO_BODY!>private<!> fun foo(): Int
-    // ok
-    private fun bar() = 42
-}
diff --git a/compiler/testData/diagnostics/tests/modifiers/privateInInterface.kt b/compiler/testData/diagnostics/tests/modifiers/privateInInterface.kt
index 2201fb23911..ea5095b3525 100644
--- a/compiler/testData/diagnostics/tests/modifiers/privateInInterface.kt
+++ b/compiler/testData/diagnostics/tests/modifiers/privateInInterface.kt
@@ -1,3 +1,4 @@
+// FIR_IDENTICAL
 interface My {
     <!PRIVATE_PROPERTY_IN_INTERFACE!>private<!> val x: Int
     <!INCOMPATIBLE_MODIFIERS!>private<!> <!INCOMPATIBLE_MODIFIERS!>abstract<!> val xx: Int
diff --git a/compiler/testData/diagnostics/tests/modifiers/protected.fir.kt b/compiler/testData/diagnostics/tests/modifiers/protected.fir.kt
deleted file mode 100644
index 203b968c732..00000000000
--- a/compiler/testData/diagnostics/tests/modifiers/protected.fir.kt
+++ /dev/null
@@ -1,21 +0,0 @@
-class My(protected val x: Int) {
-    class Her(protected val x: Int)
-
-    inner class Its(protected val x: Int)
-}
-
-object Your {
-    protected fun foo() = 3
-}
-
-annotation class His(protected val x: Int)
-
-enum class Our(protected val x: Int) {
-    FIRST(42) {
-        protected fun foo() = 13
-    }
-}
-
-interface Their {
-    protected fun foo() = 7
-}
\ No newline at end of file
diff --git a/compiler/testData/diagnostics/tests/modifiers/protected.kt b/compiler/testData/diagnostics/tests/modifiers/protected.kt
index 97b39c3169a..3edc611ba4c 100644
--- a/compiler/testData/diagnostics/tests/modifiers/protected.kt
+++ b/compiler/testData/diagnostics/tests/modifiers/protected.kt
@@ -1,3 +1,4 @@
+// FIR_IDENTICAL
 class My(protected val x: Int) {
     class Her(protected val x: Int)
 
diff --git a/compiler/testData/diagnostics/tests/scopes/kt1822.fir.kt b/compiler/testData/diagnostics/tests/scopes/kt1822.fir.kt
index ed18d966a00..3b9ba501690 100644
--- a/compiler/testData/diagnostics/tests/scopes/kt1822.fir.kt
+++ b/compiler/testData/diagnostics/tests/scopes/kt1822.fir.kt
@@ -6,7 +6,7 @@ open class C {
 }
 
 interface T {
-    protected fun foo() {}
+    <!WRONG_MODIFIER_CONTAINING_DECLARATION!>protected<!> fun foo() {}
 }
 
 class G : C(), T {
@@ -18,7 +18,7 @@ open class A {
 }
 
 interface B {
-    protected fun foo() {}
+    <!WRONG_MODIFIER_CONTAINING_DECLARATION!>protected<!> fun foo() {}
 }
 
 interface D {
@@ -27,4 +27,4 @@ interface D {
 
 class E : A(), B, D {
     override fun foo() {}
-}
\ No newline at end of file
+}
diff --git a/compiler/testData/diagnostics/tests/scopes/visibility.fir.kt b/compiler/testData/diagnostics/tests/scopes/visibility.fir.kt
index 734a85b1bed..c9c1589337a 100644
--- a/compiler/testData/diagnostics/tests/scopes/visibility.fir.kt
+++ b/compiler/testData/diagnostics/tests/scopes/visibility.fir.kt
@@ -3,8 +3,8 @@
 //FILE:a.kt
 package test_visibility
 
-protected class ProtectedClass
-protected interface ProtectedTrait
+<!WRONG_MODIFIER_CONTAINING_DECLARATION!>protected<!> class ProtectedClass
+<!WRONG_MODIFIER_CONTAINING_DECLARATION!>protected<!> interface ProtectedTrait
 
 <!WRONG_MODIFIER_TARGET!>protected<!> val protected_val : Int = 4
 <!WRONG_MODIFIER_TARGET!>protected<!> fun protected_fun() {}
diff --git a/compiler/testData/diagnostics/tests/varargs/varargInSetter.fir.kt b/compiler/testData/diagnostics/tests/varargs/varargInSetter.fir.kt
index 56b49f5cd9c..8dff30b3190 100644
--- a/compiler/testData/diagnostics/tests/varargs/varargInSetter.fir.kt
+++ b/compiler/testData/diagnostics/tests/varargs/varargInSetter.fir.kt
@@ -1,6 +1,6 @@
 class My {
     var x: String = ""
-        set(vararg value) {
+        set(<!WRONG_MODIFIER_CONTAINING_DECLARATION!>vararg<!> value) {
             x = <!ASSIGNMENT_TYPE_MISMATCH!>value<!>
         }
 }
diff --git a/compiler/testData/diagnostics/tests/variance/Visibility.fir.kt b/compiler/testData/diagnostics/tests/variance/Visibility.fir.kt
deleted file mode 100644
index 9079ddad14d..00000000000
--- a/compiler/testData/diagnostics/tests/variance/Visibility.fir.kt
+++ /dev/null
@@ -1,20 +0,0 @@
-interface Test<in I, out O> {
-    val internal_val: <!TYPE_VARIANCE_CONFLICT!>I<!>
-    public val public_val: <!TYPE_VARIANCE_CONFLICT!>I<!>
-    protected val protected_val: <!TYPE_VARIANCE_CONFLICT!>I<!>
-    <!PRIVATE_PROPERTY_IN_INTERFACE!>private<!> val private_val: I
-
-    var interlan_private_set: <!TYPE_VARIANCE_CONFLICT!>O<!>
-        <!PRIVATE_SETTER_FOR_ABSTRACT_PROPERTY!>private<!> set
-    public var public_private_set: <!TYPE_VARIANCE_CONFLICT!>O<!>
-        <!PRIVATE_SETTER_FOR_ABSTRACT_PROPERTY!>private<!> set
-    protected var protected_private_set: <!TYPE_VARIANCE_CONFLICT!>O<!>
-        <!PRIVATE_SETTER_FOR_ABSTRACT_PROPERTY!>private<!> set
-    <!PRIVATE_PROPERTY_IN_INTERFACE!>private<!> var private_private_set: O
-        private set
-
-    fun internal_fun(i: <!TYPE_VARIANCE_CONFLICT!>O<!>) : <!TYPE_VARIANCE_CONFLICT!>I<!>
-    public fun public_fun(i: <!TYPE_VARIANCE_CONFLICT!>O<!>) : <!TYPE_VARIANCE_CONFLICT!>I<!>
-    protected fun protected_fun(i: <!TYPE_VARIANCE_CONFLICT!>O<!>) : <!TYPE_VARIANCE_CONFLICT!>I<!>
-    <!PRIVATE_FUNCTION_WITH_NO_BODY!>private<!> fun private_fun(i: O) : I
-}
diff --git a/compiler/testData/diagnostics/tests/variance/Visibility.kt b/compiler/testData/diagnostics/tests/variance/Visibility.kt
index 4c7fa06385a..15792ecb19d 100644
--- a/compiler/testData/diagnostics/tests/variance/Visibility.kt
+++ b/compiler/testData/diagnostics/tests/variance/Visibility.kt
@@ -1,3 +1,4 @@
+// FIR_IDENTICAL
 interface Test<in I, out O> {
     val internal_val: <!TYPE_VARIANCE_CONFLICT!>I<!>
     public val public_val: <!TYPE_VARIANCE_CONFLICT!>I<!>
diff --git a/idea/idea-frontend-fir/src/org/jetbrains/kotlin/idea/frontend/api/fir/diagnostics/KtFirDataClassConverters.kt b/idea/idea-frontend-fir/src/org/jetbrains/kotlin/idea/frontend/api/fir/diagnostics/KtFirDataClassConverters.kt
index 4ec567ed5bd..28138755d2b 100644
--- a/idea/idea-frontend-fir/src/org/jetbrains/kotlin/idea/frontend/api/fir/diagnostics/KtFirDataClassConverters.kt
+++ b/idea/idea-frontend-fir/src/org/jetbrains/kotlin/idea/frontend/api/fir/diagnostics/KtFirDataClassConverters.kt
@@ -1083,6 +1083,22 @@ internal val KT_DIAGNOSTIC_CONVERTER = KtDiagnosticConverterBuilder.buildConvert
             token,
         )
     }
+    add(FirErrors.WRONG_MODIFIER_CONTAINING_DECLARATION) { firDiagnostic ->
+        WrongModifierContainingDeclarationImpl(
+            firDiagnostic.a,
+            firDiagnostic.b,
+            firDiagnostic as FirPsiDiagnostic,
+            token,
+        )
+    }
+    add(FirErrors.DEPRECATED_MODIFIER_CONTAINING_DECLARATION) { firDiagnostic ->
+        DeprecatedModifierContainingDeclarationImpl(
+            firDiagnostic.a,
+            firDiagnostic.b,
+            firDiagnostic as FirPsiDiagnostic,
+            token,
+        )
+    }
     add(FirErrors.INLINE_CLASS_NOT_TOP_LEVEL) { firDiagnostic ->
         InlineClassNotTopLevelImpl(
             firDiagnostic as FirPsiDiagnostic,
diff --git a/idea/idea-frontend-fir/src/org/jetbrains/kotlin/idea/frontend/api/fir/diagnostics/KtFirDiagnostics.kt b/idea/idea-frontend-fir/src/org/jetbrains/kotlin/idea/frontend/api/fir/diagnostics/KtFirDiagnostics.kt
index 9b1c2939e99..dacb46a7361 100644
--- a/idea/idea-frontend-fir/src/org/jetbrains/kotlin/idea/frontend/api/fir/diagnostics/KtFirDiagnostics.kt
+++ b/idea/idea-frontend-fir/src/org/jetbrains/kotlin/idea/frontend/api/fir/diagnostics/KtFirDiagnostics.kt
@@ -783,6 +783,18 @@ sealed class KtFirDiagnostic<PSI : PsiElement> : KtDiagnosticWithPsi<PSI> {
         abstract val functionSymbol: KtFunctionLikeSymbol
     }
 
+    abstract class WrongModifierContainingDeclaration : KtFirDiagnostic<PsiElement>() {
+        override val diagnosticClass get() = WrongModifierContainingDeclaration::class
+        abstract val modifier: String
+        abstract val target: String
+    }
+
+    abstract class DeprecatedModifierContainingDeclaration : KtFirDiagnostic<PsiElement>() {
+        override val diagnosticClass get() = DeprecatedModifierContainingDeclaration::class
+        abstract val modifier: String
+        abstract val target: String
+    }
+
     abstract class InlineClassNotTopLevel : KtFirDiagnostic<KtDeclaration>() {
         override val diagnosticClass get() = InlineClassNotTopLevel::class
     }
diff --git a/idea/idea-frontend-fir/src/org/jetbrains/kotlin/idea/frontend/api/fir/diagnostics/KtFirDiagnosticsImpl.kt b/idea/idea-frontend-fir/src/org/jetbrains/kotlin/idea/frontend/api/fir/diagnostics/KtFirDiagnosticsImpl.kt
index d170e3fd74c..2e6aa4b72da 100644
--- a/idea/idea-frontend-fir/src/org/jetbrains/kotlin/idea/frontend/api/fir/diagnostics/KtFirDiagnosticsImpl.kt
+++ b/idea/idea-frontend-fir/src/org/jetbrains/kotlin/idea/frontend/api/fir/diagnostics/KtFirDiagnosticsImpl.kt
@@ -1243,6 +1243,24 @@ internal class InfixModifierRequiredImpl(
     override val firDiagnostic: FirPsiDiagnostic by weakRef(firDiagnostic)
 }
 
+internal class WrongModifierContainingDeclarationImpl(
+    override val modifier: String,
+    override val target: String,
+    firDiagnostic: FirPsiDiagnostic,
+    override val token: ValidityToken,
+) : KtFirDiagnostic.WrongModifierContainingDeclaration(), KtAbstractFirDiagnostic<PsiElement> {
+    override val firDiagnostic: FirPsiDiagnostic by weakRef(firDiagnostic)
+}
+
+internal class DeprecatedModifierContainingDeclarationImpl(
+    override val modifier: String,
+    override val target: String,
+    firDiagnostic: FirPsiDiagnostic,
+    override val token: ValidityToken,
+) : KtFirDiagnostic.DeprecatedModifierContainingDeclaration(), KtAbstractFirDiagnostic<PsiElement> {
+    override val firDiagnostic: FirPsiDiagnostic by weakRef(firDiagnostic)
+}
+
 internal class InlineClassNotTopLevelImpl(
     firDiagnostic: FirPsiDiagnostic,
     override val token: ValidityToken,