diff --git a/compiler/fir/checkers/src/org/jetbrains/kotlin/fir/analysis/checkers/declaration/FirConstructorInInterfaceChecker.kt b/compiler/fir/checkers/src/org/jetbrains/kotlin/fir/analysis/checkers/declaration/FirConstructorInInterfaceChecker.kt
index 65530d9fea0..0014a41ff4a 100644
--- a/compiler/fir/checkers/src/org/jetbrains/kotlin/fir/analysis/checkers/declaration/FirConstructorInInterfaceChecker.kt
+++ b/compiler/fir/checkers/src/org/jetbrains/kotlin/fir/analysis/checkers/declaration/FirConstructorInInterfaceChecker.kt
@@ -5,17 +5,17 @@
 
 package org.jetbrains.kotlin.fir.analysis.checkers.declaration
 
-import org.jetbrains.kotlin.descriptors.ClassKind
 import org.jetbrains.kotlin.fir.FirSourceElement
 import org.jetbrains.kotlin.fir.analysis.checkers.context.CheckerContext
 import org.jetbrains.kotlin.fir.analysis.diagnostics.DiagnosticReporter
 import org.jetbrains.kotlin.fir.analysis.diagnostics.FirErrors
 import org.jetbrains.kotlin.fir.analysis.diagnostics.hasPrimaryConstructor
 import org.jetbrains.kotlin.fir.declarations.FirRegularClass
+import org.jetbrains.kotlin.fir.declarations.isInterface
 
 object FirConstructorInInterfaceChecker : FirRegularClassChecker() {
     override fun check(declaration: FirRegularClass, context: CheckerContext, reporter: DiagnosticReporter) {
-        if (declaration.classKind != ClassKind.INTERFACE) {
+        if (!declaration.isInterface) {
             return
         }
 
diff --git a/compiler/fir/checkers/src/org/jetbrains/kotlin/fir/analysis/checkers/declaration/FirDelegationInInterfaceChecker.kt b/compiler/fir/checkers/src/org/jetbrains/kotlin/fir/analysis/checkers/declaration/FirDelegationInInterfaceChecker.kt
index 8584567b06a..a30619b0675 100644
--- a/compiler/fir/checkers/src/org/jetbrains/kotlin/fir/analysis/checkers/declaration/FirDelegationInInterfaceChecker.kt
+++ b/compiler/fir/checkers/src/org/jetbrains/kotlin/fir/analysis/checkers/declaration/FirDelegationInInterfaceChecker.kt
@@ -6,16 +6,16 @@
 package org.jetbrains.kotlin.fir.analysis.checkers.declaration
 
 import org.jetbrains.kotlin.KtNodeTypes
-import org.jetbrains.kotlin.descriptors.ClassKind
 import org.jetbrains.kotlin.fir.FirSourceElement
 import org.jetbrains.kotlin.fir.analysis.checkers.context.CheckerContext
 import org.jetbrains.kotlin.fir.analysis.diagnostics.DiagnosticReporter
 import org.jetbrains.kotlin.fir.analysis.diagnostics.FirErrors
 import org.jetbrains.kotlin.fir.declarations.FirRegularClass
+import org.jetbrains.kotlin.fir.declarations.isInterface
 
 object FirDelegationInInterfaceChecker : FirRegularClassChecker() {
     override fun check(declaration: FirRegularClass, context: CheckerContext, reporter: DiagnosticReporter) {
-        if (declaration.classKind != ClassKind.INTERFACE) {
+        if (!declaration.isInterface) {
             return
         }
 
diff --git a/compiler/fir/checkers/src/org/jetbrains/kotlin/fir/analysis/checkers/declaration/FirDelegationSuperCallInEnumConstructorChecker.kt b/compiler/fir/checkers/src/org/jetbrains/kotlin/fir/analysis/checkers/declaration/FirDelegationSuperCallInEnumConstructorChecker.kt
index a8da964e437..c4bab19cbda 100644
--- a/compiler/fir/checkers/src/org/jetbrains/kotlin/fir/analysis/checkers/declaration/FirDelegationSuperCallInEnumConstructorChecker.kt
+++ b/compiler/fir/checkers/src/org/jetbrains/kotlin/fir/analysis/checkers/declaration/FirDelegationSuperCallInEnumConstructorChecker.kt
@@ -5,7 +5,6 @@
 
 package org.jetbrains.kotlin.fir.analysis.checkers.declaration
 
-import org.jetbrains.kotlin.descriptors.ClassKind
 import org.jetbrains.kotlin.fir.FirFakeSourceElementKind
 import org.jetbrains.kotlin.fir.FirSourceElement
 import org.jetbrains.kotlin.fir.analysis.checkers.context.CheckerContext
@@ -13,10 +12,11 @@ import org.jetbrains.kotlin.fir.analysis.diagnostics.DiagnosticReporter
 import org.jetbrains.kotlin.fir.analysis.diagnostics.FirErrors
 import org.jetbrains.kotlin.fir.declarations.FirConstructor
 import org.jetbrains.kotlin.fir.declarations.FirRegularClass
+import org.jetbrains.kotlin.fir.declarations.isEnumClass
 
 object FirDelegationSuperCallInEnumConstructorChecker : FirRegularClassChecker() {
     override fun check(declaration: FirRegularClass, context: CheckerContext, reporter: DiagnosticReporter) {
-        if (declaration.classKind != ClassKind.ENUM_CLASS) {
+        if (!declaration.isEnumClass) {
             return
         }
 
diff --git a/compiler/fir/checkers/src/org/jetbrains/kotlin/fir/analysis/checkers/declaration/FirEnumClassSimpleChecker.kt b/compiler/fir/checkers/src/org/jetbrains/kotlin/fir/analysis/checkers/declaration/FirEnumClassSimpleChecker.kt
index cbac351329f..5670b872be6 100644
--- a/compiler/fir/checkers/src/org/jetbrains/kotlin/fir/analysis/checkers/declaration/FirEnumClassSimpleChecker.kt
+++ b/compiler/fir/checkers/src/org/jetbrains/kotlin/fir/analysis/checkers/declaration/FirEnumClassSimpleChecker.kt
@@ -5,17 +5,17 @@
 
 package org.jetbrains.kotlin.fir.analysis.checkers.declaration
 
-import org.jetbrains.kotlin.descriptors.ClassKind
 import org.jetbrains.kotlin.fir.FirSourceElement
 import org.jetbrains.kotlin.fir.analysis.checkers.context.CheckerContext
 import org.jetbrains.kotlin.fir.analysis.checkers.findNonInterfaceSupertype
 import org.jetbrains.kotlin.fir.analysis.diagnostics.DiagnosticReporter
 import org.jetbrains.kotlin.fir.analysis.diagnostics.FirErrors
 import org.jetbrains.kotlin.fir.declarations.FirRegularClass
+import org.jetbrains.kotlin.fir.declarations.isEnumClass
 
 object FirEnumClassSimpleChecker : FirRegularClassChecker() {
     override fun check(declaration: FirRegularClass, context: CheckerContext, reporter: DiagnosticReporter) {
-        if (declaration.classKind != ClassKind.ENUM_CLASS) {
+        if (!declaration.isEnumClass) {
             return
         }
 
diff --git a/compiler/fir/checkers/src/org/jetbrains/kotlin/fir/analysis/checkers/declaration/FirInterfaceWithSuperclassChecker.kt b/compiler/fir/checkers/src/org/jetbrains/kotlin/fir/analysis/checkers/declaration/FirInterfaceWithSuperclassChecker.kt
index ebd188f3f44..24e69261a20 100644
--- a/compiler/fir/checkers/src/org/jetbrains/kotlin/fir/analysis/checkers/declaration/FirInterfaceWithSuperclassChecker.kt
+++ b/compiler/fir/checkers/src/org/jetbrains/kotlin/fir/analysis/checkers/declaration/FirInterfaceWithSuperclassChecker.kt
@@ -5,17 +5,17 @@
 
 package org.jetbrains.kotlin.fir.analysis.checkers.declaration
 
-import org.jetbrains.kotlin.descriptors.ClassKind
 import org.jetbrains.kotlin.fir.FirSourceElement
 import org.jetbrains.kotlin.fir.analysis.checkers.context.CheckerContext
 import org.jetbrains.kotlin.fir.analysis.checkers.findNonInterfaceSupertype
 import org.jetbrains.kotlin.fir.analysis.diagnostics.DiagnosticReporter
 import org.jetbrains.kotlin.fir.analysis.diagnostics.FirErrors
 import org.jetbrains.kotlin.fir.declarations.FirRegularClass
+import org.jetbrains.kotlin.fir.declarations.isInterface
 
 object FirInterfaceWithSuperclassChecker : FirRegularClassChecker() {
     override fun check(declaration: FirRegularClass, context: CheckerContext, reporter: DiagnosticReporter) {
-        if (declaration.classKind != ClassKind.INTERFACE) {
+        if (!declaration.isInterface) {
             return
         }
 
diff --git a/compiler/fir/checkers/src/org/jetbrains/kotlin/fir/analysis/checkers/declaration/FirMethodOfAnyImplementedInInterfaceChecker.kt b/compiler/fir/checkers/src/org/jetbrains/kotlin/fir/analysis/checkers/declaration/FirMethodOfAnyImplementedInInterfaceChecker.kt
index f52c3be8243..fcc41268fb6 100644
--- a/compiler/fir/checkers/src/org/jetbrains/kotlin/fir/analysis/checkers/declaration/FirMethodOfAnyImplementedInInterfaceChecker.kt
+++ b/compiler/fir/checkers/src/org/jetbrains/kotlin/fir/analysis/checkers/declaration/FirMethodOfAnyImplementedInInterfaceChecker.kt
@@ -5,7 +5,6 @@
 
 package org.jetbrains.kotlin.fir.analysis.checkers.declaration
 
-import org.jetbrains.kotlin.descriptors.ClassKind
 import org.jetbrains.kotlin.fir.FirSourceElement
 import org.jetbrains.kotlin.fir.analysis.checkers.FirDeclarationInspector
 import org.jetbrains.kotlin.fir.analysis.checkers.FirDeclarationPresenter
@@ -57,7 +56,7 @@ object FirMethodOfAnyImplementedInInterfaceChecker : FirRegularClassChecker(), F
     }
 
     override fun check(declaration: FirRegularClass, context: CheckerContext, reporter: DiagnosticReporter) {
-        if (declaration.classKind != ClassKind.INTERFACE) {
+        if (!declaration.isInterface) {
             return
         }
 
diff --git a/compiler/fir/checkers/src/org/jetbrains/kotlin/fir/analysis/checkers/declaration/FirSupertypeInitializedInInterfaceChecker.kt b/compiler/fir/checkers/src/org/jetbrains/kotlin/fir/analysis/checkers/declaration/FirSupertypeInitializedInInterfaceChecker.kt
index 7478d2d5665..3e4c655da9e 100644
--- a/compiler/fir/checkers/src/org/jetbrains/kotlin/fir/analysis/checkers/declaration/FirSupertypeInitializedInInterfaceChecker.kt
+++ b/compiler/fir/checkers/src/org/jetbrains/kotlin/fir/analysis/checkers/declaration/FirSupertypeInitializedInInterfaceChecker.kt
@@ -6,16 +6,16 @@
 package org.jetbrains.kotlin.fir.analysis.checkers.declaration
 
 import org.jetbrains.kotlin.KtNodeTypes
-import org.jetbrains.kotlin.descriptors.ClassKind
 import org.jetbrains.kotlin.fir.FirSourceElement
 import org.jetbrains.kotlin.fir.analysis.checkers.context.CheckerContext
 import org.jetbrains.kotlin.fir.analysis.diagnostics.DiagnosticReporter
 import org.jetbrains.kotlin.fir.analysis.diagnostics.FirErrors
 import org.jetbrains.kotlin.fir.declarations.FirRegularClass
+import org.jetbrains.kotlin.fir.declarations.isInterface
 
 object FirSupertypeInitializedInInterfaceChecker : FirRegularClassChecker() {
     override fun check(declaration: FirRegularClass, context: CheckerContext, reporter: DiagnosticReporter) {
-        if (declaration.classKind != ClassKind.INTERFACE) {
+        if (!declaration.isInterface) {
             return
         }
 
diff --git a/compiler/fir/checkers/src/org/jetbrains/kotlin/fir/analysis/checkers/declaration/FirSupertypeInitializedWithoutPrimaryConstructor.kt b/compiler/fir/checkers/src/org/jetbrains/kotlin/fir/analysis/checkers/declaration/FirSupertypeInitializedWithoutPrimaryConstructor.kt
index 9e31f99a1d6..fa9782af05e 100644
--- a/compiler/fir/checkers/src/org/jetbrains/kotlin/fir/analysis/checkers/declaration/FirSupertypeInitializedWithoutPrimaryConstructor.kt
+++ b/compiler/fir/checkers/src/org/jetbrains/kotlin/fir/analysis/checkers/declaration/FirSupertypeInitializedWithoutPrimaryConstructor.kt
@@ -6,17 +6,17 @@
 package org.jetbrains.kotlin.fir.analysis.checkers.declaration
 
 import org.jetbrains.kotlin.KtNodeTypes
-import org.jetbrains.kotlin.descriptors.ClassKind
 import org.jetbrains.kotlin.fir.FirSourceElement
 import org.jetbrains.kotlin.fir.analysis.checkers.context.CheckerContext
 import org.jetbrains.kotlin.fir.analysis.diagnostics.DiagnosticReporter
 import org.jetbrains.kotlin.fir.analysis.diagnostics.FirErrors
 import org.jetbrains.kotlin.fir.declarations.FirConstructor
 import org.jetbrains.kotlin.fir.declarations.FirRegularClass
+import org.jetbrains.kotlin.fir.declarations.isInterface
 
 object FirSupertypeInitializedWithoutPrimaryConstructor : FirRegularClassChecker() {
     override fun check(declaration: FirRegularClass, context: CheckerContext, reporter: DiagnosticReporter) {
-        if (declaration.classKind == ClassKind.INTERFACE) {
+        if (declaration.isInterface) {
             return
         }