diff --git a/compiler/fir/analysis-tests/testData/resolve/diagnostics/conflictingOverloads.kt b/compiler/fir/analysis-tests/testData/resolve/diagnostics/conflictingOverloads.kt
index dde780a5ce9..249d4fba563 100644
--- a/compiler/fir/analysis-tests/testData/resolve/diagnostics/conflictingOverloads.kt
+++ b/compiler/fir/analysis-tests/testData/resolve/diagnostics/conflictingOverloads.kt
@@ -8,17 +8,17 @@ fun test() {}
 
 fun test(z: Int, c: Char) {}
 
-<!REDECLARATION!>open class A {
+open class <!PACKAGE_OR_CLASSIFIER_REDECLARATION!>A<!> {
     open fun rest(s: String) {}
 
     open val u = 20
-}<!>
+}
 
-<!REDECLARATION!>class A {
+class <!PACKAGE_OR_CLASSIFIER_REDECLARATION!>A<!> {
 
-}<!>
+}
 
-<!REDECLARATION!>class B : <!FINAL_SUPERTYPE, SUPERTYPE_NOT_INITIALIZED!>A<!> {
+class <!PACKAGE_OR_CLASSIFIER_REDECLARATION!>B<!> : <!FINAL_SUPERTYPE, SUPERTYPE_NOT_INITIALIZED!>A<!> {
     <!CONFLICTING_OVERLOADS!><!NOTHING_TO_OVERRIDE!>override<!> fun rest(s: String)<!> {}
 
     <!CONFLICTING_OVERLOADS!>fun rest(s: String)<!> {}
@@ -26,17 +26,17 @@ fun test(z: Int, c: Char) {}
     fun rest(l: Long) {}
 
     <!NOTHING_TO_OVERRIDE!>override<!> val u = 310
-}<!>
+}
 
-<!REDECLARATION!>interface B<!>
+interface <!PACKAGE_OR_CLASSIFIER_REDECLARATION!>B<!>
 
-<!REDECLARATION!>enum class B<!>
+enum class <!PACKAGE_OR_CLASSIFIER_REDECLARATION!>B<!>
 
-<!REDECLARATION!>val u = 10<!>
-<!REDECLARATION!>val u = 20<!>
+val <!REDECLARATION!>u<!> = 10
+val <!REDECLARATION!>u<!> = 20
 
-<!REDECLARATION!>typealias TA = A<!>
-<!REDECLARATION!>typealias TA = B<!>
+typealias <!PACKAGE_OR_CLASSIFIER_REDECLARATION!>TA<!> = A
+typealias <!PACKAGE_OR_CLASSIFIER_REDECLARATION!>TA<!> = B
 
 typealias BA = A
 
@@ -52,7 +52,7 @@ fun lol(a: Array<Boolean>) {}
 
 class M {
     companion <!REDECLARATION!>object<!> {}
-    <!REDECLARATION!>val Companion = object : Any {}<!>
+    val <!REDECLARATION!>Companion<!> = object : Any {}
 }
 
 fun B.foo() {}
diff --git a/compiler/fir/analysis-tests/testData/resolve/diagnostics/sealedSupertype.kt b/compiler/fir/analysis-tests/testData/resolve/diagnostics/sealedSupertype.kt
index 722d2e4dfbf..57d9216714e 100644
--- a/compiler/fir/analysis-tests/testData/resolve/diagnostics/sealedSupertype.kt
+++ b/compiler/fir/analysis-tests/testData/resolve/diagnostics/sealedSupertype.kt
@@ -2,7 +2,7 @@
 
 sealed class A
 
-<!REDECLARATION!>class B : A()<!>
+class <!PACKAGE_OR_CLASSIFIER_REDECLARATION!>B<!> : A()
 
 interface C : <!INTERFACE_WITH_SUPERCLASS!>A<!>
 
@@ -30,7 +30,7 @@ sealed class P {
 
 class K : P()
 
-<!REDECLARATION!>object B<!> {
+object <!PACKAGE_OR_CLASSIFIER_REDECLARATION!>B<!> {
     class I : P()
 }
 
diff --git a/compiler/fir/analysis-tests/testData/resolve/expresssions/objectVsProperty.kt b/compiler/fir/analysis-tests/testData/resolve/expresssions/objectVsProperty.kt
index 2f741aa3133..8037deae390 100644
--- a/compiler/fir/analysis-tests/testData/resolve/expresssions/objectVsProperty.kt
+++ b/compiler/fir/analysis-tests/testData/resolve/expresssions/objectVsProperty.kt
@@ -1,6 +1,6 @@
-<!REDECLARATION!>object A<!>
+object <!REDECLARATION!>A<!>
 
-<!REDECLARATION!>val A = 10<!>
+val <!REDECLARATION!>A<!> = 10
 
 
 fun foo() = A
diff --git a/compiler/fir/analysis-tests/testData/resolve/extendedCheckers/RedundantSetterParameterTypeChecker.kt b/compiler/fir/analysis-tests/testData/resolve/extendedCheckers/RedundantSetterParameterTypeChecker.kt
index 779a40a56b3..924d58c56d9 100644
--- a/compiler/fir/analysis-tests/testData/resolve/extendedCheckers/RedundantSetterParameterTypeChecker.kt
+++ b/compiler/fir/analysis-tests/testData/resolve/extendedCheckers/RedundantSetterParameterTypeChecker.kt
@@ -2,15 +2,15 @@
 @Target(AnnotationTarget.VALUE_PARAMETER)
 annotation class Ann
 
-<!REDECLARATION!>var x: Int
+var <!REDECLARATION!>x<!>: Int
     get() = 1
-    set(@Ann private x) { }<!>
+    set(@Ann private x) { }
 
 
-<!REDECLARATION!>var x: String = ""
+var <!REDECLARATION!>x<!>: String = ""
     set(param: <!REDUNDANT_SETTER_PARAMETER_TYPE!>String<!>) {
         field = "$param "
-    }<!>
+    }
 
 class My {
     var y: Int = 1
@@ -25,4 +25,4 @@ class My {
         set(param) {
             field = !param
         }
-}
\ No newline at end of file
+}
diff --git a/compiler/fir/analysis-tests/testData/resolve/extendedCheckers/RedundantVisibilityModifierChecker.kt b/compiler/fir/analysis-tests/testData/resolve/extendedCheckers/RedundantVisibilityModifierChecker.kt
index 388747a4a71..d5de656cbb4 100644
--- a/compiler/fir/analysis-tests/testData/resolve/extendedCheckers/RedundantVisibilityModifierChecker.kt
+++ b/compiler/fir/analysis-tests/testData/resolve/extendedCheckers/RedundantVisibilityModifierChecker.kt
@@ -10,11 +10,11 @@ internal <!NOTHING_TO_INLINE!>inline<!> fun internal() {
     f()
 }
 
-<!REDECLARATION!>class C {
+class <!PACKAGE_OR_CLASSIFIER_REDECLARATION!>C<!> {
     internal val z = object {
         fun foo() = 13
     }
-}<!>
+}
 
 class Foo2<
         T1,
@@ -26,12 +26,12 @@ class Foo2<
     internal inner class B<T,T2,>
 }
 
-<!REDECLARATION!><!REDUNDANT_VISIBILITY_MODIFIER!>public<!> class C {
+<!REDUNDANT_VISIBILITY_MODIFIER!>public<!> class <!PACKAGE_OR_CLASSIFIER_REDECLARATION!>C<!> {
     <!REDUNDANT_VISIBILITY_MODIFIER!>public<!> val foo: Int = 0
 
     <!REDUNDANT_VISIBILITY_MODIFIER!>public<!> fun bar() {}
 
-}<!>
+}
 
 open class D {
     protected open fun willRemainProtected() {
diff --git a/compiler/fir/analysis-tests/testData/resolveWithStdlib/problems.kt b/compiler/fir/analysis-tests/testData/resolveWithStdlib/problems.kt
index c9b730ba127..8956e799a0f 100644
--- a/compiler/fir/analysis-tests/testData/resolveWithStdlib/problems.kt
+++ b/compiler/fir/analysis-tests/testData/resolveWithStdlib/problems.kt
@@ -13,7 +13,7 @@ fun test() {
 val Any.bar get() = "456"
 val String.bar get() = "987"
 
-<!REDECLARATION!>val t = "".bar<!>
+val <!REDECLARATION!>t<!> = "".bar
 
 val p = Pair(0, "")
 
@@ -21,4 +21,4 @@ open class Base<T>(val x: T)
 class Derived : Base<Int>(10)
 val xx = Derived().x + 1
 
-<!REDECLARATION!>val t = throw AssertionError("")<!>
\ No newline at end of file
+val <!REDECLARATION!>t<!> = throw AssertionError("")
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 64bbac125fa..0d17759b2b1 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
@@ -714,7 +714,10 @@ object DIAGNOSTICS_LIST : DiagnosticList("FirErrors") {
         val CONFLICTING_OVERLOADS by error<PsiElement>(PositioningStrategy.DECLARATION_SIGNATURE_OR_DEFAULT) {
             parameter<Collection<Symbol>>("conflictingOverloads")
         }
-        val REDECLARATION by error<PsiElement> {
+        val REDECLARATION by error<KtNamedDeclaration>(PositioningStrategy.NAME_IDENTIFIER) {
+            parameter<Collection<Symbol>>("conflictingDeclarations")
+        }
+        val PACKAGE_OR_CLASSIFIER_REDECLARATION by error<KtNamedDeclaration>(PositioningStrategy.ACTUAL_DECLARATION_NAME) {
             parameter<Collection<Symbol>>("conflictingDeclarations")
         }
         val METHOD_OF_ANY_IMPLEMENTED_IN_INTERFACE by error<PsiElement>()
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 06032f0ae9b..08e0790e39a 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
@@ -394,7 +394,8 @@ object FirErrors {
     // Redeclarations
     val MANY_COMPANION_OBJECTS by error0<KtObjectDeclaration>(SourceElementPositioningStrategies.COMPANION_OBJECT)
     val CONFLICTING_OVERLOADS by error1<PsiElement, Collection<FirBasedSymbol<*>>>(SourceElementPositioningStrategies.DECLARATION_SIGNATURE_OR_DEFAULT)
-    val REDECLARATION by error1<PsiElement, Collection<FirBasedSymbol<*>>>()
+    val REDECLARATION by error1<KtNamedDeclaration, Collection<FirBasedSymbol<*>>>(SourceElementPositioningStrategies.NAME_IDENTIFIER)
+    val PACKAGE_OR_CLASSIFIER_REDECLARATION by error1<KtNamedDeclaration, Collection<FirBasedSymbol<*>>>(SourceElementPositioningStrategies.ACTUAL_DECLARATION_NAME)
     val METHOD_OF_ANY_IMPLEMENTED_IN_INTERFACE by error0<PsiElement>()
 
     // Invalid local declarations
diff --git a/compiler/fir/checkers/src/org/jetbrains/kotlin/fir/analysis/checkers/declaration/FirConflictsChecker.kt b/compiler/fir/checkers/src/org/jetbrains/kotlin/fir/analysis/checkers/declaration/FirConflictsChecker.kt
index 85d135b8c5d..9fce7229be8 100644
--- a/compiler/fir/checkers/src/org/jetbrains/kotlin/fir/analysis/checkers/declaration/FirConflictsChecker.kt
+++ b/compiler/fir/checkers/src/org/jetbrains/kotlin/fir/analysis/checkers/declaration/FirConflictsChecker.kt
@@ -5,15 +5,21 @@
 
 package org.jetbrains.kotlin.fir.analysis.checkers.declaration
 
+import org.jetbrains.kotlin.descriptors.ClassKind
+import org.jetbrains.kotlin.diagnostics.PositioningStrategies
 import org.jetbrains.kotlin.fir.*
 import org.jetbrains.kotlin.fir.analysis.checkers.FirDeclarationInspector
 import org.jetbrains.kotlin.fir.analysis.checkers.FirDeclarationPresenter
 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.SourceElementPositioningStrategies
 import org.jetbrains.kotlin.fir.analysis.diagnostics.reportOn
 import org.jetbrains.kotlin.fir.declarations.*
+import org.jetbrains.kotlin.fir.declarations.utils.isCompanion
+import org.jetbrains.kotlin.fir.declarations.utils.isInner
 import org.jetbrains.kotlin.fir.resolve.firProvider
+import org.jetbrains.kotlin.fir.resolve.getOuterClass
 import org.jetbrains.kotlin.fir.scopes.PACKAGE_MEMBER
 import org.jetbrains.kotlin.fir.scopes.impl.FirPackageMemberScope
 import org.jetbrains.kotlin.fir.symbols.FirBasedSymbol
@@ -21,9 +27,13 @@ import org.jetbrains.kotlin.fir.symbols.SymbolInternals
 import org.jetbrains.kotlin.fir.symbols.ensureResolved
 import org.jetbrains.kotlin.fir.symbols.impl.FirCallableSymbol
 import org.jetbrains.kotlin.fir.symbols.impl.FirClassLikeSymbol
+import org.jetbrains.kotlin.fir.symbols.impl.FirClassSymbol
+import org.jetbrains.kotlin.fir.symbols.impl.FirRegularClassSymbol
+import org.jetbrains.kotlin.fir.util.ListMultimap
 import org.jetbrains.kotlin.fir.visitors.FirVisitorVoid
 import org.jetbrains.kotlin.name.ClassId
 import org.jetbrains.kotlin.name.Name
+import org.jetbrains.kotlin.name.SpecialNames.UNDERSCORE_FOR_UNUSED_VAR
 import org.jetbrains.kotlin.utils.SmartSet
 
 object FirConflictsChecker : FirBasicDeclarationChecker() {
@@ -197,7 +207,8 @@ object FirConflictsChecker : FirBasicDeclarationChecker() {
                             }
                     }
                 }
-                else -> {}
+                else -> {
+                }
             }
             if (declarationName != null) {
                 session.lookupTracker?.recordLookup(
@@ -216,14 +227,25 @@ object FirConflictsChecker : FirBasicDeclarationChecker() {
             else -> return
         }
 
-        inspector.declarationConflictingSymbols.forEach { (declaration, symbols) ->
-            when {
-                symbols.isEmpty() -> {}
-                declaration is FirSimpleFunction || declaration is FirConstructor -> {
-                    reporter.reportOn(declaration.source, FirErrors.CONFLICTING_OVERLOADS, symbols, context)
-                }
-                else -> {
-                    reporter.reportOn(declaration.source, FirErrors.REDECLARATION, symbols, context)
+        inspector.declarationConflictingSymbols.forEach { (conflictingDeclaration, symbols) ->
+            val source = conflictingDeclaration.source
+            if (source != null && symbols.isNotEmpty()) {
+                when (conflictingDeclaration) {
+                    is FirSimpleFunction,
+                    is FirConstructor -> {
+                        reporter.reportOn(source, FirErrors.CONFLICTING_OVERLOADS, symbols, context)
+                    }
+                    else -> {
+                        val factory = if (conflictingDeclaration is FirClassLikeDeclaration &&
+                            getOuterClass(conflictingDeclaration, context.session) == null &&
+                            symbols.any { it is FirClassLikeSymbol<*> }
+                        ) {
+                            FirErrors.PACKAGE_OR_CLASSIFIER_REDECLARATION
+                        } else {
+                            FirErrors.REDECLARATION
+                        }
+                        reporter.reportOn(source, factory, symbols, context)
+                    }
                 }
             }
         }
diff --git a/compiler/fir/checkers/src/org/jetbrains/kotlin/fir/analysis/diagnostics/LightTreePositioningStrategies.kt b/compiler/fir/checkers/src/org/jetbrains/kotlin/fir/analysis/diagnostics/LightTreePositioningStrategies.kt
index 1f9b31fa3a8..88970b4b6db 100644
--- a/compiler/fir/checkers/src/org/jetbrains/kotlin/fir/analysis/diagnostics/LightTreePositioningStrategies.kt
+++ b/compiler/fir/checkers/src/org/jetbrains/kotlin/fir/analysis/diagnostics/LightTreePositioningStrategies.kt
@@ -187,6 +187,21 @@ object LightTreePositioningStrategies {
         }
     }
 
+    val ACTUAL_DECLARATION_NAME: LightTreePositioningStrategy = object : LightTreePositioningStrategy() {
+        override fun mark(
+            node: LighterASTNode,
+            startOffset: Int,
+            endOffset: Int,
+            tree: FlyweightCapableTreeStructure<LighterASTNode>
+        ): List<TextRange> {
+            val nameIdentifier = tree.nameIdentifier(node)
+            if (nameIdentifier != null) {
+                return markElement(nameIdentifier, startOffset, endOffset, tree, node)
+            }
+            return DEFAULT.mark(node, startOffset, endOffset, tree)
+        }
+    }
+
     val DECLARATION_SIGNATURE: LightTreePositioningStrategy = object : LightTreePositioningStrategy() {
         override fun mark(
             node: LighterASTNode,
@@ -725,7 +740,7 @@ object LightTreePositioningStrategies {
             if (node.tokenType == KtNodeTypes.LABEL_QUALIFIER) {
                 return super.mark(node, startOffset, endOffset - 1, tree)
             }
-            return super.mark(node, startOffset, endOffset, tree)
+            return DEFAULT.mark(node, startOffset, endOffset, tree)
         }
     }
 
diff --git a/compiler/fir/checkers/src/org/jetbrains/kotlin/fir/analysis/diagnostics/SourceElementPositioningStrategies.kt b/compiler/fir/checkers/src/org/jetbrains/kotlin/fir/analysis/diagnostics/SourceElementPositioningStrategies.kt
index 9ba5f9e3ac4..3a25bc1b7cc 100644
--- a/compiler/fir/checkers/src/org/jetbrains/kotlin/fir/analysis/diagnostics/SourceElementPositioningStrategies.kt
+++ b/compiler/fir/checkers/src/org/jetbrains/kotlin/fir/analysis/diagnostics/SourceElementPositioningStrategies.kt
@@ -278,8 +278,12 @@ object SourceElementPositioningStrategies {
         FirPsiPositioningStrategies.UNREACHABLE_CODE
     )
 
+    val ACTUAL_DECLARATION_NAME = SourceElementPositioningStrategy(
+        LightTreePositioningStrategies.ACTUAL_DECLARATION_NAME,
+        PositioningStrategies.ACTUAL_DECLARATION_NAME
+    )
+
     // TODO
-    val ACTUAL_DECLARATION_NAME = DEFAULT
     val INCOMPATIBLE_DECLARATION = DEFAULT
 
     val NOT_SUPPORTED_IN_INLINE_MOST_RELEVANT = SourceElementPositioningStrategy(
diff --git a/compiler/fir/resolve/src/org/jetbrains/kotlin/fir/resolve/ResolveUtils.kt b/compiler/fir/resolve/src/org/jetbrains/kotlin/fir/resolve/ResolveUtils.kt
index edde64654f3..7a6e3ef49ca 100644
--- a/compiler/fir/resolve/src/org/jetbrains/kotlin/fir/resolve/ResolveUtils.kt
+++ b/compiler/fir/resolve/src/org/jetbrains/kotlin/fir/resolve/ResolveUtils.kt
@@ -502,7 +502,7 @@ fun getOuterClassAndActualTypeParametersCount(klass: FirRegularClass, session: F
     return Pair(outerClass, result)
 }
 
-fun getOuterClass(klass: FirRegularClass, session: FirSession): FirRegularClass? {
+fun getOuterClass(klass: FirClassLikeDeclaration, session: FirSession): FirRegularClass? {
     val classId = klass.symbol.classId
     val parentId = classId.relativeClassName.parent()
     if (!parentId.isRoot) {
diff --git a/compiler/testData/cli/jvm/firMultiplatformCompilationWithError.out b/compiler/testData/cli/jvm/firMultiplatformCompilationWithError.out
index 9794674e865..2805fee94f1 100644
--- a/compiler/testData/cli/jvm/firMultiplatformCompilationWithError.out
+++ b/compiler/testData/cli/jvm/firMultiplatformCompilationWithError.out
@@ -11,10 +11,10 @@ compiler or generated code. Use it at your own risk!
 warning: ATTENTION!
  This build uses in-dev FIR:
   -Xuse-fir
-compiler/testData/cli/jvm/firMultiplatformCompilationWithError/jvm.kt:1:1: error: actual class 'A' has no corresponding members for expected class members:
+compiler/testData/cli/jvm/firMultiplatformCompilationWithError/jvm.kt:1:18: error: actual class 'A' has no corresponding members for expected class members:
 
     /A.foo
 
 actual interface A
-^
+                 ^
 COMPILATION_ERROR
diff --git a/compiler/testData/diagnostics/tests/classObjects/classObjectRedeclaration.fir.kt b/compiler/testData/diagnostics/tests/classObjects/classObjectRedeclaration.fir.kt
deleted file mode 100644
index 1136f288fc8..00000000000
--- a/compiler/testData/diagnostics/tests/classObjects/classObjectRedeclaration.fir.kt
+++ /dev/null
@@ -1,20 +0,0 @@
-// !DIAGNOSTICS: -DUPLICATE_CLASS_NAMES
-package test
-
-class A {
-    <!REDECLARATION!>object Companion<!>
-
-    companion <!REDECLARATION!>object<!>
-}
-
-class B {
-    companion <!REDECLARATION!>object Named<!>
-
-    <!REDECLARATION!>object Named<!>
-}
-
-class C {
-    <!REDECLARATION!>class Named<!>
-
-    companion <!REDECLARATION!>object Named<!>
-}
\ No newline at end of file
diff --git a/compiler/testData/diagnostics/tests/classObjects/classObjectRedeclaration.kt b/compiler/testData/diagnostics/tests/classObjects/classObjectRedeclaration.kt
index 2e688e71480..1e360f98ebb 100644
--- a/compiler/testData/diagnostics/tests/classObjects/classObjectRedeclaration.kt
+++ b/compiler/testData/diagnostics/tests/classObjects/classObjectRedeclaration.kt
@@ -1,3 +1,4 @@
+// FIR_IDENTICAL
 // !DIAGNOSTICS: -DUPLICATE_CLASS_NAMES
 package test
 
diff --git a/compiler/testData/diagnostics/tests/dataClasses/repeatedProperties.fir.kt b/compiler/testData/diagnostics/tests/dataClasses/repeatedProperties.fir.kt
index 01c1f9aead0..a45b44265a0 100644
--- a/compiler/testData/diagnostics/tests/dataClasses/repeatedProperties.fir.kt
+++ b/compiler/testData/diagnostics/tests/dataClasses/repeatedProperties.fir.kt
@@ -1,9 +1,9 @@
-data class A1(<!REDECLARATION!>val x: Int<!>, val y: String, <!REDECLARATION!>val x: Int<!>) {
+data class A1(val <!REDECLARATION!>x<!>: Int, val y: String, val <!REDECLARATION!>x<!>: Int) {
     val z = ""
 }
 
-data class A2(<!REDECLARATION!>val x: Int<!>, val y: String) {
-    <!REDECLARATION!>val x = ""<!>
+data class A2(val <!REDECLARATION!>x<!>: Int, val y: String) {
+    val <!REDECLARATION!>x<!> = ""
 }
 
 data class A3(<!REDECLARATION!>val<!SYNTAX!><!> :Int<!>, <!REDECLARATION!>val<!SYNTAX!><!> : Int<!>)
diff --git a/compiler/testData/diagnostics/tests/duplicateJvmSignature/specialNames/classObject.fir.kt b/compiler/testData/diagnostics/tests/duplicateJvmSignature/specialNames/classObject.fir.kt
deleted file mode 100644
index 51abf600c1a..00000000000
--- a/compiler/testData/diagnostics/tests/duplicateJvmSignature/specialNames/classObject.fir.kt
+++ /dev/null
@@ -1,5 +0,0 @@
-class C {
-    companion <!REDECLARATION!>object<!> {}
-
-    <!REDECLARATION!>val Companion = C<!>
-}
diff --git a/compiler/testData/diagnostics/tests/duplicateJvmSignature/specialNames/classObject.kt b/compiler/testData/diagnostics/tests/duplicateJvmSignature/specialNames/classObject.kt
index 7cb3dde5a54..172d1a17778 100644
--- a/compiler/testData/diagnostics/tests/duplicateJvmSignature/specialNames/classObject.kt
+++ b/compiler/testData/diagnostics/tests/duplicateJvmSignature/specialNames/classObject.kt
@@ -1,3 +1,4 @@
+// FIR_IDENTICAL
 class C {
     companion <!REDECLARATION!>object<!> {}
 
diff --git a/compiler/testData/diagnostics/tests/duplicateJvmSignature/specialNames/classObjectCopiedFieldObject.fir.kt b/compiler/testData/diagnostics/tests/duplicateJvmSignature/specialNames/classObjectCopiedFieldObject.fir.kt
index f7e865b27d5..96a551dc0ef 100644
--- a/compiler/testData/diagnostics/tests/duplicateJvmSignature/specialNames/classObjectCopiedFieldObject.fir.kt
+++ b/compiler/testData/diagnostics/tests/duplicateJvmSignature/specialNames/classObjectCopiedFieldObject.fir.kt
@@ -1,8 +1,8 @@
 class B {
-    companion <!REDECLARATION!>object A<!> {
+    companion object <!REDECLARATION!>A<!> {
     }
 
-    <!REDECLARATION!>val A = this<!>
+    val <!REDECLARATION!>A<!> = this
 }
 
 class C {
diff --git a/compiler/testData/diagnostics/tests/multiplatform/headerClass/actualClassWithDefaultValuesInAnnotationViaTypealias.fir.kt b/compiler/testData/diagnostics/tests/multiplatform/headerClass/actualClassWithDefaultValuesInAnnotationViaTypealias.fir.kt
index b61579ea250..d2a8d82dd4e 100644
--- a/compiler/testData/diagnostics/tests/multiplatform/headerClass/actualClassWithDefaultValuesInAnnotationViaTypealias.fir.kt
+++ b/compiler/testData/diagnostics/tests/multiplatform/headerClass/actualClassWithDefaultValuesInAnnotationViaTypealias.fir.kt
@@ -45,4 +45,4 @@ actual annotation class Foo5
 
 actual annotation class Foo6(val s: String = "value")
 
-<!NO_ACTUAL_CLASS_MEMBER_FOR_EXPECTED_CLASS!>actual typealias Foo7 = Bar2<!>
+actual typealias <!NO_ACTUAL_CLASS_MEMBER_FOR_EXPECTED_CLASS!>Foo7<!> = Bar2
diff --git a/compiler/testData/diagnostics/tests/multiplatform/headerClass/actualClassWithDifferentConstructors.fir.kt b/compiler/testData/diagnostics/tests/multiplatform/headerClass/actualClassWithDifferentConstructors.fir.kt
index 3affe50a99f..d0f2570445e 100644
--- a/compiler/testData/diagnostics/tests/multiplatform/headerClass/actualClassWithDifferentConstructors.fir.kt
+++ b/compiler/testData/diagnostics/tests/multiplatform/headerClass/actualClassWithDifferentConstructors.fir.kt
@@ -34,9 +34,9 @@ actual class Foo1(val s: String)
 actual class Foo2(val p: String = "value", i: Int)
 actual typealias Foo3 = JavaFoo
 
-<!NO_ACTUAL_CLASS_MEMBER_FOR_EXPECTED_CLASS!>actual class Bar1(val s: String)<!>
-<!NO_ACTUAL_CLASS_MEMBER_FOR_EXPECTED_CLASS!>actual class Bar2(val p: String = "value", i: Int)<!>
-<!NO_ACTUAL_CLASS_MEMBER_FOR_EXPECTED_CLASS!>actual typealias Bar3 = JavaBar<!>
+actual class <!NO_ACTUAL_CLASS_MEMBER_FOR_EXPECTED_CLASS!>Bar1<!>(val s: String)
+actual class <!NO_ACTUAL_CLASS_MEMBER_FOR_EXPECTED_CLASS!>Bar2<!>(val p: String = "value", i: Int)
+actual typealias <!NO_ACTUAL_CLASS_MEMBER_FOR_EXPECTED_CLASS!>Bar3<!> = JavaBar
 actual class Bar4(val s: String) {
     constructor() : this("")
 }
diff --git a/compiler/testData/diagnostics/tests/multiplatform/headerClass/expectDeclarationWithWeakIncompatibilities.fir.kt b/compiler/testData/diagnostics/tests/multiplatform/headerClass/expectDeclarationWithWeakIncompatibilities.fir.kt
index 04562c0e29e..e7ea59d4d0c 100644
--- a/compiler/testData/diagnostics/tests/multiplatform/headerClass/expectDeclarationWithWeakIncompatibilities.fir.kt
+++ b/compiler/testData/diagnostics/tests/multiplatform/headerClass/expectDeclarationWithWeakIncompatibilities.fir.kt
@@ -23,6 +23,6 @@ interface Foo1
 
 fun foo2(): Int = 0
 
-<!ACTUAL_WITHOUT_EXPECT, REDECLARATION!>actual class Foo3<!>
+<!ACTUAL_WITHOUT_EXPECT!>actual class <!PACKAGE_OR_CLASSIFIER_REDECLARATION!>Foo3<!><!>
 
-<!REDECLARATION!>class Foo3<!>
+class <!PACKAGE_OR_CLASSIFIER_REDECLARATION!>Foo3<!>
diff --git a/compiler/testData/diagnostics/tests/multiplatform/headerClass/nestedClassesWithErrors.fir.kt b/compiler/testData/diagnostics/tests/multiplatform/headerClass/nestedClassesWithErrors.fir.kt
index 5431aebb3bf..094c389f403 100644
--- a/compiler/testData/diagnostics/tests/multiplatform/headerClass/nestedClassesWithErrors.fir.kt
+++ b/compiler/testData/diagnostics/tests/multiplatform/headerClass/nestedClassesWithErrors.fir.kt
@@ -39,7 +39,7 @@ actual class C {
     actual inner class I
 }
 
-<!NO_ACTUAL_CLASS_MEMBER_FOR_EXPECTED_CLASS!>actual class D<!>
+actual class <!NO_ACTUAL_CLASS_MEMBER_FOR_EXPECTED_CLASS!>D<!>
 
 actual class E {
     class N
diff --git a/compiler/testData/diagnostics/tests/multiplatform/implDynamic.fir.kt b/compiler/testData/diagnostics/tests/multiplatform/implDynamic.fir.kt
index 799d38c08d1..ab745196cff 100644
--- a/compiler/testData/diagnostics/tests/multiplatform/implDynamic.fir.kt
+++ b/compiler/testData/diagnostics/tests/multiplatform/implDynamic.fir.kt
@@ -18,7 +18,7 @@ expect class Foo {
 
 // TODO: do not suppress UNSUPPORTED once JS files in multi-platform tests are analyzed with JS analyzer facade
 
-<!NO_ACTUAL_CLASS_MEMBER_FOR_EXPECTED_CLASS!>actual class Foo {
+actual class <!NO_ACTUAL_CLASS_MEMBER_FOR_EXPECTED_CLASS!>Foo<!> {
     <!ACTUAL_WITHOUT_EXPECT!>actual constructor(p: dynamic) {}<!>
 
     <!ACTUAL_WITHOUT_EXPECT!>actual fun f1(s: dynamic): dynamic = null!!<!>
@@ -26,4 +26,4 @@ expect class Foo {
     <!ACTUAL_WITHOUT_EXPECT!>actual fun f2(s: dynamic): MutableMap<Boolean?, Foo> = null!!<!>
 
     <!ACTUAL_WITHOUT_EXPECT!>actual fun <T : Set<Number>> f3(t: T): dynamic = null!!<!>
-}<!>
+}
diff --git a/compiler/testData/diagnostics/tests/multiplatform/inlineClasses/expectActualInlineClass.fir.kt b/compiler/testData/diagnostics/tests/multiplatform/inlineClasses/expectActualInlineClass.fir.kt
index ed45beb8df1..dfb2e466e3e 100644
--- a/compiler/testData/diagnostics/tests/multiplatform/inlineClasses/expectActualInlineClass.fir.kt
+++ b/compiler/testData/diagnostics/tests/multiplatform/inlineClasses/expectActualInlineClass.fir.kt
@@ -20,7 +20,7 @@ expect inline class NonInlineActual(val x: Int)
 actual inline class Foo1(val x: Int) {
     actual fun bar(): String = "Hello"
 }
-<!NO_ACTUAL_CLASS_MEMBER_FOR_EXPECTED_CLASS!>actual inline class Foo2(val x: String)<!>
+actual inline class <!NO_ACTUAL_CLASS_MEMBER_FOR_EXPECTED_CLASS!>Foo2<!>(val x: String)
 actual <!ABSENCE_OF_PRIMARY_CONSTRUCTOR_FOR_INLINE_CLASS!>inline<!> class Foo3
 
 <!ACTUAL_WITHOUT_EXPECT!>actual inline class NonInlineExpect(val x: Int)<!>
diff --git a/compiler/testData/diagnostics/tests/overload/ConflictingOverloadsIdenticalValsInClass.fir.kt b/compiler/testData/diagnostics/tests/overload/ConflictingOverloadsIdenticalValsInClass.fir.kt
deleted file mode 100644
index 2ca7e2c8faf..00000000000
--- a/compiler/testData/diagnostics/tests/overload/ConflictingOverloadsIdenticalValsInClass.fir.kt
+++ /dev/null
@@ -1,4 +0,0 @@
-class Aaa() {
-    <!REDECLARATION!>val a = 1<!>
-    <!REDECLARATION!>val a = 1<!>
-}
\ No newline at end of file
diff --git a/compiler/testData/diagnostics/tests/overload/ConflictingOverloadsIdenticalValsInClass.kt b/compiler/testData/diagnostics/tests/overload/ConflictingOverloadsIdenticalValsInClass.kt
index 1aec18caa64..ab03558dd98 100644
--- a/compiler/testData/diagnostics/tests/overload/ConflictingOverloadsIdenticalValsInClass.kt
+++ b/compiler/testData/diagnostics/tests/overload/ConflictingOverloadsIdenticalValsInClass.kt
@@ -1,3 +1,4 @@
+// FIR_IDENTICAL
 class Aaa() {
     val <!REDECLARATION!>a<!> = 1
     val <!REDECLARATION!>a<!> = 1
diff --git a/compiler/testData/diagnostics/tests/overload/ConflictingOverloadsValsDifferentTypeInClass.fir.kt b/compiler/testData/diagnostics/tests/overload/ConflictingOverloadsValsDifferentTypeInClass.fir.kt
deleted file mode 100644
index 876bcfe753b..00000000000
--- a/compiler/testData/diagnostics/tests/overload/ConflictingOverloadsValsDifferentTypeInClass.fir.kt
+++ /dev/null
@@ -1,4 +0,0 @@
-class Aaa() {
-    <!REDECLARATION!>val a = 1<!>
-    <!REDECLARATION!>val a = ""<!>
-}
\ No newline at end of file
diff --git a/compiler/testData/diagnostics/tests/overload/ConflictingOverloadsValsDifferentTypeInClass.kt b/compiler/testData/diagnostics/tests/overload/ConflictingOverloadsValsDifferentTypeInClass.kt
index 44872ce40b8..6aa020e8e3f 100644
--- a/compiler/testData/diagnostics/tests/overload/ConflictingOverloadsValsDifferentTypeInClass.kt
+++ b/compiler/testData/diagnostics/tests/overload/ConflictingOverloadsValsDifferentTypeInClass.kt
@@ -1,3 +1,4 @@
+// FIR_IDENTICAL
 class Aaa() {
     val <!REDECLARATION!>a<!> = 1
     val <!REDECLARATION!>a<!> = ""
diff --git a/compiler/testData/diagnostics/tests/redeclarations/ClassRedeclarationInDifferentFiles.fir.kt b/compiler/testData/diagnostics/tests/redeclarations/ClassRedeclarationInDifferentFiles.fir.kt
deleted file mode 100644
index bd4419cd9f3..00000000000
--- a/compiler/testData/diagnostics/tests/redeclarations/ClassRedeclarationInDifferentFiles.fir.kt
+++ /dev/null
@@ -1,12 +0,0 @@
-// FIR_IDE_IGNORE
-// FILE: f1.kt
-package test
-
-<!REDECLARATION!>class A<!>
-class F1
-
-// FILE: f2.kt
-package test
-
-<!REDECLARATION!>class A<!>
-class F2
\ No newline at end of file
diff --git a/compiler/testData/diagnostics/tests/redeclarations/ClassRedeclarationInDifferentFiles.kt b/compiler/testData/diagnostics/tests/redeclarations/ClassRedeclarationInDifferentFiles.kt
index b374beefba0..bc4c9bd9d9b 100644
--- a/compiler/testData/diagnostics/tests/redeclarations/ClassRedeclarationInDifferentFiles.kt
+++ b/compiler/testData/diagnostics/tests/redeclarations/ClassRedeclarationInDifferentFiles.kt
@@ -1,3 +1,4 @@
+// FIR_IDENTICAL
 // FIR_IDE_IGNORE
 // FILE: f1.kt
 package test
diff --git a/compiler/testData/diagnostics/tests/redeclarations/ConflictingExtensionProperties.fir.kt b/compiler/testData/diagnostics/tests/redeclarations/ConflictingExtensionProperties.fir.kt
deleted file mode 100644
index 0641d9932d6..00000000000
--- a/compiler/testData/diagnostics/tests/redeclarations/ConflictingExtensionProperties.fir.kt
+++ /dev/null
@@ -1,4 +0,0 @@
-package foo
-
-<!REDECLARATION!>val Int.foo: Int get() = 2<!>
-<!REDECLARATION!>val Int.foo: Int get() = 3<!>
diff --git a/compiler/testData/diagnostics/tests/redeclarations/ConflictingExtensionProperties.kt b/compiler/testData/diagnostics/tests/redeclarations/ConflictingExtensionProperties.kt
index 6e3a6e2b70e..f5aa901b29b 100644
--- a/compiler/testData/diagnostics/tests/redeclarations/ConflictingExtensionProperties.kt
+++ b/compiler/testData/diagnostics/tests/redeclarations/ConflictingExtensionProperties.kt
@@ -1,3 +1,4 @@
+// FIR_IDENTICAL
 package foo
 
 val Int.<!REDECLARATION!>foo<!>: Int get() = 2
diff --git a/compiler/testData/diagnostics/tests/redeclarations/PropertyAndInnerClass.fir.kt b/compiler/testData/diagnostics/tests/redeclarations/PropertyAndInnerClass.fir.kt
deleted file mode 100644
index 2e7f81b2f2c..00000000000
--- a/compiler/testData/diagnostics/tests/redeclarations/PropertyAndInnerClass.fir.kt
+++ /dev/null
@@ -1,13 +0,0 @@
-public class A() {
-    <!REDECLARATION!>public val FOO: String = "test"<!>
-
-    <!REDECLARATION!>public class FOO() { }<!>
-}
-
-public class B() {
-   companion object {
-      <!REDECLARATION!>public val FOO: String = "test"<!>
-      
-      <!REDECLARATION!>public class FOO() { }<!>
-   }
-}
diff --git a/compiler/testData/diagnostics/tests/redeclarations/PropertyAndInnerClass.kt b/compiler/testData/diagnostics/tests/redeclarations/PropertyAndInnerClass.kt
index e12816b85f7..2fecea991db 100644
--- a/compiler/testData/diagnostics/tests/redeclarations/PropertyAndInnerClass.kt
+++ b/compiler/testData/diagnostics/tests/redeclarations/PropertyAndInnerClass.kt
@@ -1,3 +1,4 @@
+// FIR_IDENTICAL
 public class A() {
     public val <!REDECLARATION!>FOO<!>: String = "test"
 
diff --git a/compiler/testData/diagnostics/tests/redeclarations/RedeclarationInDefaultObject.fir.kt b/compiler/testData/diagnostics/tests/redeclarations/RedeclarationInDefaultObject.fir.kt
deleted file mode 100644
index fafb3741ebb..00000000000
--- a/compiler/testData/diagnostics/tests/redeclarations/RedeclarationInDefaultObject.fir.kt
+++ /dev/null
@@ -1,6 +0,0 @@
-class A {
-    companion object B {
-        <!REDECLARATION!>class G<!>
-        <!REDECLARATION!>val G = 1<!>
-    }
-}
\ No newline at end of file
diff --git a/compiler/testData/diagnostics/tests/redeclarations/RedeclarationInDefaultObject.kt b/compiler/testData/diagnostics/tests/redeclarations/RedeclarationInDefaultObject.kt
index 856d17914a8..d3720d45bdc 100644
--- a/compiler/testData/diagnostics/tests/redeclarations/RedeclarationInDefaultObject.kt
+++ b/compiler/testData/diagnostics/tests/redeclarations/RedeclarationInDefaultObject.kt
@@ -1,3 +1,4 @@
+// FIR_IDENTICAL
 class A {
     companion object B {
         class <!REDECLARATION!>G<!>
diff --git a/compiler/testData/diagnostics/tests/redeclarations/RedeclarationInMultiFile.fir.kt b/compiler/testData/diagnostics/tests/redeclarations/RedeclarationInMultiFile.fir.kt
deleted file mode 100644
index 676291d6c5d..00000000000
--- a/compiler/testData/diagnostics/tests/redeclarations/RedeclarationInMultiFile.fir.kt
+++ /dev/null
@@ -1,9 +0,0 @@
-// FILE: a.kt
-<!REDECLARATION!>val a : Int = 1<!>
-<!CONFLICTING_OVERLOADS!>fun f()<!> {
-}
-
-// FILE: b.kt
-<!REDECLARATION!>val a : Int = 1<!>
-<!CONFLICTING_OVERLOADS!>fun f()<!> {
-}
diff --git a/compiler/testData/diagnostics/tests/redeclarations/RedeclarationInMultiFile.kt b/compiler/testData/diagnostics/tests/redeclarations/RedeclarationInMultiFile.kt
index fafba886a28..e76c61628bd 100644
--- a/compiler/testData/diagnostics/tests/redeclarations/RedeclarationInMultiFile.kt
+++ b/compiler/testData/diagnostics/tests/redeclarations/RedeclarationInMultiFile.kt
@@ -1,3 +1,4 @@
+// FIR_IDENTICAL
 // FILE: a.kt
 val <!REDECLARATION!>a<!> : Int = 1
 <!CONFLICTING_OVERLOADS!>fun f()<!> {
diff --git a/compiler/testData/diagnostics/tests/redeclarations/Redeclarations.fir.kt b/compiler/testData/diagnostics/tests/redeclarations/Redeclarations.fir.kt
index c4def7ab452..c27ff56d29f 100644
--- a/compiler/testData/diagnostics/tests/redeclarations/Redeclarations.fir.kt
+++ b/compiler/testData/diagnostics/tests/redeclarations/Redeclarations.fir.kt
@@ -1,14 +1,14 @@
 // FILE: a.kt
 package redeclarations
-  <!REDECLARATION!>object A<!> {
+  object <!PACKAGE_OR_CLASSIFIER_REDECLARATION!>A<!> {
     val x : Int = 0
 
     val A = 1
   }
 
-  <!REDECLARATION!>class A {}<!>
+  class <!PACKAGE_OR_CLASSIFIER_REDECLARATION!>A<!> {}
 
-  <!REDECLARATION!>val A = 1<!>
+  val <!REDECLARATION!>A<!> = 1
 
 // FILE: b.kt
   package redeclarations.A
diff --git a/compiler/testData/diagnostics/tests/redeclarations/RedeclarationsInObjects.fir.kt b/compiler/testData/diagnostics/tests/redeclarations/RedeclarationsInObjects.fir.kt
deleted file mode 100644
index dd67dab11f3..00000000000
--- a/compiler/testData/diagnostics/tests/redeclarations/RedeclarationsInObjects.fir.kt
+++ /dev/null
@@ -1,9 +0,0 @@
-// !DIAGNOSTICS: -DUPLICATE_CLASS_NAMES
-// KT-3525
-object B {
-    <!REDECLARATION!>class C<!>
-    <!REDECLARATION!>class C<!>
-
-    <!REDECLARATION!>val a : Int = 1<!>
-    <!REDECLARATION!>val a : Int = 1<!>
-}
\ No newline at end of file
diff --git a/compiler/testData/diagnostics/tests/redeclarations/RedeclarationsInObjects.kt b/compiler/testData/diagnostics/tests/redeclarations/RedeclarationsInObjects.kt
index 7469947ed69..94e0f99846d 100644
--- a/compiler/testData/diagnostics/tests/redeclarations/RedeclarationsInObjects.kt
+++ b/compiler/testData/diagnostics/tests/redeclarations/RedeclarationsInObjects.kt
@@ -1,3 +1,4 @@
+// FIR_IDENTICAL
 // !DIAGNOSTICS: -DUPLICATE_CLASS_NAMES
 // KT-3525
 object B {
diff --git a/compiler/testData/diagnostics/tests/redeclarations/RedeclaringPrivateToFile.fir.kt b/compiler/testData/diagnostics/tests/redeclarations/RedeclaringPrivateToFile.fir.kt
index 938236dd0c0..08b2df68909 100644
--- a/compiler/testData/diagnostics/tests/redeclarations/RedeclaringPrivateToFile.fir.kt
+++ b/compiler/testData/diagnostics/tests/redeclarations/RedeclaringPrivateToFile.fir.kt
@@ -8,7 +8,7 @@ private fun validFun() {}
 private val validVal = 1
 
 <!CONFLICTING_OVERLOADS!>private fun invalidFun0()<!> {}
-<!REDECLARATION!>private val invalidProp0 = 1<!>
+private val <!REDECLARATION!>invalidProp0<!> = 1
 
 // NB invalidFun0 and invalidProp0 are conflicting overloads, since the following is an ambiguity:
 fun useInvalidFun0() = invalidFun0()
@@ -36,7 +36,7 @@ private val validVal = 1
 
 <!CONFLICTING_OVERLOADS!>private fun invalidFun0()<!> {}
 
-<!REDECLARATION!>private val invalidProp0 = 1<!>
+private val <!REDECLARATION!>invalidProp0<!> = 1
 
 <!CONFLICTING_OVERLOADS!>internal fun invalidFun3()<!> {}
 <!CONFLICTING_OVERLOADS!>internal fun invalidFun4()<!> {}
diff --git a/compiler/testData/diagnostics/tests/redeclarations/TopLevelPropertyVsClassifier.fir.kt b/compiler/testData/diagnostics/tests/redeclarations/TopLevelPropertyVsClassifier.fir.kt
index 35619073911..364c7d0402b 100644
--- a/compiler/testData/diagnostics/tests/redeclarations/TopLevelPropertyVsClassifier.fir.kt
+++ b/compiler/testData/diagnostics/tests/redeclarations/TopLevelPropertyVsClassifier.fir.kt
@@ -1,13 +1,13 @@
-<!REDECLARATION!>val Test1 = null<!>
-<!REDECLARATION!>class Test1<!>
+val <!REDECLARATION!>Test1<!> = null
+class <!REDECLARATION!>Test1<!>
 
-<!REDECLARATION!>val Test2 = null<!>
-<!REDECLARATION!>interface Test2<!>
+val <!REDECLARATION!>Test2<!> = null
+interface <!REDECLARATION!>Test2<!>
 
-<!REDECLARATION!>val Test3 = null<!>
-<!REDECLARATION!>object Test3<!>
+val <!REDECLARATION!>Test3<!> = null
+object <!REDECLARATION!>Test3<!>
 
-<!REDECLARATION!>val Test4 = null<!>
-<!REDECLARATION!>class Test4<!>
-<!REDECLARATION!>interface Test4<!>
-<!REDECLARATION!>object Test4<!>
\ No newline at end of file
+val <!REDECLARATION!>Test4<!> = null
+class <!PACKAGE_OR_CLASSIFIER_REDECLARATION!>Test4<!>
+interface <!PACKAGE_OR_CLASSIFIER_REDECLARATION!>Test4<!>
+object <!PACKAGE_OR_CLASSIFIER_REDECLARATION!>Test4<!>
\ No newline at end of file
diff --git a/compiler/testData/diagnostics/tests/redeclarations/TypeAliasVsClass.fir.kt b/compiler/testData/diagnostics/tests/redeclarations/TypeAliasVsClass.fir.kt
deleted file mode 100644
index 3f2237e17a2..00000000000
--- a/compiler/testData/diagnostics/tests/redeclarations/TypeAliasVsClass.fir.kt
+++ /dev/null
@@ -1,18 +0,0 @@
-// !DIAGNOSTICS: -UNUSED_VARIABLE -UNUSED_PARAMETER -TOPLEVEL_TYPEALIASES_ONLY
-// FILE: file1.kt
-<!REDECLARATION!>class SomeClass<!>
-
-<!REDECLARATION!>typealias SomeClass = Any<!>
-<!REDECLARATION!>typealias SomeClass = Any<!>
-<!REDECLARATION!>typealias SomeClass = Any<!>
-
-class Outer {
-    <!REDECLARATION!>class Nested<!>
-
-    <!REDECLARATION!>typealias Nested = Any<!>
-    <!REDECLARATION!>typealias Nested = Any<!>
-    <!REDECLARATION!>typealias Nested = Any<!>
-}
-
-// FILE: file2.kt
-<!REDECLARATION!>typealias SomeClass = Any<!>
diff --git a/compiler/testData/diagnostics/tests/redeclarations/TypeAliasVsClass.kt b/compiler/testData/diagnostics/tests/redeclarations/TypeAliasVsClass.kt
index 09cab9f306e..c62bb7c6264 100644
--- a/compiler/testData/diagnostics/tests/redeclarations/TypeAliasVsClass.kt
+++ b/compiler/testData/diagnostics/tests/redeclarations/TypeAliasVsClass.kt
@@ -1,3 +1,4 @@
+// FIR_IDENTICAL
 // !DIAGNOSTICS: -UNUSED_VARIABLE -UNUSED_PARAMETER -TOPLEVEL_TYPEALIASES_ONLY
 // FILE: file1.kt
 class <!PACKAGE_OR_CLASSIFIER_REDECLARATION!>SomeClass<!>
diff --git a/compiler/testData/diagnostics/tests/redeclarations/TypeAliasVsProperty.fir.kt b/compiler/testData/diagnostics/tests/redeclarations/TypeAliasVsProperty.fir.kt
index 0f13bcbbeca..20f9a58ebce 100644
--- a/compiler/testData/diagnostics/tests/redeclarations/TypeAliasVsProperty.fir.kt
+++ b/compiler/testData/diagnostics/tests/redeclarations/TypeAliasVsProperty.fir.kt
@@ -1,13 +1,13 @@
 // !DIAGNOSTICS: -UNUSED_VARIABLE -UNUSED_PARAMETER -TOPLEVEL_TYPEALIASES_ONLY
 // FILE: file1.kt
-<!REDECLARATION!>typealias Test = String<!>
+typealias <!REDECLARATION!>Test<!> = String
 
-<!REDECLARATION!>val Test = 42<!>
+val <!REDECLARATION!>Test<!> = 42
 
 class Outer {
-    <!REDECLARATION!>typealias Test = String<!>
+    typealias <!REDECLARATION!>Test<!> = String
 
-    <!REDECLARATION!>val Test = 42<!>
+    val <!REDECLARATION!>Test<!> = 42
 }
 
 typealias Test2 = String
diff --git a/compiler/testData/diagnostics/tests/redeclarations/kt2438.fir.kt b/compiler/testData/diagnostics/tests/redeclarations/kt2438.fir.kt
deleted file mode 100644
index b580e859b03..00000000000
--- a/compiler/testData/diagnostics/tests/redeclarations/kt2438.fir.kt
+++ /dev/null
@@ -1,22 +0,0 @@
-// !DIAGNOSTICS: -DUPLICATE_CLASS_NAMES
-//KT-2438 Prohibit inner classes with the same name
-
-package kt2438
-
-class B {
-    <!REDECLARATION!>class C<!>
-    <!REDECLARATION!>class C<!>
-}
-
-
-
-class A {
-    <!REDECLARATION!>class B<!>
-    
-    companion object {
-        <!REDECLARATION!>class B<!>
-        <!REDECLARATION!>class B<!>
-    }
-    
-    <!REDECLARATION!>class B<!>
-}
diff --git a/compiler/testData/diagnostics/tests/redeclarations/kt2438.kt b/compiler/testData/diagnostics/tests/redeclarations/kt2438.kt
index efb790f6394..2952251a5fe 100644
--- a/compiler/testData/diagnostics/tests/redeclarations/kt2438.kt
+++ b/compiler/testData/diagnostics/tests/redeclarations/kt2438.kt
@@ -1,3 +1,4 @@
+// FIR_IDENTICAL
 // !DIAGNOSTICS: -DUPLICATE_CLASS_NAMES
 //KT-2438 Prohibit inner classes with the same name
 
diff --git a/compiler/testData/diagnostics/tests/redeclarations/kt470.fir.kt b/compiler/testData/diagnostics/tests/redeclarations/kt470.fir.kt
deleted file mode 100644
index b8732450a9e..00000000000
--- a/compiler/testData/diagnostics/tests/redeclarations/kt470.fir.kt
+++ /dev/null
@@ -1,37 +0,0 @@
-<!REDECLARATION!>val a : Int = 1<!>
-<!REDECLARATION!>val a : Int = 1<!>
-<!REDECLARATION!>val a : Int = 1<!>
-
-<!REDECLARATION!>val b : Int = 1<!>
-<!REDECLARATION!>val b : Int = 1<!>
-<!REDECLARATION!>val b : Int = 1<!>
-<!REDECLARATION!>val b : Int = 1<!>
-
-<!CONFLICTING_OVERLOADS!>fun foo()<!> {} // and here too
-<!CONFLICTING_OVERLOADS!>fun foo()<!> {} // and here
-<!CONFLICTING_OVERLOADS!>fun foo()<!> {} // and here
-<!CONFLICTING_OVERLOADS!>fun foo()<!> {} // and here
-
-<!CONFLICTING_OVERLOADS!>fun bar()<!> {} // and here
-<!CONFLICTING_OVERLOADS!>fun bar()<!> {} // and here
-<!CONFLICTING_OVERLOADS!>fun bar()<!> {} // and here
-
-class A {
-    <!REDECLARATION!>val a : Int = 1<!>
-    <!REDECLARATION!>val a : Int = 1<!>
-    <!REDECLARATION!>val a : Int = 1<!>
-
-    <!REDECLARATION!>val b : Int = 1<!>
-    <!REDECLARATION!>val b : Int = 1<!>
-    <!REDECLARATION!>val b : Int = 1<!>
-    <!REDECLARATION!>val b : Int = 1<!>
-
-    <!CONFLICTING_OVERLOADS!>fun foo()<!> {} // and here too
-    <!CONFLICTING_OVERLOADS!>fun foo()<!> {} // and here
-    <!CONFLICTING_OVERLOADS!>fun foo()<!> {} // and here
-    <!CONFLICTING_OVERLOADS!>fun foo()<!> {} // and here
-
-    <!CONFLICTING_OVERLOADS!>fun bar()<!> {} // and here
-    <!CONFLICTING_OVERLOADS!>fun bar()<!> {} // and here
-    <!CONFLICTING_OVERLOADS!>fun bar()<!> {} // and here
-}
diff --git a/compiler/testData/diagnostics/tests/redeclarations/kt470.kt b/compiler/testData/diagnostics/tests/redeclarations/kt470.kt
index f8c5fff6abe..de123fb873f 100644
--- a/compiler/testData/diagnostics/tests/redeclarations/kt470.kt
+++ b/compiler/testData/diagnostics/tests/redeclarations/kt470.kt
@@ -1,3 +1,4 @@
+// FIR_IDENTICAL
 val <!REDECLARATION!>a<!> : Int = 1
 val <!REDECLARATION!>a<!> : Int = 1
 val <!REDECLARATION!>a<!> : Int = 1
diff --git a/compiler/testData/diagnostics/tests/regressions/Jet11.fir.kt b/compiler/testData/diagnostics/tests/regressions/Jet11.fir.kt
deleted file mode 100644
index 5f95d00270d..00000000000
--- a/compiler/testData/diagnostics/tests/regressions/Jet11.fir.kt
+++ /dev/null
@@ -1,4 +0,0 @@
-// JET-11 Redeclaration & Forward reference for classes cause an exception
-<!REDECLARATION!>open class NoC<!>
-class NoC1 : NoC()
-<!REDECLARATION!>open class NoC<!>
diff --git a/compiler/testData/diagnostics/tests/regressions/Jet11.kt b/compiler/testData/diagnostics/tests/regressions/Jet11.kt
index fa244c155c8..bcecdb49690 100644
--- a/compiler/testData/diagnostics/tests/regressions/Jet11.kt
+++ b/compiler/testData/diagnostics/tests/regressions/Jet11.kt
@@ -1,3 +1,4 @@
+// FIR_IDENTICAL
 // JET-11 Redeclaration & Forward reference for classes cause an exception
 open class <!PACKAGE_OR_CLASSIFIER_REDECLARATION!>NoC<!>
 class NoC1 : NoC()
diff --git a/compiler/testData/diagnostics/tests/secondaryConstructors/redeclarationsOfConstructorsIgnored.fir.kt b/compiler/testData/diagnostics/tests/secondaryConstructors/redeclarationsOfConstructorsIgnored.fir.kt
deleted file mode 100644
index 6df18e93ac3..00000000000
--- a/compiler/testData/diagnostics/tests/secondaryConstructors/redeclarationsOfConstructorsIgnored.fir.kt
+++ /dev/null
@@ -1,11 +0,0 @@
-<!REDECLARATION!>class A<!>
-<!REDECLARATION!>class A {
-    constructor()
-}<!>
-
-class B
-class Outer {
-    class B {
-        constructor()
-    }
-}
diff --git a/compiler/testData/diagnostics/tests/secondaryConstructors/redeclarationsOfConstructorsIgnored.kt b/compiler/testData/diagnostics/tests/secondaryConstructors/redeclarationsOfConstructorsIgnored.kt
index 8391b02d6e3..7bf761fedb2 100644
--- a/compiler/testData/diagnostics/tests/secondaryConstructors/redeclarationsOfConstructorsIgnored.kt
+++ b/compiler/testData/diagnostics/tests/secondaryConstructors/redeclarationsOfConstructorsIgnored.kt
@@ -1,3 +1,4 @@
+// FIR_IDENTICAL
 class <!PACKAGE_OR_CLASSIFIER_REDECLARATION!>A<!>
 class <!PACKAGE_OR_CLASSIFIER_REDECLARATION!>A<!> {
     constructor()
diff --git a/compiler/testData/diagnostics/tests/typealias/privateInFile.fir.kt b/compiler/testData/diagnostics/tests/typealias/privateInFile.fir.kt
index b4a94971e0f..333368c030a 100644
--- a/compiler/testData/diagnostics/tests/typealias/privateInFile.fir.kt
+++ b/compiler/testData/diagnostics/tests/typealias/privateInFile.fir.kt
@@ -19,5 +19,5 @@ private val test1co: C.Companion = <!INITIALIZER_TYPE_MISMATCH, NO_COMPANION_OBJ
 private val test2: TA = <!INITIALIZER_TYPE_MISMATCH!>TA(<!NO_VALUE_FOR_PARAMETER!>)<!><!>
 private val test2co = TA
 
-<!REDECLARATION!>private class C<!>
-<!REDECLARATION!>private typealias TA = Int<!>
+private class <!PACKAGE_OR_CLASSIFIER_REDECLARATION!>C<!>
+private typealias <!PACKAGE_OR_CLASSIFIER_REDECLARATION!>TA<!> = Int
diff --git a/compiler/tests-spec/testData/diagnostics/linked/declarations/classifier-declaration/class-declaration/abstract-classes/p-2/neg/1.4.fir.kt b/compiler/tests-spec/testData/diagnostics/linked/declarations/classifier-declaration/class-declaration/abstract-classes/p-2/neg/1.4.fir.kt
index 1a0e11e0205..335f474483d 100644
--- a/compiler/tests-spec/testData/diagnostics/linked/declarations/classifier-declaration/class-declaration/abstract-classes/p-2/neg/1.4.fir.kt
+++ b/compiler/tests-spec/testData/diagnostics/linked/declarations/classifier-declaration/class-declaration/abstract-classes/p-2/neg/1.4.fir.kt
@@ -54,9 +54,9 @@ class Case2() {
 * TESTCASE NUMBER: 3
 * NOTE: check abstract member cannot be accessed directly
 */
-class Case3(<!REDECLARATION!>override val boo: String<!>) : BaseCase3() {
+class Case3(override val <!REDECLARATION!>boo<!>: String) : BaseCase3() {
     override val zoo: String = super.<!ABSTRACT_SUPER_CALL!>foo<!>()
-    <!REDECLARATION!>override val boo: String = super.<!ABSTRACT_SUPER_CALL!>boo<!><!>
+    override val <!REDECLARATION!>boo<!>: String = super.<!ABSTRACT_SUPER_CALL!>boo<!>
     override val value: String = super.<!ABSTRACT_SUPER_CALL!>zoo<!>
     val hoo: String = super.<!ABSTRACT_SUPER_CALL!>zoo<!>
 
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 3425811e6c4..f4d214b854d 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
@@ -1929,6 +1929,15 @@ internal val KT_DIAGNOSTIC_CONVERTER = KtDiagnosticConverterBuilder.buildConvert
             token,
         )
     }
+    add(FirErrors.PACKAGE_OR_CLASSIFIER_REDECLARATION) { firDiagnostic ->
+        PackageOrClassifierRedeclarationImpl(
+            firDiagnostic.a.map { firBasedSymbol ->
+                firSymbolBuilder.buildSymbol(firBasedSymbol.fir)
+            },
+            firDiagnostic as FirPsiDiagnostic,
+            token,
+        )
+    }
     add(FirErrors.METHOD_OF_ANY_IMPLEMENTED_IN_INTERFACE) { firDiagnostic ->
         MethodOfAnyImplementedInInterfaceImpl(
             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 23079e14913..681f861b8e0 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
@@ -1369,11 +1369,16 @@ sealed class KtFirDiagnostic<PSI : PsiElement> : KtDiagnosticWithPsi<PSI> {
         abstract val conflictingOverloads: List<KtSymbol>
     }
 
-    abstract class Redeclaration : KtFirDiagnostic<PsiElement>() {
+    abstract class Redeclaration : KtFirDiagnostic<KtNamedDeclaration>() {
         override val diagnosticClass get() = Redeclaration::class
         abstract val conflictingDeclarations: List<KtSymbol>
     }
 
+    abstract class PackageOrClassifierRedeclaration : KtFirDiagnostic<KtNamedDeclaration>() {
+        override val diagnosticClass get() = PackageOrClassifierRedeclaration::class
+        abstract val conflictingDeclarations: List<KtSymbol>
+    }
+
     abstract class MethodOfAnyImplementedInInterface : KtFirDiagnostic<PsiElement>() {
         override val diagnosticClass get() = MethodOfAnyImplementedInInterface::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 a21849eb1a7..d83652959da 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
@@ -2187,7 +2187,15 @@ internal class RedeclarationImpl(
     override val conflictingDeclarations: List<KtSymbol>,
     firDiagnostic: FirPsiDiagnostic,
     override val token: ValidityToken,
-) : KtFirDiagnostic.Redeclaration(), KtAbstractFirDiagnostic<PsiElement> {
+) : KtFirDiagnostic.Redeclaration(), KtAbstractFirDiagnostic<KtNamedDeclaration> {
+    override val firDiagnostic: FirPsiDiagnostic by weakRef(firDiagnostic)
+}
+
+internal class PackageOrClassifierRedeclarationImpl(
+    override val conflictingDeclarations: List<KtSymbol>,
+    firDiagnostic: FirPsiDiagnostic,
+    override val token: ValidityToken,
+) : KtFirDiagnostic.PackageOrClassifierRedeclaration(), KtAbstractFirDiagnostic<KtNamedDeclaration> {
     override val firDiagnostic: FirPsiDiagnostic by weakRef(firDiagnostic)
 }