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 058470f0584..444740ffba4 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
@@ -140,6 +140,16 @@ object DIAGNOSTICS_LIST : DiagnosticList("FirErrors") {
             parameter<ConeKotlinType>("type")
         }
         val PROJECTION_IN_IMMEDIATE_ARGUMENT_TO_SUPERTYPE by error<KtModifierListOwner>(PositioningStrategy.VARIANCE_MODIFIER)
+        val INCONSISTENT_TYPE_PARAMETER_VALUES by error<KtClass>(PositioningStrategy.SUPERTYPES_LIST) {
+            parameter<FirTypeParameterSymbol>("typeParameter")
+            parameter<FirRegularClassSymbol>("type")
+            parameter<Collection<ConeKotlinType>>("bounds")
+        }
+        val INCONSISTENT_TYPE_PARAMETER_BOUNDS by error<PsiElement> {
+            parameter<FirTypeParameterSymbol>("typeParameter")
+            parameter<FirRegularClassSymbol>("type")
+            parameter<Collection<ConeKotlinType>>("bounds")
+        }
     }
 
     val CONSTRUCTOR_PROBLEMS by object : DiagnosticGroup("Constructor problems") {
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 f41dc5d0149..86b1996e475 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
@@ -146,6 +146,8 @@ object FirErrors {
     val CYCLIC_INHERITANCE_HIERARCHY by error0<PsiElement>()
     val EXPANDED_TYPE_CANNOT_BE_INHERITED by error1<KtTypeReference, ConeKotlinType>()
     val PROJECTION_IN_IMMEDIATE_ARGUMENT_TO_SUPERTYPE by error0<KtModifierListOwner>(SourceElementPositioningStrategies.VARIANCE_MODIFIER)
+    val INCONSISTENT_TYPE_PARAMETER_VALUES by error3<KtClass, FirTypeParameterSymbol, FirRegularClassSymbol, Collection<ConeKotlinType>>(SourceElementPositioningStrategies.SUPERTYPES_LIST)
+    val INCONSISTENT_TYPE_PARAMETER_BOUNDS by error3<PsiElement, FirTypeParameterSymbol, FirRegularClassSymbol, Collection<ConeKotlinType>>()
 
     // Constructor problems
     val CONSTRUCTOR_IN_OBJECT by error0<KtDeclaration>(SourceElementPositioningStrategies.DECLARATION_SIGNATURE)
diff --git a/compiler/fir/checkers/src/org/jetbrains/kotlin/fir/analysis/checkers/FirInconsistentTypeParameterHelpers.kt b/compiler/fir/checkers/src/org/jetbrains/kotlin/fir/analysis/checkers/FirInconsistentTypeParameterHelpers.kt
new file mode 100644
index 00000000000..1f21e7f2fb0
--- /dev/null
+++ b/compiler/fir/checkers/src/org/jetbrains/kotlin/fir/analysis/checkers/FirInconsistentTypeParameterHelpers.kt
@@ -0,0 +1,118 @@
+/*
+ * Copyright 2010-2021 JetBrains s.r.o. and Kotlin Programming Language contributors.
+ * Use of this source code is governed by the Apache 2.0 license that can be found in the license/LICENSE.txt file.
+ */
+
+package org.jetbrains.kotlin.fir.analysis.checkers
+
+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.reportOn
+import org.jetbrains.kotlin.fir.analysis.diagnostics.withSuppressedDiagnostics
+import org.jetbrains.kotlin.fir.declarations.FirRegularClass
+import org.jetbrains.kotlin.fir.resolve.fullyExpandedType
+import org.jetbrains.kotlin.fir.resolve.substitution.ConeSubstitutorByMap
+import org.jetbrains.kotlin.fir.symbols.impl.FirRegularClassSymbol
+import org.jetbrains.kotlin.fir.symbols.impl.FirTypeParameterSymbol
+import org.jetbrains.kotlin.fir.typeContext
+import org.jetbrains.kotlin.fir.types.*
+import org.jetbrains.kotlin.types.AbstractTypeChecker
+
+fun checkInconsistentTypeParameters(
+    firTypeRefClasses: List<Pair<FirTypeRef?, FirRegularClass>>,
+    context: CheckerContext,
+    reporter: DiagnosticReporter,
+    source: FirSourceElement?,
+    isValues: Boolean
+) {
+    val result = buildDeepSubstitutionMultimap(firTypeRefClasses, context)
+    for ((typeParameterSymbol, typeAndProjections) in result) {
+        val projections = typeAndProjections.projections
+        if (projections.size > 1) {
+            if (isValues) {
+                reporter.reportOn(
+                    source,
+                    FirErrors.INCONSISTENT_TYPE_PARAMETER_VALUES,
+                    typeParameterSymbol,
+                    typeAndProjections.classSymbol,
+                    projections,
+                    context
+                )
+            } else {
+                reporter.reportOn(
+                    source,
+                    FirErrors.INCONSISTENT_TYPE_PARAMETER_BOUNDS,
+                    typeParameterSymbol,
+                    typeAndProjections.classSymbol,
+                    projections,
+                    context
+                )
+            }
+        }
+    }
+}
+
+private fun buildDeepSubstitutionMultimap(
+    firTypeRefClasses: List<Pair<FirTypeRef?, FirRegularClass>>,
+    context: CheckerContext,
+): Map<FirTypeParameterSymbol, ClassSymbolAndProjections> {
+    val result = mutableMapOf<FirTypeParameterSymbol, ClassSymbolAndProjections>()
+    val substitution = mutableMapOf<FirTypeParameterSymbol, ConeKotlinType>()
+    val session = context.session
+    val typeContext = session.typeContext
+
+    fun fillInDeepSubstitutor(typeArguments: Array<out ConeTypeProjection>?, firClass: FirRegularClass) {
+        if (typeArguments != null) {
+            val typeParameters = firClass.typeParameters
+            val count = minOf(typeArguments.size, typeParameters.size)
+
+            for (index in 0 until count) {
+                val typeArgument = typeArguments[index]
+
+                val substitutedArgument = ConeSubstitutorByMap(substitution, session).substituteArgument(typeArgument) ?: typeArgument
+                val substitutedType = substitutedArgument.type ?: continue
+
+                val typeParameterSymbol = typeParameters[index].symbol
+
+                substitution[typeParameterSymbol] = substitutedType
+                var classSymbolAndProjections = result[typeParameterSymbol]
+                val projections: MutableList<ConeKotlinType>
+                if (classSymbolAndProjections == null) {
+                    projections = mutableListOf()
+                    classSymbolAndProjections = ClassSymbolAndProjections(firClass.symbol, projections)
+                    result[typeParameterSymbol] = classSymbolAndProjections
+                } else {
+                    projections = classSymbolAndProjections.projections
+                }
+
+                if (projections.all {
+                        it != substitutedType && !AbstractTypeChecker.equalTypes(typeContext, it, substitutedType)
+                    }) {
+                    projections.add(substitutedType)
+                }
+            }
+        }
+
+        for (superTypeRef in firClass.superTypeRefs) {
+            withSuppressedDiagnostics(superTypeRef, context) {
+                val fullyExpandedType = superTypeRef.coneType.fullyExpandedType(session)
+                val superTypeClass = fullyExpandedType.toRegularClass(session)
+                if (!fullyExpandedType.isEnum && superTypeClass != null) {
+                    fillInDeepSubstitutor(fullyExpandedType.typeArguments, superTypeClass)
+                }
+            }
+        }
+    }
+
+    for (firTypeRefClass in firTypeRefClasses) {
+        fillInDeepSubstitutor(firTypeRefClass.first?.coneType?.fullyExpandedType(session)?.typeArguments, firTypeRefClass.second)
+    }
+    return result
+}
+
+private data class ClassSymbolAndProjections(
+    val classSymbol: FirRegularClassSymbol,
+    val projections: MutableList<ConeKotlinType>
+)
\ No newline at end of file
diff --git a/compiler/fir/checkers/src/org/jetbrains/kotlin/fir/analysis/checkers/declaration/FirSupertypesChecker.kt b/compiler/fir/checkers/src/org/jetbrains/kotlin/fir/analysis/checkers/declaration/FirSupertypesChecker.kt
index 1d480ad3c7c..dab2b850731 100644
--- a/compiler/fir/checkers/src/org/jetbrains/kotlin/fir/analysis/checkers/declaration/FirSupertypesChecker.kt
+++ b/compiler/fir/checkers/src/org/jetbrains/kotlin/fir/analysis/checkers/declaration/FirSupertypesChecker.kt
@@ -7,9 +7,10 @@ package org.jetbrains.kotlin.fir.analysis.checkers.declaration
 
 import org.jetbrains.kotlin.descriptors.ClassKind
 import org.jetbrains.kotlin.descriptors.Modality
-import org.jetbrains.kotlin.fir.analysis.checkers.*
+import org.jetbrains.kotlin.fir.analysis.checkers.checkInconsistentTypeParameters
 import org.jetbrains.kotlin.fir.analysis.checkers.context.CheckerContext
 import org.jetbrains.kotlin.fir.analysis.checkers.extractTypeRefAndSourceFromTypeArgument
+import org.jetbrains.kotlin.fir.analysis.checkers.isConflictingOrNotInvariant
 import org.jetbrains.kotlin.fir.analysis.diagnostics.DiagnosticReporter
 import org.jetbrains.kotlin.fir.analysis.diagnostics.FirErrors
 import org.jetbrains.kotlin.fir.analysis.diagnostics.reportOn
@@ -21,7 +22,6 @@ import org.jetbrains.kotlin.fir.resolve.fullyExpandedType
 import org.jetbrains.kotlin.fir.resolve.toSymbol
 import org.jetbrains.kotlin.fir.symbols.impl.FirRegularClassSymbol
 import org.jetbrains.kotlin.fir.types.*
-import org.jetbrains.kotlin.name.StandardClassIds
 import org.jetbrains.kotlin.utils.addToStdlib.safeAs
 
 object FirSupertypesChecker : FirClassChecker() {
@@ -108,5 +108,9 @@ object FirSupertypesChecker : FirClassChecker() {
                 }
             }
         }
+
+        if (declaration is FirRegularClass && declaration.superTypeRefs.size > 1) {
+            checkInconsistentTypeParameters(listOf(Pair(null, declaration)), context, reporter, declaration.source, true)
+        }
     }
 }
diff --git a/compiler/fir/checkers/src/org/jetbrains/kotlin/fir/analysis/checkers/declaration/FirTypeParameterBoundsChecker.kt b/compiler/fir/checkers/src/org/jetbrains/kotlin/fir/analysis/checkers/declaration/FirTypeParameterBoundsChecker.kt
index 26eebf9e2d6..9e51dfbc26f 100644
--- a/compiler/fir/checkers/src/org/jetbrains/kotlin/fir/analysis/checkers/declaration/FirTypeParameterBoundsChecker.kt
+++ b/compiler/fir/checkers/src/org/jetbrains/kotlin/fir/analysis/checkers/declaration/FirTypeParameterBoundsChecker.kt
@@ -42,6 +42,7 @@ object FirTypeParameterBoundsChecker : FirTypeParameterChecker() {
         checkConflictingBounds(declaration, context, reporter)
         checkTypeAliasBound(declaration, containingDeclaration, context, reporter)
         checkDynamicBounds(declaration, context, reporter)
+        checkInconsistentTypeParameterBounds(declaration, context, reporter)
     }
 
     private fun checkFinalUpperBounds(
@@ -89,7 +90,7 @@ object FirTypeParameterBoundsChecker : FirTypeParameterChecker() {
             // report the diagnostic on that bound
 
             //take TypeConstraint bounds only to report on the same point as old FE
-            val constraintBounds = with(SourceNavigator.forElement(declaration)){
+            val constraintBounds = with(SourceNavigator.forElement(declaration)) {
                 bounds.filter { it.isInTypeConstraint() }.toSet()
             }
             val reportOn =
@@ -154,5 +155,29 @@ object FirTypeParameterBoundsChecker : FirTypeParameterChecker() {
     private fun KotlinTypeMarker.isRelated(context: TypeCheckerProviderContext, type: KotlinTypeMarker?): Boolean =
         isSubtypeOf(context, type) || isSupertypeOf(context, type)
 
+    private fun checkInconsistentTypeParameterBounds(
+        declaration: FirTypeParameter,
+        context: CheckerContext,
+        reporter: DiagnosticReporter
+    ) {
+        if (declaration.bounds.size <= 1) return
 
+        val firTypeRefClasses = mutableListOf<Pair<FirTypeRef, FirRegularClass>>()
+        val firRegularClassesSet = mutableSetOf<FirRegularClass>()
+
+        for (bound in declaration.bounds) {
+            val firRegularClass = bound.toRegularClass(context.session)
+            if (firRegularClassesSet.contains(firRegularClass)) {
+                // no need to throw INCONSISTENT_TYPE_PARAMETER_BOUNDS diagnostics here because REPEATED_BOUNDS diagnostic is already exist
+                return
+            }
+
+            if (firRegularClass != null) {
+                firRegularClassesSet.add(firRegularClass)
+                firTypeRefClasses.add(Pair(bound, firRegularClass))
+            }
+        }
+
+        checkInconsistentTypeParameters(firTypeRefClasses, context, reporter, declaration.source, false)
+    }
 }
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 3b4b87d5dd9..21f2de51d0f 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
@@ -19,6 +19,7 @@ import org.jetbrains.kotlin.fir.analysis.diagnostics.FirDiagnosticRenderers.REND
 import org.jetbrains.kotlin.fir.analysis.diagnostics.FirDiagnosticRenderers.RENDER_TYPE
 import org.jetbrains.kotlin.fir.analysis.diagnostics.FirDiagnosticRenderers.SYMBOL
 import org.jetbrains.kotlin.fir.analysis.diagnostics.FirDiagnosticRenderers.SYMBOLS
+import org.jetbrains.kotlin.fir.analysis.diagnostics.FirDiagnosticRenderers.RENDER_COLLECTION_OF_TYPES
 import org.jetbrains.kotlin.fir.analysis.diagnostics.FirDiagnosticRenderers.TO_STRING
 import org.jetbrains.kotlin.fir.analysis.diagnostics.FirDiagnosticRenderers.VARIABLE_NAME
 import org.jetbrains.kotlin.fir.analysis.diagnostics.FirDiagnosticRenderers.VISIBILITY
@@ -171,6 +172,8 @@ import org.jetbrains.kotlin.fir.analysis.diagnostics.FirErrors.INCOMPATIBLE_ENUM
 import org.jetbrains.kotlin.fir.analysis.diagnostics.FirErrors.INCOMPATIBLE_MODIFIERS
 import org.jetbrains.kotlin.fir.analysis.diagnostics.FirErrors.INCOMPATIBLE_TYPES
 import org.jetbrains.kotlin.fir.analysis.diagnostics.FirErrors.INCOMPATIBLE_TYPES_WARNING
+import org.jetbrains.kotlin.fir.analysis.diagnostics.FirErrors.INCONSISTENT_TYPE_PARAMETER_BOUNDS
+import org.jetbrains.kotlin.fir.analysis.diagnostics.FirErrors.INCONSISTENT_TYPE_PARAMETER_VALUES
 import org.jetbrains.kotlin.fir.analysis.diagnostics.FirErrors.INFERENCE_ERROR
 import org.jetbrains.kotlin.fir.analysis.diagnostics.FirErrors.INFIX_MODIFIER_REQUIRED
 import org.jetbrains.kotlin.fir.analysis.diagnostics.FirErrors.INITIALIZER_REQUIRED_FOR_DESTRUCTURING_DECLARATION
@@ -466,6 +469,20 @@ class FirDefaultErrorMessages {
                 RENDER_TYPE
             )
             map.put(PROJECTION_IN_IMMEDIATE_ARGUMENT_TO_SUPERTYPE, "Projections are not allowed for immediate arguments of a supertype")
+            map.put(
+                INCONSISTENT_TYPE_PARAMETER_VALUES,
+                "Type parameter {0} of ''{1}'' has inconsistent values: {2}",
+                SYMBOL,
+                SYMBOL,
+                RENDER_COLLECTION_OF_TYPES
+            )
+            map.put(
+                INCONSISTENT_TYPE_PARAMETER_BOUNDS,
+                "Type parameter {0} of ''{1}'' has inconsistent bounds: {2}",
+                SYMBOL,
+                SYMBOL,
+                RENDER_COLLECTION_OF_TYPES
+            )
 
             // Constructor problems
             map.put(CONSTRUCTOR_IN_OBJECT, "Constructors are not allowed for objects")
diff --git a/compiler/fir/checkers/src/org/jetbrains/kotlin/fir/analysis/diagnostics/FirDiagnosticRenderers.kt b/compiler/fir/checkers/src/org/jetbrains/kotlin/fir/analysis/diagnostics/FirDiagnosticRenderers.kt
index 7b65f23e562..9eac0190297 100644
--- a/compiler/fir/checkers/src/org/jetbrains/kotlin/fir/analysis/diagnostics/FirDiagnosticRenderers.kt
+++ b/compiler/fir/checkers/src/org/jetbrains/kotlin/fir/analysis/diagnostics/FirDiagnosticRenderers.kt
@@ -38,6 +38,12 @@ object FirDiagnosticRenderers {
         }
     }
 
+    val RENDER_COLLECTION_OF_TYPES = Renderer { types: Collection<ConeKotlinType> ->
+        types.joinToString(separator = ", ") { type ->
+            RENDER_TYPE.render(type)
+        }
+    }
+
     val TO_STRING = Renderer { element: Any? ->
         element.toString()
     }
diff --git a/compiler/testData/diagnostics/tests/GenericArgumentConsistency.fir.kt b/compiler/testData/diagnostics/tests/GenericArgumentConsistency.fir.kt
deleted file mode 100644
index 2d50e8c8fd3..00000000000
--- a/compiler/testData/diagnostics/tests/GenericArgumentConsistency.fir.kt
+++ /dev/null
@@ -1,43 +0,0 @@
-// FILE: a.kt
-interface A<in T> {}
-interface B<T> : A<Int> {}
-interface C<T> : B<T>, A<T> {}
-interface C1<T> : B<T>, A<Any> {}
-interface D : C<Boolean>, B<Double>{}
-
-interface A1<out T> {}
-interface B1 : A1<Int> {}
-interface B2 : A1<Any>, B1 {}
-
-interface BA1<T> {}
-interface BB1 : BA1<Int> {}
-interface BB2 : BA1<Any>, BB1 {}
-
-
-// FILE: b.kt
-package x
-    interface AA1<out T> {}
-    interface AB1 : AA1<Int> {}
-    interface AB3 : AA1<Comparable<Int>> {}
-    interface AB2 : AA1<Number>, AB1, AB3 {}
-
-// FILE: c.kt
-package x2
-    interface AA1<out T> {}
-    interface AB1 : AA1<Any> {}
-    interface AB3 : AA1<Comparable<Int>> {}
-    interface AB2 : AA1<Number>, AB1, AB3 {}
-
-// FILE: d.kt
-package x3
-    interface AA1<in T> {}
-    interface AB1 : AA1<Any> {}
-    interface AB3 : AA1<Comparable<Int>> {}
-    interface AB2 : AA1<Number>, AB1, AB3 {}
-
-// FILE: e.kt
-package sx2
-    interface AA1<in T> {}
-    interface AB1 : AA1<Int> {}
-    interface AB3 : AA1<Comparable<Int>> {}
-    interface AB2 : AA1<Number>, AB1, AB3 {}
diff --git a/compiler/testData/diagnostics/tests/GenericArgumentConsistency.kt b/compiler/testData/diagnostics/tests/GenericArgumentConsistency.kt
index a9c4557b742..bb5d98915e5 100644
--- a/compiler/testData/diagnostics/tests/GenericArgumentConsistency.kt
+++ b/compiler/testData/diagnostics/tests/GenericArgumentConsistency.kt
@@ -1,3 +1,4 @@
+// FIR_IDENTICAL
 // FILE: a.kt
 interface A<in T> {}
 interface B<T> : A<Int> {}
@@ -16,28 +17,36 @@ interface BB2 : <!INCONSISTENT_TYPE_PARAMETER_VALUES!>BA1<Any>, BB1<!> {}
 
 // FILE: b.kt
 package x
-    interface AA1<out T> {}
-    interface AB1 : AA1<Int> {}
-    interface AB3 : AA1<Comparable<Int>> {}
-    interface AB2 : <!INCONSISTENT_TYPE_PARAMETER_VALUES!>AA1<Number>, AB1, AB3<!> {}
+interface AA1<out T> {}
+interface AB1 : AA1<Int> {}
+interface AB3 : AA1<Comparable<Int>> {}
+interface AB2 : <!INCONSISTENT_TYPE_PARAMETER_VALUES!>AA1<Number>, AB1, AB3<!> {}
 
 // FILE: c.kt
 package x2
-    interface AA1<out T> {}
-    interface AB1 : AA1<Any> {}
-    interface AB3 : AA1<Comparable<Int>> {}
-    interface AB2 : <!INCONSISTENT_TYPE_PARAMETER_VALUES!>AA1<Number>, AB1, AB3<!> {}
+interface AA1<out T> {}
+interface AB1 : AA1<Any> {}
+interface AB3 : AA1<Comparable<Int>> {}
+interface AB2 : <!INCONSISTENT_TYPE_PARAMETER_VALUES!>AA1<Number>, AB1, AB3<!> {}
 
 // FILE: d.kt
 package x3
-    interface AA1<in T> {}
-    interface AB1 : AA1<Any> {}
-    interface AB3 : AA1<Comparable<Int>> {}
-    interface AB2 : <!INCONSISTENT_TYPE_PARAMETER_VALUES!>AA1<Number>, AB1, AB3<!> {}
+interface AA1<in T> {}
+interface AB1 : AA1<Any> {}
+interface AB3 : AA1<Comparable<Int>> {}
+interface AB2 : <!INCONSISTENT_TYPE_PARAMETER_VALUES!>AA1<Number>, AB1, AB3<!> {}
 
 // FILE: e.kt
 package sx2
-    interface AA1<in T> {}
-    interface AB1 : AA1<Int> {}
-    interface AB3 : AA1<Comparable<Int>> {}
-    interface AB2 : <!INCONSISTENT_TYPE_PARAMETER_VALUES!>AA1<Number>, AB1, AB3<!> {}
+interface AA1<in T> {}
+interface AB1 : AA1<Int> {}
+interface AB3 : AA1<Comparable<Int>> {}
+interface AB2 : <!INCONSISTENT_TYPE_PARAMETER_VALUES!>AA1<Number>, AB1, AB3<!> {}
+
+// FILE: f.kt
+interface I0<T1, T2>
+abstract class C2<T3, T4> : I0<T3, T4>
+typealias TA<T5, T6> = C2<T6, T5>
+interface I2
+interface I3
+class C3 : TA<I2, I3>(), I0<I3, I2>
\ No newline at end of file
diff --git a/compiler/testData/diagnostics/tests/GenericArgumentConsistency.txt b/compiler/testData/diagnostics/tests/GenericArgumentConsistency.txt
index 87581f389ea..262b2c79f62 100644
--- a/compiler/testData/diagnostics/tests/GenericArgumentConsistency.txt
+++ b/compiler/testData/diagnostics/tests/GenericArgumentConsistency.txt
@@ -60,12 +60,45 @@ public interface C1</*0*/ T> : B<T>, A<kotlin.Any> {
     public open override /*2*/ /*fake_override*/ fun toString(): kotlin.String
 }
 
+public abstract class C2</*0*/ T3, /*1*/ T4> : I0<T3, T4> {
+    public constructor C2</*0*/ T3, /*1*/ T4>()
+    public open override /*1*/ /*fake_override*/ fun equals(/*0*/ other: kotlin.Any?): kotlin.Boolean
+    public open override /*1*/ /*fake_override*/ fun hashCode(): kotlin.Int
+    public open override /*1*/ /*fake_override*/ fun toString(): kotlin.String
+}
+
+public final class C3 : TA<I2, I3> /* = C2<I3, I2> */, I0<I3, I2> {
+    public constructor C3()
+    public open override /*2*/ /*fake_override*/ fun equals(/*0*/ other: kotlin.Any?): kotlin.Boolean
+    public open override /*2*/ /*fake_override*/ fun hashCode(): kotlin.Int
+    public open override /*2*/ /*fake_override*/ fun toString(): kotlin.String
+}
+
 public interface D : C<kotlin.Boolean>, B<kotlin.Double> {
     public open override /*2*/ /*fake_override*/ fun equals(/*0*/ other: kotlin.Any?): kotlin.Boolean
     public open override /*2*/ /*fake_override*/ fun hashCode(): kotlin.Int
     public open override /*2*/ /*fake_override*/ fun toString(): kotlin.String
 }
 
+public interface I0</*0*/ T1, /*1*/ T2> {
+    public open override /*1*/ /*fake_override*/ fun equals(/*0*/ other: kotlin.Any?): kotlin.Boolean
+    public open override /*1*/ /*fake_override*/ fun hashCode(): kotlin.Int
+    public open override /*1*/ /*fake_override*/ fun toString(): kotlin.String
+}
+
+public interface I2 {
+    public open override /*1*/ /*fake_override*/ fun equals(/*0*/ other: kotlin.Any?): kotlin.Boolean
+    public open override /*1*/ /*fake_override*/ fun hashCode(): kotlin.Int
+    public open override /*1*/ /*fake_override*/ fun toString(): kotlin.String
+}
+
+public interface I3 {
+    public open override /*1*/ /*fake_override*/ fun equals(/*0*/ other: kotlin.Any?): kotlin.Boolean
+    public open override /*1*/ /*fake_override*/ fun hashCode(): kotlin.Int
+    public open override /*1*/ /*fake_override*/ fun toString(): kotlin.String
+}
+public typealias TA</*0*/ T5, /*1*/ T6> = C2<T6, T5>
+
 package sx2 {
 
     public interface AA1</*0*/ in T> {
@@ -173,3 +206,4 @@ package x3 {
         public open override /*1*/ /*fake_override*/ fun toString(): kotlin.String
     }
 }
+
diff --git a/compiler/testData/diagnostics/tests/cast/IsErasedAllowForTypeWithIrrelevantMixin.fir.kt b/compiler/testData/diagnostics/tests/cast/IsErasedAllowForTypeWithIrrelevantMixin.fir.kt
deleted file mode 100644
index f69dc7a1aaf..00000000000
--- a/compiler/testData/diagnostics/tests/cast/IsErasedAllowForTypeWithIrrelevantMixin.fir.kt
+++ /dev/null
@@ -1,9 +0,0 @@
-interface A
-interface B: A
-interface D
-
-interface BaseSuper<out T>
-interface BaseImpl: BaseSuper<D>
-interface DerivedSuper<out S>: BaseSuper<S>, BaseImpl
-
-fun test(t: BaseSuper<B>) = t is DerivedSuper<A>
\ No newline at end of file
diff --git a/compiler/testData/diagnostics/tests/cast/IsErasedAllowForTypeWithIrrelevantMixin.kt b/compiler/testData/diagnostics/tests/cast/IsErasedAllowForTypeWithIrrelevantMixin.kt
index 296ae7582aa..2fe07a78dc0 100644
--- a/compiler/testData/diagnostics/tests/cast/IsErasedAllowForTypeWithIrrelevantMixin.kt
+++ b/compiler/testData/diagnostics/tests/cast/IsErasedAllowForTypeWithIrrelevantMixin.kt
@@ -1,3 +1,4 @@
+// FIR_IDENTICAL
 interface A
 interface B: A
 interface D
diff --git a/compiler/testData/diagnostics/tests/generics/InconsistentTypeParameterBounds.fir.kt b/compiler/testData/diagnostics/tests/generics/InconsistentTypeParameterBounds.fir.kt
deleted file mode 100644
index e6f3a6df42c..00000000000
--- a/compiler/testData/diagnostics/tests/generics/InconsistentTypeParameterBounds.fir.kt
+++ /dev/null
@@ -1,7 +0,0 @@
-interface A
-interface B : A
-
-interface ListA : List<A>
-interface ListB : List<B>
-
-interface Z<T> where T : ListA, T : ListB
diff --git a/compiler/testData/diagnostics/tests/generics/InconsistentTypeParameterBounds.kt b/compiler/testData/diagnostics/tests/generics/InconsistentTypeParameterBounds.kt
index 71dc57aa668..74e687e8307 100644
--- a/compiler/testData/diagnostics/tests/generics/InconsistentTypeParameterBounds.kt
+++ b/compiler/testData/diagnostics/tests/generics/InconsistentTypeParameterBounds.kt
@@ -1,3 +1,4 @@
+// FIR_IDENTICAL
 interface A
 interface B : A
 
diff --git a/compiler/testData/diagnostics/tests/override/clashesOnInheritance/unrelatedInherited.fir.kt b/compiler/testData/diagnostics/tests/override/clashesOnInheritance/unrelatedInherited.fir.kt
deleted file mode 100644
index c8b6efc9e1d..00000000000
--- a/compiler/testData/diagnostics/tests/override/clashesOnInheritance/unrelatedInherited.fir.kt
+++ /dev/null
@@ -1,33 +0,0 @@
-interface IA {
-    fun method(): String
-    val propVal: String
-    var propVar: String
-}
-
-interface IB1 : IA
-interface IB2 : IA
-
-interface IGA<T> {
-    fun method(): T
-    val propVal: T
-    var propVar: T
-}
-
-interface IGB1Str : IGA<String>
-interface IGB2Str : IGA<String>
-interface IGB3Int : IGA<Int>
-
-interface IGB4T<T> : IGA<T>
-interface IGB5T<T> : IGA<T>
-
-interface IC : IB1, IB2
-
-interface IGC1 : IGB1Str, IGB2Str
-
-interface IGC2 : IGB1Str, IGB3Int
-
-interface IGC3<T> : IGB4T<T>, IGB5T<T>
-
-interface IGC4<T> : IGB4T<T>, IGB5T<String>
-
-interface IGC5 : IGB4T<String>, IGB5T<String>
\ No newline at end of file
diff --git a/compiler/testData/diagnostics/tests/override/clashesOnInheritance/unrelatedInherited.kt b/compiler/testData/diagnostics/tests/override/clashesOnInheritance/unrelatedInherited.kt
index 3e6fb0ded2b..5002e80f382 100644
--- a/compiler/testData/diagnostics/tests/override/clashesOnInheritance/unrelatedInherited.kt
+++ b/compiler/testData/diagnostics/tests/override/clashesOnInheritance/unrelatedInherited.kt
@@ -1,3 +1,4 @@
+// FIR_IDENTICAL
 interface IA {
     fun method(): String
     val propVal: String
diff --git a/compiler/testData/diagnostics/tests/subtyping/findClosestCorrespondingSupertype.fir.kt b/compiler/testData/diagnostics/tests/subtyping/findClosestCorrespondingSupertype.fir.kt
index f42d97e3c21..be4c844abff 100644
--- a/compiler/testData/diagnostics/tests/subtyping/findClosestCorrespondingSupertype.fir.kt
+++ b/compiler/testData/diagnostics/tests/subtyping/findClosestCorrespondingSupertype.fir.kt
@@ -2,7 +2,7 @@
 
 interface X<T>
 interface A: X<String>
-interface B : A, X<Int>
+interface B : <!INCONSISTENT_TYPE_PARAMETER_VALUES!>A, X<Int><!>
 
 fun foo(x: B) {
     // Checks that when checking subtypes we search closes corresponding constructor (e.g. with BFS)
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 70b84fd9950..a750799be59 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
@@ -425,6 +425,28 @@ internal val KT_DIAGNOSTIC_CONVERTER = KtDiagnosticConverterBuilder.buildConvert
             token,
         )
     }
+    add(FirErrors.INCONSISTENT_TYPE_PARAMETER_VALUES) { firDiagnostic ->
+        InconsistentTypeParameterValuesImpl(
+            firSymbolBuilder.classifierBuilder.buildTypeParameterSymbol(firDiagnostic.a.fir),
+            firSymbolBuilder.classifierBuilder.buildClassLikeSymbol(firDiagnostic.b.fir),
+            firDiagnostic.c.map { coneKotlinType ->
+                firSymbolBuilder.typeBuilder.buildKtType(coneKotlinType)
+            },
+            firDiagnostic as FirPsiDiagnostic,
+            token,
+        )
+    }
+    add(FirErrors.INCONSISTENT_TYPE_PARAMETER_BOUNDS) { firDiagnostic ->
+        InconsistentTypeParameterBoundsImpl(
+            firSymbolBuilder.classifierBuilder.buildTypeParameterSymbol(firDiagnostic.a.fir),
+            firSymbolBuilder.classifierBuilder.buildClassLikeSymbol(firDiagnostic.b.fir),
+            firDiagnostic.c.map { coneKotlinType ->
+                firSymbolBuilder.typeBuilder.buildKtType(coneKotlinType)
+            },
+            firDiagnostic as FirPsiDiagnostic,
+            token,
+        )
+    }
     add(FirErrors.CONSTRUCTOR_IN_OBJECT) { firDiagnostic ->
         ConstructorInObjectImpl(
             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 ed7c8c5bf0a..2490e85ef8b 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
@@ -316,6 +316,20 @@ sealed class KtFirDiagnostic<PSI: PsiElement> : KtDiagnosticWithPsi<PSI> {
         override val diagnosticClass get() = ProjectionInImmediateArgumentToSupertype::class
     }
 
+    abstract class InconsistentTypeParameterValues : KtFirDiagnostic<KtClass>() {
+        override val diagnosticClass get() = InconsistentTypeParameterValues::class
+        abstract val typeParameter: KtTypeParameterSymbol
+        abstract val type: KtClassLikeSymbol
+        abstract val bounds: List<KtType>
+    }
+
+    abstract class InconsistentTypeParameterBounds : KtFirDiagnostic<PsiElement>() {
+        override val diagnosticClass get() = InconsistentTypeParameterBounds::class
+        abstract val typeParameter: KtTypeParameterSymbol
+        abstract val type: KtClassLikeSymbol
+        abstract val bounds: List<KtType>
+    }
+
     abstract class ConstructorInObject : KtFirDiagnostic<KtDeclaration>() {
         override val diagnosticClass get() = ConstructorInObject::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 5cda196cd7a..4413bf62ab9 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
@@ -494,6 +494,26 @@ internal class ProjectionInImmediateArgumentToSupertypeImpl(
     override val firDiagnostic: FirPsiDiagnostic by weakRef(firDiagnostic)
 }
 
+internal class InconsistentTypeParameterValuesImpl(
+    override val typeParameter: KtTypeParameterSymbol,
+    override val type: KtClassLikeSymbol,
+    override val bounds: List<KtType>,
+    firDiagnostic: FirPsiDiagnostic,
+    override val token: ValidityToken,
+) : KtFirDiagnostic.InconsistentTypeParameterValues(), KtAbstractFirDiagnostic<KtClass> {
+    override val firDiagnostic: FirPsiDiagnostic by weakRef(firDiagnostic)
+}
+
+internal class InconsistentTypeParameterBoundsImpl(
+    override val typeParameter: KtTypeParameterSymbol,
+    override val type: KtClassLikeSymbol,
+    override val bounds: List<KtType>,
+    firDiagnostic: FirPsiDiagnostic,
+    override val token: ValidityToken,
+) : KtFirDiagnostic.InconsistentTypeParameterBounds(), KtAbstractFirDiagnostic<PsiElement> {
+    override val firDiagnostic: FirPsiDiagnostic by weakRef(firDiagnostic)
+}
+
 internal class ConstructorInObjectImpl(
     firDiagnostic: FirPsiDiagnostic,
     override val token: ValidityToken,
diff --git a/idea/testData/checker/GenericArgumentConsistency.fir.kt b/idea/testData/checker/GenericArgumentConsistency.fir.kt
index 2658e33e8c8..edd786620ca 100644
--- a/idea/testData/checker/GenericArgumentConsistency.fir.kt
+++ b/idea/testData/checker/GenericArgumentConsistency.fir.kt
@@ -1,42 +1,42 @@
 interface A<in T> {}
 interface B<T> : A<Int> {}
-interface C<T> : B<T>, A<T> {}
-interface C1<T> : B<T>, A<Any> {}
-interface D : C<Boolean>, B<Double>{}
+interface C<T> : <error descr="[INCONSISTENT_TYPE_PARAMETER_VALUES] Type parameter T of 'A' has inconsistent values: kotlin/Int, T">B<T>, A<T></error> {}
+interface C1<T> : <error descr="[INCONSISTENT_TYPE_PARAMETER_VALUES] Type parameter T of 'A' has inconsistent values: kotlin/Int, kotlin/Any">B<T>, A<Any></error> {}
+interface D : <error descr="[INCONSISTENT_TYPE_PARAMETER_VALUES] Type parameter T of 'A' has inconsistent values: kotlin/Int, kotlin/Boolean"><error descr="[INCONSISTENT_TYPE_PARAMETER_VALUES] Type parameter T of 'B' has inconsistent values: kotlin/Boolean, kotlin/Double">C<Boolean>, B<Double></error></error>{}
 
 interface A1<out T> {}
 interface B1 : A1<Int> {}
-interface B2 : A1<Any>, B1 {}
+interface B2 : <error descr="[INCONSISTENT_TYPE_PARAMETER_VALUES] Type parameter T of 'A1' has inconsistent values: kotlin/Any, kotlin/Int">A1<Any>, B1</error> {}
 
 interface BA1<T> {}
 interface BB1 : BA1<Int> {}
-interface BB2 : BA1<Any>, BB1 {}
+interface BB2 : <error descr="[INCONSISTENT_TYPE_PARAMETER_VALUES] Type parameter T of 'BA1' has inconsistent values: kotlin/Any, kotlin/Int">BA1<Any>, BB1</error> {}
 
 
 //package x {
     interface xAA1<out T> {}
     interface xAB1 : xAA1<Int> {}
     interface xAB3 : xAA1<Comparable<Int>> {}
-    interface xAB2 : xAA1<Number>, xAB1, xAB3 {}
+    interface xAB2 : <error descr="[INCONSISTENT_TYPE_PARAMETER_VALUES] Type parameter T of 'xAA1' has inconsistent values: kotlin/Number, kotlin/Int, kotlin/Comparable<kotlin/Int>">xAA1<Number>, xAB1, xAB3</error> {}
 //}
 
 //package x2 {
     interface x2AA1<out T> {}
     interface x2AB1 : x2AA1<Any> {}
     interface x2AB3 : x2AA1<Comparable<Int>> {}
-    interface x2AB2 : x2AA1<Number>, x2AB1, x2AB3 {}
+    interface x2AB2 : <error descr="[INCONSISTENT_TYPE_PARAMETER_VALUES] Type parameter T of 'x2AA1' has inconsistent values: kotlin/Number, kotlin/Any, kotlin/Comparable<kotlin/Int>">x2AA1<Number>, x2AB1, x2AB3</error> {}
 //}
 
 //package x3 {
     interface x3AA1<in T> {}
     interface x3AB1 : x3AA1<Any> {}
     interface x3AB3 : x3AA1<Comparable<Int>> {}
-    interface x3AB2 : x3AA1<Number>, x3AB1, x3AB3 {}
+    interface x3AB2 : <error descr="[INCONSISTENT_TYPE_PARAMETER_VALUES] Type parameter T of 'x3AA1' has inconsistent values: kotlin/Number, kotlin/Any, kotlin/Comparable<kotlin/Int>">x3AA1<Number>, x3AB1, x3AB3</error> {}
 //}
 
 //package sx2 {
     interface sx2AA1<in T> {}
     interface sx2AB1 : sx2AA1<Int> {}
     interface sx2AB3 : sx2AA1<Comparable<Int>> {}
-    interface sx2AB2 : sx2AA1<Number>, sx2AB1, sx2AB3 {}
+    interface sx2AB2 : <error descr="[INCONSISTENT_TYPE_PARAMETER_VALUES] Type parameter T of 'sx2AA1' has inconsistent values: kotlin/Number, kotlin/Int, kotlin/Comparable<kotlin/Int>">sx2AA1<Number>, sx2AB1, sx2AB3</error> {}
 //}