diff --git a/compiler/fir/resolve/src/org/jetbrains/kotlin/fir/resolve/calls/CreateFreshTypeVariableSubstitutorStage.kt b/compiler/fir/resolve/src/org/jetbrains/kotlin/fir/resolve/calls/CreateFreshTypeVariableSubstitutorStage.kt
index dec894a712a..8a989673eb2 100644
--- a/compiler/fir/resolve/src/org/jetbrains/kotlin/fir/resolve/calls/CreateFreshTypeVariableSubstitutorStage.kt
+++ b/compiler/fir/resolve/src/org/jetbrains/kotlin/fir/resolve/calls/CreateFreshTypeVariableSubstitutorStage.kt
@@ -16,6 +16,7 @@ import org.jetbrains.kotlin.fir.symbols.invoke
 import org.jetbrains.kotlin.fir.types.*
 import org.jetbrains.kotlin.fir.types.impl.FirTypePlaceholderProjection
 import org.jetbrains.kotlin.resolve.calls.inference.ConstraintSystemOperation
+import org.jetbrains.kotlin.resolve.calls.inference.model.FirDeclaredUpperBoundConstraintPosition
 import org.jetbrains.kotlin.resolve.calls.inference.model.SimpleConstraintSystemConstraintPosition
 
 
@@ -102,7 +103,7 @@ fun createToFreshVariableSubstitutorAndAddInitialConstraints(
         upperBound: ConeKotlinType//,
         //position: DeclaredUpperBoundConstraintPosition
     ) {
-        csBuilder.addSubtypeConstraint(defaultType, toFreshVariables.substituteOrSelf(upperBound), SimpleConstraintSystemConstraintPosition)
+        csBuilder.addSubtypeConstraint(defaultType, toFreshVariables.substituteOrSelf(upperBound), FirDeclaredUpperBoundConstraintPosition())
     }
 
     for (index in typeParameters.indices) {
diff --git a/compiler/resolution/src/org/jetbrains/kotlin/resolve/calls/components/ResolutionParts.kt b/compiler/resolution/src/org/jetbrains/kotlin/resolve/calls/components/ResolutionParts.kt
index 21cccd8f036..1643a07249b 100644
--- a/compiler/resolution/src/org/jetbrains/kotlin/resolve/calls/components/ResolutionParts.kt
+++ b/compiler/resolution/src/org/jetbrains/kotlin/resolve/calls/components/ResolutionParts.kt
@@ -13,10 +13,7 @@ import org.jetbrains.kotlin.descriptors.impl.TypeAliasConstructorDescriptor
 import org.jetbrains.kotlin.resolve.calls.components.TypeArgumentsToParametersMapper.TypeArgumentsMapping.NoExplicitArguments
 import org.jetbrains.kotlin.resolve.calls.inference.ConstraintSystemOperation
 import org.jetbrains.kotlin.resolve.calls.inference.components.FreshVariableNewTypeSubstitutor
-import org.jetbrains.kotlin.resolve.calls.inference.model.DeclaredUpperBoundConstraintPosition
-import org.jetbrains.kotlin.resolve.calls.inference.model.ExplicitTypeParameterConstraintPosition
-import org.jetbrains.kotlin.resolve.calls.inference.model.KnownTypeParameterConstraintPosition
-import org.jetbrains.kotlin.resolve.calls.inference.model.TypeVariableFromCallableDescriptor
+import org.jetbrains.kotlin.resolve.calls.inference.model.*
 import org.jetbrains.kotlin.resolve.calls.inference.substitute
 import org.jetbrains.kotlin.resolve.calls.model.*
 import org.jetbrains.kotlin.resolve.calls.smartcasts.getReceiverValueWithSmartCast
@@ -197,7 +194,7 @@ internal object CreateFreshVariablesSubstitutor : ResolutionPart() {
         for (index in typeParameters.indices) {
             val typeParameter = typeParameters[index]
             val freshVariable = freshTypeVariables[index]
-            val position = DeclaredUpperBoundConstraintPosition(typeParameter)
+            val position = DeclaredUpperBoundConstraintPositionImpl(typeParameter)
 
             for (upperBound in typeParameter.upperBounds) {
                 freshVariable.addSubtypeConstraint(upperBound, position)
@@ -218,7 +215,7 @@ internal object CreateFreshVariablesSubstitutor : ResolutionPart() {
                     // there can be null in case we already captured type parameter in outer class (in case of inner classes)
                     // see test innerClassTypeAliasConstructor.kt
                     val originalTypeParameter = originalTypeParameters.getOrNull(originalIndex) ?: continue
-                    val position = DeclaredUpperBoundConstraintPosition(originalTypeParameter)
+                    val position = DeclaredUpperBoundConstraintPositionImpl(originalTypeParameter)
                     for (upperBound in originalTypeParameter.upperBounds) {
                         freshVariable.addSubtypeConstraint(upperBound, position)
                     }
diff --git a/compiler/resolution/src/org/jetbrains/kotlin/resolve/calls/inference/model/ConstraintPositionAndErrors.kt b/compiler/resolution/src/org/jetbrains/kotlin/resolve/calls/inference/model/ConstraintPositionAndErrors.kt
index f93d5e43cf2..7dd616fcd14 100644
--- a/compiler/resolution/src/org/jetbrains/kotlin/resolve/calls/inference/model/ConstraintPositionAndErrors.kt
+++ b/compiler/resolution/src/org/jetbrains/kotlin/resolve/calls/inference/model/ConstraintPositionAndErrors.kt
@@ -37,10 +37,14 @@ class ExpectedTypeConstraintPosition(val topLevelCall: KotlinCall) : ConstraintP
     override fun toString() = "ExpectedType for call $topLevelCall"
 }
 
-class DeclaredUpperBoundConstraintPosition(val typeParameterDescriptor: TypeParameterDescriptor) : ConstraintPosition() {
+sealed class DeclaredUpperBoundConstraintPosition : ConstraintPosition()
+
+class DeclaredUpperBoundConstraintPositionImpl(val typeParameterDescriptor: TypeParameterDescriptor) : DeclaredUpperBoundConstraintPosition() {
     override fun toString() = "DeclaredUpperBound ${typeParameterDescriptor.name} from ${typeParameterDescriptor.containingDeclaration}"
 }
 
+class FirDeclaredUpperBoundConstraintPosition : DeclaredUpperBoundConstraintPosition()
+
 class ArgumentConstraintPosition(val argument: KotlinCallArgument) : ConstraintPosition() {
     override fun toString() = "Argument $argument"
 }