diff --git a/compiler/fir/resolve/src/org/jetbrains/kotlin/fir/resolve/inference/FirBuilderInferenceSession.kt b/compiler/fir/resolve/src/org/jetbrains/kotlin/fir/resolve/inference/FirBuilderInferenceSession.kt
index e69a0552eee..0ecdb3e83df 100644
--- a/compiler/fir/resolve/src/org/jetbrains/kotlin/fir/resolve/inference/FirBuilderInferenceSession.kt
+++ b/compiler/fir/resolve/src/org/jetbrains/kotlin/fir/resolve/inference/FirBuilderInferenceSession.kt
@@ -17,6 +17,7 @@ import org.jetbrains.kotlin.fir.resolve.calls.ImplicitExtensionReceiverValue
 import org.jetbrains.kotlin.fir.resolve.calls.ResolutionContext
 import org.jetbrains.kotlin.fir.resolve.substitution.ChainedSubstitutor
 import org.jetbrains.kotlin.fir.resolve.substitution.ConeSubstitutor
+import org.jetbrains.kotlin.fir.resolve.substitution.replaceStubsAndTypeVariablesToErrors
 import org.jetbrains.kotlin.fir.types.*
 import org.jetbrains.kotlin.fir.visitors.FirDefaultTransformer
 import org.jetbrains.kotlin.fir.visitors.transformSingle
@@ -127,7 +128,6 @@ class FirBuilderInferenceSession(
         }
 
         val context = commonSystem.asConstraintSystemCompleterContext()
-        @Suppress("UNCHECKED_CAST")
         components.callCompleter.completer.complete(
             context,
             completionMode,
@@ -230,10 +230,11 @@ class FirBuilderInferenceSession(
         return introducedConstraint
     }
 
-    private fun getResultingSubstitutor(commonSystem: NewConstraintSystemImpl): ChainedSubstitutor {
+    private fun getResultingSubstitutor(commonSystem: NewConstraintSystemImpl): ConeSubstitutor {
         val nonFixedToVariablesSubstitutor = createNonFixedTypeToVariableSubstitutor()
         val commonSystemSubstitutor = commonSystem.buildCurrentSubstitutor() as ConeSubstitutor
         return ChainedSubstitutor(nonFixedToVariablesSubstitutor, commonSystemSubstitutor)
+            .replaceStubsAndTypeVariablesToErrors(resolutionContext.typeContext, stubsForPostponedVariables.values.map { it.constructor })
     }
 
     private fun updateCalls(substitutor: ConeSubstitutor) {