diff --git a/compiler/frontend.java/src/org/jetbrains/kotlin/resolve/jvm/kotlinSignature/SignaturesPropagationData.java b/compiler/frontend.java/src/org/jetbrains/kotlin/resolve/jvm/kotlinSignature/SignaturesPropagationData.java
index a46a4f9f719..7d3ba4e211b 100644
--- a/compiler/frontend.java/src/org/jetbrains/kotlin/resolve/jvm/kotlinSignature/SignaturesPropagationData.java
+++ b/compiler/frontend.java/src/org/jetbrains/kotlin/resolve/jvm/kotlinSignature/SignaturesPropagationData.java
@@ -526,7 +526,7 @@ public class SignaturesPropagationData {
         // #1 of Baz ->  A
         // #0 of Foo ->  A (mapped to itself)
         // #1 of Foo ->  B (mapped to itself)
-        Multimap<TypeConstructor, TypeProjection> substitution = SubstitutionUtils.buildDeepSubstitutionMultimap(
+        Multimap<TypeParameterDescriptor, TypeProjection> substitution = SubstitutionUtils.buildDeepSubstitutionMultimap(
                 TypeUtils.makeUnsubstitutedType(klass, ErrorUtils.createErrorScope("Do not access this scope", true)));
 
         // for each parameter of klass, hold arguments in corresponding supertypes
@@ -547,7 +547,7 @@ public class SignaturesPropagationData {
                 // 4. typeFromSuper = Baz<Boolean, CharSequence>,  parameter = "#1 of Baz",  argument = CharSequence
 
                 // if it is mapped to klass' parameter, then store it into map
-                for (TypeProjection projection : substitution.get(parameter.getTypeConstructor())) {
+                for (TypeProjection projection : substitution.get(parameter)) {
                     // 1. projection = A
                     // 2. projection = List<B>
                     // 3. projection = Boolean
diff --git a/compiler/frontend/src/org/jetbrains/kotlin/resolve/DeclarationsChecker.java b/compiler/frontend/src/org/jetbrains/kotlin/resolve/DeclarationsChecker.java
index bfa725014f2..8cb5f10ae9d 100644
--- a/compiler/frontend/src/org/jetbrains/kotlin/resolve/DeclarationsChecker.java
+++ b/compiler/frontend/src/org/jetbrains/kotlin/resolve/DeclarationsChecker.java
@@ -202,15 +202,12 @@ public class DeclarationsChecker {
             @NotNull ClassifierDescriptor classifierDescriptor,
             @NotNull PsiElement sourceElement
     ) {
-        Multimap<TypeConstructor, TypeProjection> multimap =
+        Multimap<TypeParameterDescriptor, TypeProjection> multimap =
                 SubstitutionUtils.buildDeepSubstitutionMultimap(classifierDescriptor.getDefaultType());
-        for (Map.Entry<TypeConstructor, Collection<TypeProjection>> entry : multimap.asMap().entrySet()) {
+        for (Map.Entry<TypeParameterDescriptor, Collection<TypeProjection>> entry : multimap.asMap().entrySet()) {
             Collection<TypeProjection> projections = entry.getValue();
             if (projections.size() > 1) {
-                TypeConstructor typeConstructor = entry.getKey();
-                DeclarationDescriptor declarationDescriptor = typeConstructor.getDeclarationDescriptor();
-                assert declarationDescriptor instanceof TypeParameterDescriptor : declarationDescriptor;
-                TypeParameterDescriptor typeParameterDescriptor = (TypeParameterDescriptor) declarationDescriptor;
+                TypeParameterDescriptor typeParameterDescriptor = entry.getKey();
 
                 // Immediate arguments of supertypes cannot be projected
                 Set<KotlinType> conflictingTypes = Sets.newLinkedHashSet();
diff --git a/compiler/frontend/src/org/jetbrains/kotlin/types/SubstitutionUtils.java b/compiler/frontend/src/org/jetbrains/kotlin/types/SubstitutionUtils.java
index 63b704f9f64..50ff55c0057 100644
--- a/compiler/frontend/src/org/jetbrains/kotlin/types/SubstitutionUtils.java
+++ b/compiler/frontend/src/org/jetbrains/kotlin/types/SubstitutionUtils.java
@@ -21,8 +21,8 @@ import com.google.common.collect.Maps;
 import com.google.common.collect.Multimap;
 import org.jetbrains.annotations.NotNull;
 import org.jetbrains.annotations.Nullable;
-import org.jetbrains.kotlin.descriptors.TypeParameterDescriptor;
 import org.jetbrains.kotlin.builtins.KotlinBuiltIns;
+import org.jetbrains.kotlin.descriptors.TypeParameterDescriptor;
 
 import java.util.List;
 import java.util.Map;
@@ -57,8 +57,8 @@ public class SubstitutionUtils {
           F declared in MyFooCollection -> out CharSequence
      */
     @NotNull
-    public static Multimap<TypeConstructor, TypeProjection> buildDeepSubstitutionMultimap(@NotNull KotlinType type) {
-        Multimap<TypeConstructor, TypeProjection> fullSubstitution = LinkedHashMultimap.create();
+    public static Multimap<TypeParameterDescriptor, TypeProjection> buildDeepSubstitutionMultimap(@NotNull KotlinType type) {
+        Multimap<TypeParameterDescriptor, TypeProjection> fullSubstitution = LinkedHashMultimap.create();
         Map<TypeConstructor, TypeProjection> substitution = Maps.newHashMap();
         TypeSubstitutor typeSubstitutor = TypeSubstitutor.create(substitution);
         // we use the mutability of the map here
@@ -71,7 +71,7 @@ public class SubstitutionUtils {
             @NotNull KotlinType context,
             @NotNull TypeSubstitutor substitutor,
             @NotNull Map<TypeConstructor, TypeProjection> substitution,
-            @Nullable Multimap<TypeConstructor, TypeProjection> fullSubstitution
+            @Nullable Multimap<TypeParameterDescriptor, TypeProjection> typeParameterMapping
     ) {
         List<TypeParameterDescriptor> parameters = context.getConstructor().getParameters();
         List<TypeProjection> arguments = context.getArguments();
@@ -87,13 +87,13 @@ public class SubstitutionUtils {
             TypeProjection substitute = substitutor.substitute(argument);
             assert substitute != null;
             substitution.put(parameter.getTypeConstructor(), substitute);
-            if (fullSubstitution != null) {
-                fullSubstitution.put(parameter.getTypeConstructor(), substitute);
+            if (typeParameterMapping != null) {
+                typeParameterMapping.put(parameter, substitute);
             }
         }
         if (KotlinBuiltIns.isNothingOrNullableNothing(context)) return;
         for (KotlinType supertype : context.getConstructor().getSupertypes()) {
-            fillInDeepSubstitutor(supertype, substitutor, substitution, fullSubstitution);
+            fillInDeepSubstitutor(supertype, substitutor, substitution, typeParameterMapping);
         }
     }
 }