diff --git a/compiler/frontend/src/org/jetbrains/jet/lang/diagnostics/rendering/Renderers.java b/compiler/frontend/src/org/jetbrains/jet/lang/diagnostics/rendering/Renderers.java
index d8271ecb495..140343a8444 100644
--- a/compiler/frontend/src/org/jetbrains/jet/lang/diagnostics/rendering/Renderers.java
+++ b/compiler/frontend/src/org/jetbrains/jet/lang/diagnostics/rendering/Renderers.java
@@ -170,7 +170,7 @@ public class Renderers {
 
     public static TabledDescriptorRenderer renderConflictingSubstitutionsInferenceError(InferenceErrorData inferenceErrorData,
             TabledDescriptorRenderer result) {
-        assert inferenceErrorData.constraintsSystem.hasConflictingParameters();
+        assert inferenceErrorData.constraintsSystem.hasConflictingConstraints();
 
         Collection<CallableDescriptor> substitutedDescriptors = Lists.newArrayList();
         Collection<TypeSubstitutor> substitutors = ConstraintsUtil.getSubstitutorsForConflictingParameters(
diff --git a/compiler/frontend/src/org/jetbrains/jet/lang/resolve/calls/CallResolver.java b/compiler/frontend/src/org/jetbrains/jet/lang/resolve/calls/CallResolver.java
index ee108c32cc4..097aac13dd0 100644
--- a/compiler/frontend/src/org/jetbrains/jet/lang/resolve/calls/CallResolver.java
+++ b/compiler/frontend/src/org/jetbrains/jet/lang/resolve/calls/CallResolver.java
@@ -394,7 +394,7 @@ public class CallResolver {
         if (inferenceErrorData.constraintsSystem.hasTypeConstructorMismatch()) {
             trace.report(TYPE_INFERENCE_TYPE_CONSTRUCTOR_MISMATCH.on(element, inferenceErrorData));
         }
-        else if (inferenceErrorData.constraintsSystem.hasConflictingParameters()) {
+        else if (inferenceErrorData.constraintsSystem.hasConflictingConstraints()) {
             trace.report(TYPE_INFERENCE_CONFLICTING_SUBSTITUTIONS.on(element, inferenceErrorData));
         }
         else {
@@ -760,7 +760,7 @@ public class CallResolver {
 
 
         // Solution
-        if (!constraintsSystem.hasContradiction()) {
+        if (!constraintsSystem.hasTypeConstructorMismatch() && !constraintsSystem.hasConflictingConstraints()) { //no contradiction
             candidateCall.setHasUnknownTypeParameters(true);
             return SUCCESS;
         }
diff --git a/compiler/frontend/src/org/jetbrains/jet/lang/resolve/calls/inference/ConstraintsSystemImpl.java b/compiler/frontend/src/org/jetbrains/jet/lang/resolve/calls/inference/ConstraintsSystemImpl.java
index 84bf447f799..e358050b96b 100644
--- a/compiler/frontend/src/org/jetbrains/jet/lang/resolve/calls/inference/ConstraintsSystemImpl.java
+++ b/compiler/frontend/src/org/jetbrains/jet/lang/resolve/calls/inference/ConstraintsSystemImpl.java
@@ -87,8 +87,8 @@ public class ConstraintsSystemImpl implements ConstraintsSystem {
     }
 
     @Override
-    public void registerTypeVariable(@NotNull TypeParameterDescriptor typeParameterDescriptor, @NotNull Variance positionVariance) {
-        typeParameterConstraints.put(typeParameterDescriptor, new TypeConstraintsImpl(positionVariance));
+    public void registerTypeVariable(@NotNull TypeParameterDescriptor typeVariable, @NotNull Variance positionVariance) {
+        typeParameterConstraints.put(typeVariable, new TypeConstraintsImpl(positionVariance));
     }
 
     @NotNull
@@ -198,22 +198,17 @@ public class ConstraintsSystemImpl implements ConstraintsSystem {
 
     @Override
     @Nullable
-    public TypeConstraints getTypeConstraints(@NotNull TypeParameterDescriptor typeParameterDescriptor) {
-        return typeParameterConstraints.get(typeParameterDescriptor);
+    public TypeConstraints getTypeConstraints(@NotNull TypeParameterDescriptor typeVariable) {
+        return typeParameterConstraints.get(typeVariable);
     }
 
     @Override
     public boolean isSuccessful() {
-        return !hasTypeConstructorMismatch() && !hasUnknownParameters() && !hasConflictingParameters();
+        return !hasTypeConstructorMismatch() && !hasUnknownParameters() && !hasConflictingConstraints();
     }
 
     @Override
-    public boolean hasContradiction() {
-        return hasTypeConstructorMismatch() || hasConflictingParameters();
-    }
-
-    @Override
-    public boolean hasConflictingParameters() {
+    public boolean hasConflictingConstraints() {
         for (TypeParameterDescriptor typeParameter : typeParameterConstraints.keySet()) {
             TypeConstraints typeConstraints = getTypeConstraints(typeParameter);
             if (typeConstraints != null && ConstraintsUtil.getValues(typeConstraints).size() > 1) return true;