diff --git a/compiler/frontend/src/org/jetbrains/jet/lang/resolve/calls/inference/ConstraintSystemImpl.java b/compiler/frontend/src/org/jetbrains/jet/lang/resolve/calls/inference/ConstraintSystemImpl.java
index bbf04dcdc91..c3154caf1cc 100644
--- a/compiler/frontend/src/org/jetbrains/jet/lang/resolve/calls/inference/ConstraintSystemImpl.java
+++ b/compiler/frontend/src/org/jetbrains/jet/lang/resolve/calls/inference/ConstraintSystemImpl.java
@@ -337,7 +337,7 @@ public class ConstraintSystemImpl implements ConstraintSystem {
 
     @Override
     public boolean isSuccessful() {
-        return !hasTypeConstructorMismatch() && !hasUnknownParameters() && !hasConflictingConstraints();
+        return !hasContradiction() && !hasUnknownParameters();
     }
 
     @Override