From 8b0707b15da72768d6c2785c386cc3516d96f70f Mon Sep 17 00:00:00 2001
From: Svetlana Isakova <svetlana.isakova@jetbrains.com>
Date: Wed, 10 Dec 2014 21:45:13 +0300
Subject: [PATCH] Throw error for conflict in variances to combine

---
 .../src/org/jetbrains/jet/lang/types/TypeSubstitutor.java     | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/core/descriptors/src/org/jetbrains/jet/lang/types/TypeSubstitutor.java b/core/descriptors/src/org/jetbrains/jet/lang/types/TypeSubstitutor.java
index 0238be9e7b4..45376b22f43 100644
--- a/core/descriptors/src/org/jetbrains/jet/lang/types/TypeSubstitutor.java
+++ b/core/descriptors/src/org/jetbrains/jet/lang/types/TypeSubstitutor.java
@@ -286,8 +286,8 @@ public class TypeSubstitutor {
         if (typeParameterVariance == Variance.INVARIANT) return projectionKind;
         if (projectionKind == Variance.INVARIANT) return typeParameterVariance;
         if (typeParameterVariance == projectionKind) return projectionKind;
-        //todo ask why?
-        return Variance.IN_VARIANCE;
+        throw new AssertionError("Variance conflict: type parameter variance '" + typeParameterVariance + "' and " +
+                                 "projection kind '" + projectionKind + "' cannot be combined");
     }
 
     private enum VarianceConflictType {