add interface TypeConstraints

containing resulting lower and upper constraints
and being constraintsBuilder's result for each type parameter

compiler/frontend/src/org/jetbrains/jet/lang/resolve/calls/inference/TypeConstraints.java

@@ -0,0 +1,47 @@
+/*
+ * Copyright 2010-2012 JetBrains s.r.o.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ * http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package org.jetbrains.jet.lang.resolve.calls.inference;
+
+import org.jetbrains.annotations.NotNull;
+import org.jetbrains.annotations.Nullable;
+import org.jetbrains.jet.lang.types.JetType;
+import org.jetbrains.jet.lang.types.Variance;
+
+import java.util.Set;
+
+/**
+ * @author svtk
+ */
+public interface TypeConstraints {
+
+    @Nullable
+    JetType getLowerConstraint();
+
+    @Nullable
+    JetType getUpperConstraint();
+
+    @NotNull
+    Set<JetType> getConflicts();
+
+    @NotNull
+    Variance getVariance();
+
+    boolean isSuccessful();
+
+    boolean isEmpty();
+
+}