diff --git a/languages/jetbrains.mps.jchr/languageModels/typesystem.mps b/languages/jetbrains.mps.jchr/languageModels/typesystem.mps
index 503d052f..19818744 100644
--- a/languages/jetbrains.mps.jchr/languageModels/typesystem.mps
+++ b/languages/jetbrains.mps.jchr/languageModels/typesystem.mps
@@ -194,8 +194,8 @@
                         <node role="closure" roleId="tp2q.1204796294226" type="tp2c.ClosureLiteral" typeId="tp2c.1199569711397" id="1503029987496367" nodeInfo="nn">
                           <node role="body" roleId="tp2c.1199569916463" type="tpee.StatementList" typeId="tpee.1068580123136" id="1503029987496368" nodeInfo="sn">
                             <node role="statement" roleId="tpee.1068581517665" type="tpee.ExpressionStatement" typeId="tpee.1068580123155" id="1503029987496369" nodeInfo="nn">
-                              <node role="expression" roleId="tpee.1068580123156" type="tpee.DotExpression" typeId="tpee.1197027756228" id="1503029987496370" nodeInfo="nn">
-                                <node role="operand" roleId="tpee.1197027771414" type="tpee.DotExpression" typeId="tpee.1197027756228" id="1503029987496371" nodeInfo="nn">
+                              <node role="expression" roleId="tpee.1068580123156" type="tpee.NPEEqualsExpression" typeId="tpee.1225271283259" id="6270176708469944057" nodeInfo="nn">
+                                <node role="leftExpression" roleId="tpee.1081773367580" type="tpee.DotExpression" typeId="tpee.1197027756228" id="1503029987496371" nodeInfo="nn">
                                   <node role="operand" roleId="tpee.1197027771414" type="tpee.VariableReference" typeId="tpee.1068498886296" id="1503029987496372" nodeInfo="nn">
                                     <link role="variableDeclaration" roleId="tpee.1068581517664" targetNodeId="1503029987496378" resolveInfo="var" />
                                   </node>
@@ -203,15 +203,12 @@
                                     <link role="property" roleId="tp25.1138056395725" targetNodeId="tpck.1169194664001" resolveInfo="name" />
                                   </node>
                                 </node>
-                                <node role="operation" roleId="tpee.1197027833540" type="tpee.InstanceMethodCallOperation" typeId="tpee.1202948039474" id="1503029987496374" nodeInfo="nn">
-                                  <link role="baseMethodDeclaration" roleId="tpee.1068499141037" targetNodeId="e2lb.~String%dequals(java%dlang%dObject)%cboolean" resolveInfo="equals" />
-                                  <node role="actualArgument" roleId="tpee.1068499141038" type="tpee.DotExpression" typeId="tpee.1197027756228" id="1503029987496375" nodeInfo="nn">
-                                    <node role="operand" roleId="tpee.1197027771414" type="tpd4.ApplicableNodeReference" typeId="tpd4.1174650418652" id="1503029987496376" nodeInfo="nn">
-                                      <link role="applicableNode" roleId="tpd4.1174650432090" targetNodeId="7781107279594909842" resolveInfo="lv" />
-                                    </node>
-                                    <node role="operation" roleId="tpee.1197027833540" type="tp25.SPropertyAccess" typeId="tp25.1138056022639" id="1503029987496377" nodeInfo="nn">
-                                      <link role="property" roleId="tp25.1138056395725" targetNodeId="tpck.1169194664001" resolveInfo="name" />
-                                    </node>
+                                <node role="rightExpression" roleId="tpee.1081773367579" type="tpee.DotExpression" typeId="tpee.1197027756228" id="1503029987496375" nodeInfo="nn">
+                                  <node role="operand" roleId="tpee.1197027771414" type="tpd4.ApplicableNodeReference" typeId="tpd4.1174650418652" id="1503029987496376" nodeInfo="nn">
+                                    <link role="applicableNode" roleId="tpd4.1174650432090" targetNodeId="7781107279594909842" resolveInfo="lv" />
+                                  </node>
+                                  <node role="operation" roleId="tpee.1197027833540" type="tp25.SPropertyAccess" typeId="tp25.1138056022639" id="1503029987496377" nodeInfo="nn">
+                                    <link role="property" roleId="tp25.1138056395725" targetNodeId="tpck.1169194664001" resolveInfo="name" />
                                   </node>
                                 </node>
                               </node>
@@ -458,13 +455,16 @@
           <node role="variable" roleId="tp2q.9042586985346099778" type="tp2q.MultiForEachVariable" typeId="tp2q.9042586985346099736" id="1503029984966084" nodeInfo="ng">
             <property name="name" nameId="tpck.1169194664001" value="solverParam" />
           </node>
-          <node role="input" roleId="tp2q.9042586985346099735" type="tpee.DotExpression" typeId="tpee.1197027756228" id="1503029984970362" nodeInfo="nn">
-            <node role="operand" roleId="tpee.1197027771414" type="tpd4.ApplicableNodeReference" typeId="tpd4.1174650418652" id="1503029984970169" nodeInfo="nn">
-              <link role="applicableNode" roleId="tpd4.1174650432090" targetNodeId="1503029982163931" resolveInfo="handlerCreator" />
-            </node>
-            <node role="operation" roleId="tpee.1197027833540" type="tp25.SLinkListAccess" typeId="tp25.1138056282393" id="1503029984972380" nodeInfo="nn">
-              <link role="link" roleId="tp25.1138056546658" targetNodeId="vgt0.1503029984919269" />
+          <node role="input" roleId="tp2q.9042586985346099735" type="tpee.DotExpression" typeId="tpee.1197027756228" id="2079564643612558585" nodeInfo="nn">
+            <node role="operand" roleId="tpee.1197027771414" type="tpee.DotExpression" typeId="tpee.1197027756228" id="1503029984970362" nodeInfo="nn">
+              <node role="operand" roleId="tpee.1197027771414" type="tpd4.ApplicableNodeReference" typeId="tpd4.1174650418652" id="1503029984970169" nodeInfo="nn">
+                <link role="applicableNode" roleId="tpd4.1174650432090" targetNodeId="1503029982163931" resolveInfo="handlerCreator" />
+              </node>
+              <node role="operation" roleId="tpee.1197027833540" type="tp25.SLinkListAccess" typeId="tp25.1138056282393" id="1503029984972380" nodeInfo="nn">
+                <link role="link" roleId="tp25.1138056546658" targetNodeId="vgt0.1503029984919269" />
+              </node>
             </node>
+            <node role="operation" roleId="tpee.1197027833540" type="tp2q.ReverseOperation" typeId="tp2q.1175845471038" id="2079564643612562298" nodeInfo="nn" />
           </node>
         </node>
         <node role="forEach" roleId="tp2q.9042586985346099734" type="tp2q.MultiForEachPair" typeId="tp2q.9042586985346099733" id="1503029984973036" nodeInfo="ng">