diff --git a/samples/lambdacalc/languages/sample.fooblin/models/editor.mps b/samples/lambdacalc/languages/sample.fooblin/models/editor.mps
index f34cbf12..3c183880 100644
--- a/samples/lambdacalc/languages/sample.fooblin/models/editor.mps
+++ b/samples/lambdacalc/languages/sample.fooblin/models/editor.mps
@@ -799,5 +799,30 @@
       <node concept="l2Vlx" id="1z4HGmnV7Lp" role="2iSdaV" />
     </node>
   </node>
+  <node concept="24kQdi" id="6_p$mL233Yl">
+    <property role="3GE5qa" value="expr" />
+    <ref role="1XX52x" to="8tt8:6_p$mL233Yk" resolve="IfThenElse" />
+    <node concept="3EZMnI" id="6_p$mL233Yn" role="2wV5jI">
+      <node concept="3F0ifn" id="6_p$mL233Yu" role="3EZMnx">
+        <property role="3F0ifm" value="if" />
+      </node>
+      <node concept="3F1sOY" id="6_p$mL233Z9" role="3EZMnx">
+        <ref role="1NtTu8" to="8tt8:6_p$mL233YL" resolve="cond" />
+      </node>
+      <node concept="3F0ifn" id="6_p$mL233Y$" role="3EZMnx">
+        <property role="3F0ifm" value="then" />
+      </node>
+      <node concept="3F1sOY" id="6_p$mL233Zs" role="3EZMnx">
+        <ref role="1NtTu8" to="8tt8:6_p$mL233YR" resolve="pos" />
+      </node>
+      <node concept="3F0ifn" id="6_p$mL233YG" role="3EZMnx">
+        <property role="3F0ifm" value="else" />
+      </node>
+      <node concept="3F1sOY" id="6_p$mL233ZM" role="3EZMnx">
+        <ref role="1NtTu8" to="8tt8:6_p$mL233YU" resolve="neg" />
+      </node>
+      <node concept="l2Vlx" id="6_p$mL233Yq" role="2iSdaV" />
+    </node>
+  </node>
 </model>
 
diff --git a/samples/lambdacalc/languages/sample.fooblin/models/structure.mps b/samples/lambdacalc/languages/sample.fooblin/models/structure.mps
index 85b1e1de..7b235e36 100644
--- a/samples/lambdacalc/languages/sample.fooblin/models/structure.mps
+++ b/samples/lambdacalc/languages/sample.fooblin/models/structure.mps
@@ -322,5 +322,33 @@
     <property role="34LRSv" value="fix" />
     <ref role="1TJDcQ" node="7_8aRkgDGPJ" resolve="Expr" />
   </node>
+  <node concept="1TIwiD" id="6_p$mL233Yk">
+    <property role="EcuMT" value="7591258541060276116" />
+    <property role="3GE5qa" value="expr" />
+    <property role="TrG5h" value="IfThenElse" />
+    <property role="34LRSv" value="if then else" />
+    <ref role="1TJDcQ" node="7_8aRkgDGPJ" resolve="Expr" />
+    <node concept="1TJgyj" id="6_p$mL233YL" role="1TKVEi">
+      <property role="IQ2ns" value="7591258541060276145" />
+      <property role="20lmBu" value="aggregation" />
+      <property role="20kJfa" value="cond" />
+      <property role="20lbJX" value="1" />
+      <ref role="20lvS9" node="7_8aRkgDGPJ" resolve="Expr" />
+    </node>
+    <node concept="1TJgyj" id="6_p$mL233YR" role="1TKVEi">
+      <property role="IQ2ns" value="7591258541060276151" />
+      <property role="20lmBu" value="aggregation" />
+      <property role="20kJfa" value="pos" />
+      <property role="20lbJX" value="1" />
+      <ref role="20lvS9" node="7_8aRkgDGPJ" resolve="Expr" />
+    </node>
+    <node concept="1TJgyj" id="6_p$mL233YU" role="1TKVEi">
+      <property role="IQ2ns" value="7591258541060276154" />
+      <property role="20lmBu" value="aggregation" />
+      <property role="20kJfa" value="neg" />
+      <property role="20lbJX" value="1" />
+      <ref role="20lvS9" node="7_8aRkgDGPJ" resolve="Expr" />
+    </node>
+  </node>
 </model>
 
diff --git a/samples/lambdacalc/languages/sample.fooblin/models/types.mps b/samples/lambdacalc/languages/sample.fooblin/models/types.mps
index 2cc4b49b..75b69a1e 100644
--- a/samples/lambdacalc/languages/sample.fooblin/models/types.mps
+++ b/samples/lambdacalc/languages/sample.fooblin/models/types.mps
@@ -1180,11 +1180,6 @@
         </node>
       </node>
       <node concept="3Aq9E8" id="N6wx6Hp2i_" role="3otmyu">
-        <node concept="3NuqgR" id="N6wx6Hp31S" role="3Nuqhd">
-          <node concept="aZer4" id="N6wx6Hp31T" role="3XD1gS">
-            <property role="TrG5h" value="Q" />
-          </node>
-        </node>
         <node concept="3NuqgR" id="WBEjvSTpvn" role="3Nuqhd">
           <node concept="aZer4" id="WBEjvSTpvo" role="3XD1gS">
             <property role="TrG5h" value="E" />
@@ -1238,6 +1233,184 @@
         </node>
       </node>
     </node>
+    <node concept="AVZhu" id="6_p$mL23fqI" role="3ArX_J">
+      <property role="TrG5h" value="typeOf_IfThenElse" />
+      <node concept="3Aq93q" id="6_p$mL23fzz" role="3orSU4">
+        <property role="3ArMco" value="true" />
+        <node concept="3I6sU6" id="6_p$mL23fz$" role="3Ip0Jz">
+          <node concept="3I6s7M" id="6_p$mL23gmk" role="3I6sU7">
+            <node concept="3XxkQB" id="6_p$mL23gmg" role="3I6s78">
+              <node concept="aYllk" id="6_p$mL23gmh" role="3XxmmS">
+                <node concept="2OqwBi" id="6_p$mL23gWV" role="aYrYs">
+                  <node concept="3A2sRY" id="6_p$mL23gmt" role="2Oq$k0">
+                    <ref role="3A2yKK" node="6_p$mL23fzC" resolve="ite" />
+                  </node>
+                  <node concept="3TrEf2" id="6_p$mL23h9g" role="2OqNvi">
+                    <ref role="3Tt5mk" to="8tt8:6_p$mL233YL" resolve="cond" />
+                  </node>
+                </node>
+              </node>
+              <node concept="a7P8L" id="6_p$mL23gnn" role="3Xxm5W">
+                <ref role="a7OzE" node="6_p$mL23gmD" resolve="C" />
+              </node>
+            </node>
+          </node>
+          <node concept="3I6s7M" id="6_p$mL23gnQ" role="3I6sU7">
+            <node concept="3XxkQB" id="6_p$mL23gnI" role="3I6s78">
+              <node concept="aYllk" id="6_p$mL23gnK" role="3XxmmS">
+                <node concept="2OqwBi" id="6_p$mL23gwl" role="aYrYs">
+                  <node concept="3A2sRY" id="6_p$mL23go4" role="2Oq$k0">
+                    <ref role="3A2yKK" node="6_p$mL23fzC" resolve="ite" />
+                  </node>
+                  <node concept="3TrEf2" id="6_p$mL23h_w" role="2OqNvi">
+                    <ref role="3Tt5mk" to="8tt8:6_p$mL233YR" resolve="pos" />
+                  </node>
+                </node>
+              </node>
+              <node concept="a7P8L" id="6_p$mL23hBJ" role="3Xxm5W">
+                <ref role="a7OzE" node="6_p$mL23gmM" resolve="P" />
+              </node>
+            </node>
+          </node>
+          <node concept="3I6s7M" id="6_p$mL23hCc" role="3I6sU7">
+            <node concept="3XxkQB" id="6_p$mL23hC4" role="3I6s78">
+              <node concept="aYllk" id="6_p$mL23hC6" role="3XxmmS">
+                <node concept="2OqwBi" id="6_p$mL23hKO" role="aYrYs">
+                  <node concept="3A2sRY" id="6_p$mL23hCz" role="2Oq$k0">
+                    <ref role="3A2yKK" node="6_p$mL23fzC" resolve="ite" />
+                  </node>
+                  <node concept="3TrEf2" id="6_p$mL23hZm" role="2OqNvi">
+                    <ref role="3Tt5mk" to="8tt8:6_p$mL233YU" resolve="neg" />
+                  </node>
+                </node>
+              </node>
+              <node concept="a7P8L" id="6_p$mL23i1_" role="3Xxm5W">
+                <ref role="a7OzE" node="6_p$mL23gn7" resolve="N" />
+              </node>
+            </node>
+          </node>
+        </node>
+        <node concept="3NuqgR" id="6_p$mL23gmC" role="3Nuqhd">
+          <node concept="aZer4" id="6_p$mL23gmD" role="3XD1gS">
+            <property role="TrG5h" value="C" />
+          </node>
+          <node concept="aZer4" id="6_p$mL23gmM" role="3XD1gS">
+            <property role="TrG5h" value="P" />
+          </node>
+          <node concept="aZer4" id="6_p$mL23gn7" role="3XD1gS">
+            <property role="TrG5h" value="N" />
+          </node>
+        </node>
+      </node>
+      <node concept="2t___k" id="6_p$mL23fzB" role="20_v8_">
+        <ref role="2t_S0q" to="8tt8:6_p$mL233Yk" resolve="IfThenElse" />
+        <node concept="3A20r5" id="6_p$mL23fzC" role="2t_VXX">
+          <property role="TrG5h" value="ite" />
+        </node>
+      </node>
+      <node concept="3Aq9E8" id="6_p$mL23i1E" role="3otmyu">
+        <node concept="3I6sU6" id="6_p$mL23i1F" role="3Ip0Jz">
+          <node concept="3I6s7M" id="6_p$mL23i2i" role="3I6sU7">
+            <node concept="3A8Hvi" id="6_p$mL23i2c" role="3I6s78">
+              <node concept="a7P8L" id="6_p$mL23i2s" role="3A8wtg">
+                <ref role="a7OzE" node="6_p$mL23gmD" resolve="C" />
+              </node>
+              <node concept="1Q4cc8" id="6_p$mL23i2x" role="3A8w4Q">
+                <ref role="1nfQt" node="4dPZ2m2hTAN" resolve="Bool" />
+              </node>
+            </node>
+          </node>
+          <node concept="3I6s7M" id="6_p$mL23i2O" role="3I6sU7">
+            <node concept="3A8Hvi" id="6_p$mL23i2I" role="3I6s78">
+              <node concept="a7P8L" id="6_p$mL23i32" role="3A8wtg">
+                <ref role="a7OzE" node="6_p$mL23gmM" resolve="P" />
+              </node>
+              <node concept="1Q4cc8" id="6_p$mL23i37" role="3A8w4Q">
+                <ref role="1nfQt" node="4dPZ2m2hTAN" resolve="Bool" />
+              </node>
+            </node>
+          </node>
+          <node concept="3I6s7M" id="6_p$mL23i3u" role="3I6sU7">
+            <node concept="3A8Hvi" id="6_p$mL23i3o" role="3I6s78">
+              <node concept="a7P8L" id="6_p$mL23i3K" role="3A8wtg">
+                <ref role="a7OzE" node="6_p$mL23gn7" resolve="N" />
+              </node>
+              <node concept="1Q4cc8" id="6_p$mL23i3P" role="3A8w4Q">
+                <ref role="1nfQt" node="4dPZ2m2hTAN" resolve="Bool" />
+              </node>
+            </node>
+          </node>
+          <node concept="3I6s7M" id="6_p$mL23mGP" role="3I6sU7">
+            <node concept="B_ONY" id="6_p$mL23mGL" role="3I6s78">
+              <ref role="17QRF" node="492bFERodOY" resolve="Bool" />
+              <node concept="a7P8L" id="6_p$mL23mHb" role="B_OMz">
+                <ref role="a7OzE" node="6_p$mL23mGl" resolve="T" />
+              </node>
+            </node>
+          </node>
+          <node concept="3I6s7M" id="6_p$mL23i1M" role="3I6sU7">
+            <node concept="3XxkQB" id="6_p$mL23i1I" role="3I6s78">
+              <node concept="aYllk" id="6_p$mL23i1J" role="3XxmmS">
+                <node concept="3A2sRY" id="6_p$mL23i1V" role="aYrYs">
+                  <ref role="3A2yKK" node="6_p$mL23fzC" resolve="ite" />
+                </node>
+              </node>
+              <node concept="a7P8L" id="6_p$mL23mHh" role="3Xxm5W">
+                <ref role="a7OzE" node="6_p$mL23mGl" resolve="T" />
+              </node>
+            </node>
+          </node>
+        </node>
+        <node concept="3NuqgR" id="6_p$mL23mGk" role="3Nuqhd">
+          <node concept="aZer4" id="6_p$mL23mGl" role="3XD1gS">
+            <property role="TrG5h" value="T" />
+          </node>
+        </node>
+      </node>
+      <node concept="3Aq9E8" id="6_p$mL23rks" role="3otmyu">
+        <node concept="3I6sU6" id="6_p$mL23rkt" role="3Ip0Jz">
+          <node concept="3IrJb3" id="6_p$mL23rkS" role="3I6sU7">
+            <node concept="3clFbS" id="6_p$mL23rkT" role="3IrJb0">
+              <node concept="3Aqczg" id="6_p$mL23rkU" role="3cqZAp">
+                <node concept="3wWvb2" id="6_p$mL23rkV" role="3Aqpz8">
+                  <node concept="2YIFZM" id="6_p$mL23rkW" role="3wWo3s">
+                    <ref role="37wK5l" node="WBEjvSTnJK" resolve="formatError" />
+                    <ref role="1Pybhc" node="4dPZ2m2jfZE" resolve="Util" />
+                    <node concept="3A9UF8" id="6_p$mL23rkX" role="37wK5m">
+                      <node concept="a7P8L" id="6_p$mL23rxv" role="3A9W3M">
+                        <ref role="a7OzE" node="6_p$mL23rnG" resolve="E" />
+                      </node>
+                    </node>
+                    <node concept="Xl_RD" id="6_p$mL23rkZ" role="37wK5m">
+                      <property role="Xl_RC" value="expected type Bool" />
+                    </node>
+                  </node>
+                </node>
+              </node>
+              <node concept="3Aqczg" id="6_p$mL23rl4" role="3cqZAp">
+                <node concept="3Aqt3T" id="6_p$mL23rl5" role="3Aqpz8">
+                  <ref role="3AqCNq" node="WBEjvSTpuV" resolve="error" />
+                  <node concept="a7P8L" id="6_p$mL23rJF" role="3AunhB">
+                    <ref role="a7OzE" node="6_p$mL23rnG" resolve="E" />
+                  </node>
+                  <node concept="aYllk" id="6_p$mL23rl7" role="3AunhB">
+                    <node concept="3A2sRY" id="6_p$mL23rOm" role="aYrYs">
+                      <ref role="3A2yKK" node="6_p$mL23fzC" resolve="ite" />
+                    </node>
+                  </node>
+                </node>
+              </node>
+            </node>
+          </node>
+        </node>
+        <node concept="3NuqgR" id="6_p$mL23rnF" role="3Nuqhd">
+          <node concept="aZer4" id="6_p$mL23rnG" role="3XD1gS">
+            <property role="TrG5h" value="E" />
+          </node>
+          <node concept="17QB3L" id="6_p$mL23rxm" role="3vLBG7" />
+        </node>
+      </node>
+    </node>
     <node concept="AVZhu" id="1YCbHn1AJsC" role="3ArX_J">
       <property role="TrG5h" value="typeOf_Fix" />
       <node concept="2t___k" id="1YCbHn1AJ$O" role="20_v8_">
diff --git a/samples/lambdacalc/solutions/sample.demo/models/sample/demo/fooblah.mps b/samples/lambdacalc/solutions/sample.demo/models/sample/demo/fooblah.mps
index 65db2bc1..50f04c1d 100644
--- a/samples/lambdacalc/solutions/sample.demo/models/sample/demo/fooblah.mps
+++ b/samples/lambdacalc/solutions/sample.demo/models/sample/demo/fooblah.mps
@@ -16,6 +16,11 @@
       <concept id="8747055848970356251" name="sample.fooblin.structure.VarRef" flags="ng" index="t0$VC">
         <reference id="8747055848970356252" name="def" index="t0$VJ" />
       </concept>
+      <concept id="7591258541060276116" name="sample.fooblin.structure.IfThenElse" flags="ng" index="FlqVS">
+        <child id="7591258541060276154" name="neg" index="FlqVm" />
+        <child id="7591258541060276151" name="pos" index="FlqVr" />
+        <child id="7591258541060276145" name="cond" index="FlqVt" />
+      </concept>
       <concept id="8739282858702982512" name="sample.fooblin.structure.App" flags="ng" index="1DVIo5">
         <child id="8739282858702982513" name="fun" index="1DVIo4" />
         <child id="8739282858702982525" name="arg" index="1DVIo8" />
@@ -43,6 +48,7 @@
         <child id="2654091495521629866" name="binding" index="j9CMd" />
       </concept>
       <concept id="4774429934441545239" name="sample.fooblin.structure.False" flags="ng" index="3P8L2H" />
+      <concept id="4774429934441530831" name="sample.fooblin.structure.True" flags="ng" index="3P8MHP" />
     </language>
   </registry>
   <node concept="1DVIrt" id="7_8aRkgE06U">
@@ -457,6 +463,18 @@
         </node>
       </node>
     </node>
+    <node concept="1DVJbV" id="6_p$mL23mCW" role="1DVIru">
+      <node concept="1DVIrG" id="6_p$mL23mCY" role="j9CMd">
+        <node concept="1DVIoH" id="6_p$mL23mD0" role="1DVIrJ">
+          <property role="TrG5h" value="aaa" />
+        </node>
+        <node concept="FlqVS" id="6_p$mL23mDN" role="1DVIrD">
+          <node concept="3P8MHP" id="6_p$mL23mDZ" role="FlqVt" />
+          <node concept="3P8MHP" id="6_p$mL23mE2" role="FlqVr" />
+          <node concept="3P8L2H" id="6_p$mL23wZ0" role="FlqVm" />
+        </node>
+      </node>
+    </node>
   </node>
   <node concept="1DVIrt" id="7Et5j8uqHKT">
     <property role="TrG5h" value="SKI" />