diff --git a/compiler/frontend/src/org/jetbrains/jet/lang/descriptors/FunctionDescriptorImpl.java b/compiler/frontend/src/org/jetbrains/jet/lang/descriptors/FunctionDescriptorImpl.java
index dfe284199d0..810b9907b0c 100644
--- a/compiler/frontend/src/org/jetbrains/jet/lang/descriptors/FunctionDescriptorImpl.java
+++ b/compiler/frontend/src/org/jetbrains/jet/lang/descriptors/FunctionDescriptorImpl.java
@@ -76,8 +76,9 @@ public abstract class FunctionDescriptorImpl extends DeclarationDescriptorImpl i
         for (int i = 0; i < unsubstitutedValueParameters.size(); ++i) {
             // TODO fill me
             int firstValueParameterOffset = 0; // receiver.exists() ? 1 : 0;
-            if (unsubstitutedValueParameters.get(i).getIndex() != i + firstValueParameterOffset) {
-                //throw new IllegalStateException();
+            ValueParameterDescriptor valueParameterDescriptor = unsubstitutedValueParameters.get(i);
+            if (valueParameterDescriptor.getIndex() != i + firstValueParameterOffset) {
+                throw new IllegalStateException(valueParameterDescriptor + "index is " + valueParameterDescriptor.getIndex() + " but position is " + i);
             }
         }
 
diff --git a/compiler/frontend/src/org/jetbrains/jet/lang/types/JetStandardClasses.java b/compiler/frontend/src/org/jetbrains/jet/lang/types/JetStandardClasses.java
index a10d6a3b974..de1a703a87d 100644
--- a/compiler/frontend/src/org/jetbrains/jet/lang/types/JetStandardClasses.java
+++ b/compiler/frontend/src/org/jetbrains/jet/lang/types/JetStandardClasses.java
@@ -395,7 +395,7 @@ public class JetStandardClasses {
         List<ValueParameterDescriptor> valueParameters = Lists.newArrayList();
         for (int i = first; i <= last; i++) {
             JetType parameterType =  arguments.get(i).getType();
-            ValueParameterDescriptorImpl valueParameterDescriptor = new ValueParameterDescriptorImpl(functionDescriptor, i, Collections.<AnnotationDescriptor>emptyList(), "p" + i, false, parameterType, false, null);
+            ValueParameterDescriptorImpl valueParameterDescriptor = new ValueParameterDescriptorImpl(functionDescriptor, i - first, Collections.<AnnotationDescriptor>emptyList(), "p" + i, false, parameterType, false, null);
             valueParameters.add(valueParameterDescriptor);
         }
         return valueParameters;