private static Pair<Set<String>, Set<TextWithImports>> findReferencedVars(
      Set<String> visibleVars, SourcePosition position) {
    final int line = position.getLine();
    if (line < 0) {
      return Pair.create(Collections.<String>emptySet(), Collections.<TextWithImports>emptySet());
    }
    final PsiFile positionFile = position.getFile();
    if (!positionFile.getLanguage().isKindOf(JavaLanguage.INSTANCE)) {
      return Pair.create(visibleVars, Collections.<TextWithImports>emptySet());
    }

    final VirtualFile vFile = positionFile.getVirtualFile();
    final Document doc =
        vFile != null ? FileDocumentManager.getInstance().getDocument(vFile) : null;
    if (doc == null || doc.getLineCount() == 0 || line > (doc.getLineCount() - 1)) {
      return Pair.create(Collections.<String>emptySet(), Collections.<TextWithImports>emptySet());
    }

    final TextRange limit = calculateLimitRange(positionFile, doc, line);

    int startLine = Math.max(limit.getStartOffset(), line - 1);
    startLine = Math.min(startLine, limit.getEndOffset());
    while (startLine > limit.getStartOffset() && shouldSkipLine(positionFile, doc, startLine)) {
      startLine--;
    }
    final int startOffset = doc.getLineStartOffset(startLine);

    int endLine = Math.min(line + 2, limit.getEndOffset());
    while (endLine < limit.getEndOffset() && shouldSkipLine(positionFile, doc, endLine)) {
      endLine++;
    }
    final int endOffset = doc.getLineEndOffset(endLine);

    final TextRange lineRange = new TextRange(startOffset, endOffset);
    if (!lineRange.isEmpty()) {
      final int offset =
          CharArrayUtil.shiftForward(doc.getCharsSequence(), doc.getLineStartOffset(line), " \t");
      PsiElement element = positionFile.findElementAt(offset);
      if (element != null) {
        PsiMethod method = PsiTreeUtil.getNonStrictParentOfType(element, PsiMethod.class);
        if (method != null) {
          element = method;
        } else {
          PsiField field = PsiTreeUtil.getNonStrictParentOfType(element, PsiField.class);
          if (field != null) {
            element = field;
          } else {
            final PsiClassInitializer initializer =
                PsiTreeUtil.getNonStrictParentOfType(element, PsiClassInitializer.class);
            if (initializer != null) {
              element = initializer;
            }
          }
        }

        //noinspection unchecked
        if (element instanceof PsiCompiledElement) {
          return Pair.create(visibleVars, Collections.<TextWithImports>emptySet());
        } else {
          VariablesCollector collector =
              new VariablesCollector(visibleVars, adjustRange(element, lineRange));
          element.accept(collector);
          return Pair.create(collector.getVars(), collector.getExpressions());
        }
      }
    }
    return Pair.create(Collections.<String>emptySet(), Collections.<TextWithImports>emptySet());
  }
  // copied from DebuggerTree
  private void buildVariablesThreadAction(
      DebuggerContextImpl debuggerContext, XValueChildrenList children, XCompositeNode node) {
    try {
      final EvaluationContextImpl evaluationContext = debuggerContext.createEvaluationContext();
      if (evaluationContext == null) {
        return;
      }
      if (!debuggerContext.isEvaluationPossible()) {
        node.setErrorMessage(MessageDescriptor.EVALUATION_NOT_POSSIBLE.getLabel());
        // myChildren.add(myNodeManager.createNode(MessageDescriptor.EVALUATION_NOT_POSSIBLE,
        // evaluationContext));
      }

      final Location location = myDescriptor.getLocation();

      final ObjectReference thisObjectReference = myDescriptor.getThisObject();
      if (thisObjectReference != null) {
        ValueDescriptorImpl thisDescriptor =
            myNodeManager.getThisDescriptor(null, thisObjectReference);
        children.add(JavaValue.create(thisDescriptor, evaluationContext, myNodeManager));
      } else if (location != null) {
        StaticDescriptorImpl staticDecriptor =
            myNodeManager.getStaticDescriptor(myDescriptor, location.declaringType());
        if (staticDecriptor.isExpandable()) {
          children.addTopGroup(
              new JavaStaticGroup(staticDecriptor, evaluationContext, myNodeManager));
        }
      }

      DebugProcessImpl debugProcess = debuggerContext.getDebugProcess();
      if (debugProcess == null) {
        return;
      }

      // add last method return value if any
      final Pair<Method, Value> methodValuePair = debugProcess.getLastExecutedMethod();
      if (methodValuePair != null) {
        ValueDescriptorImpl returnValueDescriptor =
            myNodeManager.getMethodReturnValueDescriptor(
                myDescriptor, methodValuePair.getFirst(), methodValuePair.getSecond());
        children.add(JavaValue.create(returnValueDescriptor, evaluationContext, myNodeManager));
      }
      // add context exceptions
      for (Pair<Breakpoint, Event> pair :
          DebuggerUtilsEx.getEventDescriptors(debuggerContext.getSuspendContext())) {
        final Event debugEvent = pair.getSecond();
        if (debugEvent instanceof ExceptionEvent) {
          final ObjectReference exception = ((ExceptionEvent) debugEvent).exception();
          if (exception != null) {
            final ValueDescriptorImpl exceptionDescriptor =
                myNodeManager.getThrownExceptionObjectDescriptor(myDescriptor, exception);
            children.add(JavaValue.create(exceptionDescriptor, evaluationContext, myNodeManager));
          }
        }
      }

      try {
        buildVariables(
            debuggerContext,
            evaluationContext,
            debugProcess,
            children,
            thisObjectReference,
            location);
        // if (classRenderer.SORT_ASCENDING) {
        //  Collections.sort(myChildren, NodeManagerImpl.getNodeComparator());
        // }
      } catch (EvaluateException e) {
        node.setErrorMessage(e.getMessage());
        // myChildren.add(myNodeManager.createMessageNode(new MessageDescriptor(e.getMessage())));
      }
    } catch (InvalidStackFrameException e) {
      LOG.info(e);
      // myChildren.clear();
      // notifyCancelled();
    } catch (InternalException e) {
      if (e.errorCode() == 35) {
        node.setErrorMessage(DebuggerBundle.message("error.corrupt.debug.info", e.getMessage()));
        // myChildren.add(
        //  myNodeManager.createMessageNode(new
        // MessageDescriptor(DebuggerBundle.message("error.corrupt.debug.info", e.getMessage()))));
      } else {
        throw e;
      }
    }
  }