private static @NotNull List<PsiReferenceExpression> getReadBeforeWrite(@NotNull ControlFlow flow, int startOffset) {
    if (startOffset < 0 || startOffset >= flow.getSize()) {
      return Collections.emptyList();
    }
    final ReadBeforeWriteClientVisitor visitor = new ReadBeforeWriteClientVisitor(flow, false);
    depthFirstSearch(flow, visitor);
    return visitor.getResult(startOffset);
  }
private static @NotNull List<PsiReferenceExpression> getReadBeforeWrite(@NotNull ControlFlow flow, int startOffset)