In toc, two chapters appear on the same line when the chapter does not have any section

Question

I have report type document for my thesis. When the chapters do not have sections, the next chapter appears on the same line in toc.

Please let me know what to add more for code:

\documentclass[12pt]{report}

\renewcommand*\contentsname{Table of Contents}

\usepackage{titletoc}% http://ctan.org/pkg/titletoc
\usepackage{enumerate}
\setcounter{secnumdepth}{3}

%%---- continued ----

\titlecontents*{chapter}% <section-type>
[0pt]% <left>
{\addvspace{1em}}% <above-code>
{\bfseries\chaptername\ \thecontentslabel\quad}% <numbered-entry-format>
{}% <numberless-entry-format>
{\bfseries\hfill\contentspage}% <filler-page-format>

\setcounter{secnumdepth}{0}
\input{thesis-statement/statement}
\ifoddchapterpage
\newoddpage
\fi

%%-------------------------------------------------------------------------
\input{introduction/introduction}
\ifoddchapterpage
\newoddpage
\fi

Answer 1

From the titletoc documentation (section 6.2 And more):

This starred version groups the entries in a single paragraph.

So, use \titlecontents, not \titlecontents*:

\documentclass{report}

\usepackage{lipsum}
\usepackage{titletoc}

\titlecontents{chapter}% <section-type>
  [0pt]% <left>
  {\addvspace{1em}}% <above-code>
  {\bfseries\chaptername\ \thecontentslabel\quad}% <numbered-entry-format>
  {}% <numberless-entry-format>
  {\bfseries\hfill\contentspage}% <filler-page-format>

\begin{document}

\tableofcontents

\chapter{Thesis Statement}\lipsum[1-10]

\chapter{Introduction}\lipsum[1-10]
\section{Research approach}\lipsum[11-20]
\section{Research methodology}\lipsum[21-30]
\section{Contributions}\lipsum[31-40]

\chapter{Another chapter}\lipsum[1-10]

\chapter{Final chapter}\lipsum[1-10]

\end{document}