Not clear if you want it in text or math...
\documentclass{article}
\usepackage{stackengine}
\begin{document}
In te\stackengine{0pt}{x}{$\rightarrow$}{O}{c}{F}{T}{L}t...
$\ensurestackMath{\stackengine{0pt}{y}{\rightarrow}{O}{c}{F}{T}{L}} = mx + b$
\end{document}

Also, it is not clear if you want the arrow's width to be accounted for:
\documentclass{article}
\usepackage{stackengine}
\begin{document}
In te\stackengine{0pt}{x}{$\rightarrow$}{O}{c}{F}{F}{L}t...
$\ensurestackMath{\stackengine{0pt}{y}{\rightarrow\!}{O}{c}{F}{F}{L}} = mx + b$
\end{document}

Other things that can be easily adjusted above include horizontal alignment (currently centered) as well as vertical height of arrow placement (currently placed at its natural height).
Once the specifics are decided on the use case, this can be easily encapsulated in a macro.
Below, keeping up with the egregs, I implement a macro version (\overarrow
) for math that preserves the math style:
\documentclass{article}
\usepackage{stackengine,scalerel}
\newcommand\overarrow[1]{\ThisStyle{\ensurestackMath{%
\stackengine{0pt}{\SavedStyle#1}{\SavedStyle\rightarrow\!}{O}{c}{F}{F}{L}}}}
\begin{document}
$\overarrow{y} = mx_{\overarrow{z}} + b$
\end{document}

\rlap{$\rightarrow$}x
. Like egreg wrote, you need to figure out which way the excess should go. Note that theadjustbox
package give further ways to lap content to all directions. – Martin Scharrer♦ Feb 19 '19 at 14:45