Math digits are in CM with newtxmath and fontspec (LuaLaTeX, TeX Live 2017)

Question

This issue is not new on this site, but I’ve tried earlier solutions and neither works for me. Related questions:

• Math digits are rendered in CM when using libertine and newtxmath with XeLaTeX in TeX Live 2016
• Caveats of newtxmath and fontspec together

My goal is to use newtxmath together with setting system OpenType fonts through fontspec. No matter in which order I load the package, the digits in math mode are rendered in Computer Modern, not Times.

% !TEX program = lualatex

\documentclass[12pt,a4paper]{article}

\usepackage{newtxmath}

\usepackage[no-math]{fontspec}

\setmainfont{Times New Roman}

\begin{document}
Text: 2, Math: \(x=\sqrt{2}\)
\end{document}

Per the newtxmath documentation:

As far as I can tell, newtxmath works with both [XeLaTeX and LuaLaTeX], but requires a very specific loading order and choice of options. [...] the math options must all be loaded prior to loading and using fontspec.

Which I’ve done right in my opinion. My packages are all up-to-date as well.

I’ve tried to adapt this answer for the Times font, but couldn’t make it work.

Answer 1

newtxmath more or less assumes that the default encoding is T1 or OT1. But you can reset the operator font:

\documentclass[12pt,a4paper]{article}

\usepackage{newtxmath}
\DeclareSymbolFont{operators}{OT1}{ntxtlf}{m}{n}
\SetSymbolFont{operators}{bold}{OT1}{ntxtlf}{b}{n}
\usepackage[no-math]{fontspec}

\setmainfont{Times New Roman}

%
\begin{document}
Text: 2, Math: \(x=\sqrt{2}\)

\end{document}

An alternative is to give times the newtx-family name, so that newtxmath can use it.

\documentclass[12pt,a4paper]{article}

\usepackage[no-math]{fontspec}

\setmainfont{Times New Roman}[NFSSFamily=ntxtlf]

\usepackage{newtxmath}

%
\begin{document}
Text: 2, Math: \(x=\sqrt{2}\)

\end{document}

Answer 2

Remove the no-math option and use the trick in my answer to Math digits are rendered in CM when using libertine and newtxmath with XeLaTeX in TeX Live 2016, but augmented for taking care also of other glyphs.

\documentclass[12pt,a4paper]{article}

\usepackage{newtxmath}
\usepackage{fontspec}
\setmainfont{Times New Roman}

\DeclareSymbolFont{oldoperators}{OT1}{ntxtlf}{m}{n}
\SetSymbolFont{oldoperators}{bold}{OT1}{ntxtlf}{b}{n}

\AtBeginDocument{%
  \DeclareMathSymbol{0}{\mathalpha}{operators}{`0}%
  \DeclareMathSymbol{1}{\mathalpha}{operators}{`1}%
  \DeclareMathSymbol{2}{\mathalpha}{operators}{`2}%
  \DeclareMathSymbol{3}{\mathalpha}{operators}{`3}%
  \DeclareMathSymbol{4}{\mathalpha}{operators}{`4}%
  \DeclareMathSymbol{5}{\mathalpha}{operators}{`5}%
  \DeclareMathSymbol{6}{\mathalpha}{operators}{`6}%
  \DeclareMathSymbol{7}{\mathalpha}{operators}{`7}%
  \DeclareMathSymbol{8}{\mathalpha}{operators}{`8}%
  \DeclareMathSymbol{9}{\mathalpha}{operators}{`9}%
  \DeclareMathSymbol{\Gamma}{\mathalpha}{oldoperators}{"00}%
  \DeclareMathSymbol{\Delta}{\mathalpha}{oldoperators}{"01}%
  \DeclareMathSymbol{\Theta}{\mathalpha}{oldoperators}{"02}%
  \DeclareMathSymbol{\Lambda}{\mathalpha}{oldoperators}{"03}%
  \DeclareMathSymbol{\Xi}{\mathalpha}{oldoperators}{"04}%
  \DeclareMathSymbol{\Pi}{\mathalpha}{oldoperators}{"05}%
  \DeclareMathSymbol{\Sigma}{\mathalpha}{oldoperators}{"06}%
  \DeclareMathSymbol{\Upsilon}{\mathalpha}{oldoperators}{"07}%
  \DeclareMathSymbol{\Phi}{\mathalpha}{oldoperators}{"08}%
  \DeclareMathSymbol{\Psi}{\mathalpha}{oldoperators}{"09}%
  \DeclareMathSymbol{\Omega}{\mathalpha}{oldoperators}{"0A}%
  \DeclareMathSymbol{!}{\mathclose}{operators}{"21}%
  \DeclareMathSymbol{+}{\mathbin}{operators}{"2B}%
  \DeclareMathSymbol{:}{\mathrel}{operators}{"3A}%
  \DeclareMathSymbol{;}{\mathpunct}{operators}{"3B}%
  \DeclareMathSymbol{=}{\mathrel}{operators}{"3D}%
  \DeclareMathSymbol{?}{\mathclose}{operators}{"3F}%
  \DeclareMathDelimiter{(}{\mathopen} {operators}{"28}{largesymbols}{"00}%
  \DeclareMathDelimiter{)}{\mathclose}{operators}{"29}{largesymbols}{"01}%
  \DeclareMathDelimiter{[}{\mathopen} {operators}{"5B}{largesymbols}{"02}%
  \DeclareMathDelimiter{]}{\mathclose}{operators}{"5D}{largesymbols}{"03}%
  \DeclareMathAccent{\acute}{\mathalpha}{operators}{"B4}%
  \DeclareMathAccent{\grave}{\mathalpha}{operators}{"60}%
  \DeclareMathAccent{\ddot}{\mathalpha}{operators}{"A8}%
  \DeclareMathAccent{\tilde}{\mathalpha}{oldoperators}{"7E}%
  \DeclareMathAccent{\bar}{\mathalpha}{oldoperators}{"16}%
  \DeclareMathAccent{\breve}{\mathalpha}{oldoperators}{"15}%
  \DeclareMathAccent{\check}{\mathalpha}{oldoperators}{"14}%
  \DeclareMathAccent{\hat}{\mathalpha}{oldoperators}{"5E}%
  \DeclareMathAccent{\dot}{\mathalpha}{oldoperators}{"5F}%
  \DeclareMathAccent{\mathring}{\mathalpha}{oldoperators}{"17}%
  \DeclareMathSymbol{\mathdollar}{\mathord}{operators}{"24}%
}

\begin{document}

Text: 2, Math: \(x=\sqrt{2}+1234567890\)

!+:;=?()[]

${!}{+}{:}{;}{=}{?}{(}{)}{[}{]}$

\'a\`a\"a\~a\=a\u{a}\v{a}\^a\.a\r{a}

$
\acute{\mathrm{a}}
\grave{\mathrm{a}}
\ddot{\mathrm{a}}
\tilde{\mathrm{a}}
\bar{\mathrm{a}}
\breve{\mathrm{a}}
\check{\mathrm{a}}
\hat{\mathrm{a}}
\dot{\mathrm{a}}
\mathring{\mathrm{a}}
$

$\Gamma\Delta\Theta$

\end{document}

Some accents must be taken from newtx instead of Times New Roman, for technical limitations.