LuaLaTex not outputting small caps for Times New Roman

Question

Consider the following MWE:

\documentclass{article}
\usepackage{fontspec}

\setmainfont{Times New Roman}
\begin{document}

\textsc{smallcaps}

\end{document}

When I compile it using XeLaTeX, it produces a document in which the text 'smallcaps' is indeed set in small caps.

However, when I compile it using LuaLaTeX, I receive the error

LaTeX Font Warning: Font shape `TU/TimesNewRoman(0)/m/sc' undefined
(Font)              using `TU/TimesNewRoman(0)/m/n' instead on input line 7.

and the text outputs without small caps.

If I use opentype-info.tex with the font name Times New Roman as in the MWE above, it outputs

script = 'latn'
  ...
    features = ... 'smcp'

which seems to confirm that the font file (which is times.ttf, an OpenType TrueType format font; the version of Times New Roman distributed with the latest update of Word for Mac) does support small caps.

Appending [Letters=SmallCaps] or [RawFeature=+smcp] to \setmainfont{Times New Roman}, as has been suggested elsewhere, has no effect.

How can I use small caps in Times New Roman with LuaLaTeX?

Answer 1

In the time-honoured tradition of discovering the answer to one's question approximately 0.002 seconds after one posts it, it turns out that using \setmainfont{times.ttf} instead of \setmainfont{Times New Roman} produces small caps. In order to load bold, italic, and bold italic fonts as well, something like the following should be used:

\setmainfont{times}[
  Extension      = .ttf ,
  BoldFont       = *bd ,
  ItalicFont     = *i ,
  BoldItalicFont = *bi
]

My suspicion about the cause of my original problem is that although given \setmainfont{Times New Roman} XeLaTeX found the active copy of Times New Roman that came with Word, LuaLaTeX found the inactive copy of Times New Roman that came with macOS, and needed to be pointed in the correct direction using the specific file name. EDIT: As suggested by Ulrike Fischer below, this is confirmed by looking at the log.