Windows Lilypond 2.18.2 articulate.ly adds an unterminated slur

[Edward McGuire]

<<\include "articulate.ly">> adds an unwanted slur to the printed
score, and causes slur warnings in the log. I can reproduce the
problem using this tiny example. The example does not call for slurs,
but a slur gets added to the printed score.

\version "2.18.2"
\include "english.ly"
\include "articulate.ly"
part = {
        \time 6/8
        \relative d' {
                \set tieWaitForNote = ##t
                \appoggiatura { d8[ ~ a' ~ fs'] ~ } <d, a' fs'>4. r4. |
                \appoggiatura { d8[ ~ a' ~ fs'] ~ } <d, a' fs'>4. r4. |
        }
}
\score {
        \part
}

Here is the log.

Processing `unterminated-slur.ly'
Parsing...
Interpreting music...
warning: cannot end slur
warning: unterminated slur
Preprocessing graphical objects...
Finding the ideal number of pages...
Fitting music on 1 page...
Drawing systems...
Layout output to `unterminated-slur.ps'...
Converting to `./unterminated-slur.pdf'...
Success: compilation successfully completed

If I comment out <<\include "articulate.ly">>, I do not get the slur
or the warnings.

In real world music, I use <<\articulate>> in the score. The error is
reproducible whether or not I use <<\articulate>>.

I looked at existing defects. #5389 "partcombine warns about
unterminated slur" was suspicious, but I'm not calling <<partcombine>>
so I really don't know that it's the same.

Cheers
Edward