Adding quote with a custom context inside throws warning

[Simon Albrecht]

Hello,

when \addQuote is used and the music within creates a custom context, 
this works as intended but outputs a warning:

%%%%%%%%%%%%%%%%%%%
\version "2.25.12"

\layout {
  \context {
    \Voice
    \name VocalVoice
    \alias Voice
  }
}

sop = \new VocalVoice { 1 }
\addQuote "sop" \sop
%%%%%%%%%%%%%%%%%

=>

Starting lilypond 2.25.12 [Untitled]...
Processing `/tmp/frescobaldi-x5k4p__3/tmpinzgj_k6/document.ly'
Parsing...
/tmp/frescobaldi-x5k4p__3/tmpinzgj_k6/document.ly:12:17: warning: cannot 
create context: VocalVoice
\addQuote "sop"
                \sop
Success: compilation successfully completed
Completed successfully in 0.2".

Best regards
Simon