\version "2.15.30"

\header {
  texidoc = "LilyPond does not support multiple concurrent slurs.  However,
parallel voices can create chords with identical slurs, which shall only
create one slur grob and not print a warning. If the slurs are not
identical, a warning is expected."
}


% Should NOT create a warning, we have identical slurs
\relative c'' {
  c4(( d e f))
}

% Should create a warning, we don't have identical slurs.
#(ly:expect-warning (_ "already have slur"))
% OR: #(ly:expect-warning (_ "cannot end slur"))
\relative c'' {
  c4(( d e) f)
}