Issue 1967 in lilypond: \partombineUp and slurs produce misleading warnings

[lilypond]

Status: Accepted
Owner: ----
Labels: Warning Type-Defect

New issue 1967 by address@hidden: \partombineUp and slurs produce  
misleading warnings
http://code.google.com/p/lilypond/issues/detail?id=1967

\version "2.15.14"
\partcombineUp
  \relative c'' { c2( a ~ a1) }
  \relative a'  { a2( f ~ f1) }

this produces correct picture, but throws:

test.ly:3:20: warning: already have slur
  \relative c'' { c2
                    ( a ~ a1) }
test.ly:4:28: warning: cannot end slur
  \relative a'  { a2( f ~ f1
                            ) }