Ties across voices; tried two methods

[Butter Cream]

Hi ponders, I have a piece of music with alternative ending. The last measure 
prior to the alternative is a single voice has a tied note to both endings. I'v 
e tried two methods but both methods produce similar error: {with no tie} Any 
help would be appreciated.

*.ly:100:42: warning: unterminated tie
    <g d'>4 <g' d'>8 <g c>~ <g c>4 r8 bes
                                         ~ | % m19

[16][16]


I've tried both these methods:
    <g d'>4 <g' d'>8 <g c>~ <g c>4 r8 bes~ | % m19   <-Last measure single voice
  } <- end of repeat Volta 2
  \alternative {
% method one using \new Voice
 { \new Voice = "melody" {
    << { \voiceOne bes8 g4 g8~ g2 }
       \new Voice { \voiceTwo <d f>2 <c e>2 }
    >> \oneVoice
    } | <g d'>4 r r2 | % m
   }
    { { \new Voice = "melody" {
    << { \voiceOne bes'8 g4 g8~ g2 }
       \new Voice { \voiceTwo <d f>2 <c e>2 }
    >> \oneVoice
    } | % m
   } <b d'>4 r r2 | }
  }
  }

\alternative {
% method two using \\
  { << { bes8 g4 g8~ g2 } \\ { <d f>2 <c e>2 } >> | <g d'>4 r r2 | }
  { << { bes8 g4 g8~ g2 } \\ { <d f>2 <c e>2 } >> | <b d'>4 r r2 | }
 }

produces this. with notes not tied.
[cid:e6adac20-74ec-4c19-baf0-ca776f33d2d9]

Thank you.