Feature request: change clef in the beginning of piece without affecting other staves

[Pavel Roskin]

Hello!

The only thing I could not properly transcribe in Robert Schumann's "Du
bist wie eine Blume" was the key change from treble to bass in the
beginning on the right hand piano staff.

It may be a strange thing to do, but if Schumann wrote it and it was
printed in several editions of the score, it should be possible
for Lilypond to render.

I also saw this request in forum and mailing posts.  They mention two
workarounds - use \partial and hide bars or use \grace with a hidden
note in all staves.

I consider both unacceptable hacks that would affect the MIDI output and
require changes to all staves.  Lilypond input should be readable and
durable, and adding extra notes to all staves looks like an obfuscation
to me.  Hacks tend to break and scare away potential contributors.

I believe Lilypond should be made smart enough to understand this:

\version "2.15.23"
\score {
  <<
    \new Staff <<
      \context Voice = "melody" { \clef treble \clef bass c1 }
    >>
  >>
  \layout {}
}

As it stands now, the treble key is eliminated.  If the user cares to
write "\clef treble \clef bass", why should the user input be ignored
and the first clef eliminated?

At least there should be an option to suppress such annoying
optimization.

-- 
Regards,
Pavel Roskin