programming error: (de)crescendo on items with specified volume.

[Ed Ravin]

I started getting this message:

  programming error: (de)crescendo on items with specified volume.

When I added this line to the melody portion (of a singer with piano piece)

       \times 2/3 { e8 e e } e,4. \> e8 \! \p ^"rit." ds e |

The warning goes away if I remove the "\p".  I have plenty of similar
syntax elsewhere in the file, like:

       b8 a4. \> ^"rit." r8 f8 \! \mp e f |

This is the same  piece that has the other warning I just posted
about "going back in MIDI time".  In spite of the two warnings both
the PDF and  MIDI output seem OK.