R devel - Oct 2009 - weird warning in [.data.frame with 2.10

I'm getting the following warnings under 2.10 v50082 but not v49613
>> In addition: Warning messages: 1: In `[.data.frame`(df, -(1:nrow(df)),
, drop = FALSE) : named arguments other than 'drop' are discouraged
5: In `[.data.frame`(object, !omit, , drop = FALSE) :
>>   named arguments other than 'drop' are discouraged
In neither case are there any named arguments, as the messages themselves point
out.

The errors are popping up while running my 'debug' package. They are
associated with another sporadic new warning nearby about "number of
items... replacement length", which is more of a direct worry. This has
never happened before in 'debug'; it makes me think that something more
sinister may be going on in the bowels of R, but I haven't tracked it down
clearly enough to report it.

Mark

-- 
Mark Bravington
CSIRO Mathematical & Information Sciences
Marine Laboratory
Castray Esplanade
Hobart 7001
TAS

ph (+61) 3 6232 5118
fax (+61) 3 6232 5012
mob (+61) 438 315 623

--please do not edit the information below--

Version:
 platform = i386-pc-mingw32
 arch = i386
 os = mingw32
 system = i386, mingw32
 status = beta
 major = 2
 minor = 10.0
 year = 2009
 month = 10
 day = 14
 svn rev = 50082
 language = R
 version.string = R version 2.10.0 beta (2009-10-14 r50082)

Windows XP Professional x64 (build 3790) Service Pack 2

Locale:
LC_COLLATE=English_Australia.1252;LC_CTYPE=English_Australia.1252;LC_MONETARY=English_Australia.1252;LC_NUMERIC=C;LC_TIME=English_Australia.1252

Search Path:
 .GlobalEnv, package:grDevices, package:ad, package:chstuff, package:handy2,
package:tweedie, package:statmod, package:handy, package:debug,
package:mvbutils, mvb.session.info, package:tools, package:tcltk, package:stats,
package:graphics, package:utils, package:methods, Autoloads, package:base