R devel - Jun 2020 - Change in lapply's missing argument passing

Consider the following expression, in which we pass 'i=', with no value
given for the 'i' argument, to lapply.
    lapply("x", function(i, j) c(i=missing(i),j=missing(j),
i=)
>From R-2.14.0 (2011-10-31) through R-3.4.4 (2018-03-15) this evaluated to
c(i=TRUE, j=FALSE).  From R-3.5.0 (2018-04-23) through R-4.0.0 (2020-04-24)
this evaluated to c(i=FALSE, j=TRUE).

Was this change intentional?

Bill Dunlap
TIBCO Software
wdunlap tibco.com

	[[alternative HTML version deleted]]

Yes, to resolve

https://bugs.r-project.org/bugzilla/show_bug.cgi?id=15199

Best,

luke

On Fri, 26 Jun 2020, William Dunlap via R-devel wrote:
> Consider the following expression, in which we pass 'i=', with no
value
> given for the 'i' argument, to lapply.
>    lapply("x", function(i, j) c(i=missing(i),j=missing(j), i=)
> From R-2.14.0 (2011-10-31) through R-3.4.4 (2018-03-15) this evaluated to
> c(i=TRUE, j=FALSE).  From R-3.5.0 (2018-04-23) through R-4.0.0 (2020-04-24)
> this evaluated to c(i=FALSE, j=TRUE).
>
> Was this change intentional?
>
> Bill Dunlap
> TIBCO Software
> wdunlap tibco.com
>
> 	[[alternative HTML version deleted]]
>
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>
-- 
Luke Tierney
Ralph E. Wareham Professor of Mathematical Sciences
University of Iowa                  Phone:             319-335-3386
Department of Statistics and        Fax:               319-335-3017
    Actuarial Science
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