From @zoffixznet

The warning NativeCall generates when the library version is unspecified needs to be removed, or at the very least a mechanism for silencing it must be provided.

[REASONS]​:
1) The warnings should point out potential problems in programs, not dictate to the programmer some arbitrary "best practice." A warning generated by Nil eq "foo" is there because comparing a non-value with a string makes no sense and there's likely a problem with the program. Telling a programmer to specify an API version for a library the compiler knows nothing about is overreaching​: there's no problem with the program.
2) As far as I can tell, currently it's impossible to specify more than one version; this is likely why there are several Ecosystem modules that chose to emit the warning in any program that uses the modules.

If there're objections with regard to removing the warning, I suggest a value of * can be interpreted as to mean "any version" (that is, as if it weren't specified).

From @zoffixznet

PR that goes with removing the warning entirely​: rakudo/rakudo#691

PR that uses '*' version to mean 'any version'​: rakudo/rakudo#692

From @zoffixznet

The removal option was merged in this commit​: rakudo/rakudo@fb0a135

@zoffixznet - Status changed from 'new' to 'resolved'

From @geekosaur

On Sat, Jan 23, 2016 at 3​:53 AM, Zoffix Znet <perl6-bugs-followup@​perl.org>
wrote​:

1) The warnings should point out potential problems in programs, not
dictate to the programmer some arbitrary "best practice.

That is only an 'arbitrary "best practice"' if having your program work
correctly is completely unimportant.

--
brandon s allbery kf8nh sine nomine associates
allbery.b@​gmail.com ballbery@​sinenomine.net
unix, openafs, kerberos, infrastructure, xmonad http://sinenomine.net

From @zoffixznet

On Sat Jan 23 04​:36​:52 2016, allbery.b@​gmail.com wrote​:

That is only an 'arbitrary "best practice"' if having your program work
correctly is completely unimportant.

Thank you for showing the EXACT problem with this warning. The compiler makes the assumption the program is broken without having the slightest clue about the library I'm using.