id	summary	reporter	owner	description	type	status	priority	milestone	component	version	resolution	keywords	cc
15726	Not returning the value when using tag()	naoliv	team	"Have this small validation rule:

{{{
#!mapcss
*[foo = bar] {
        throwWarning: tr(""something {0}={1}"", ""{0.key}"", tag(""{0.key}""));
}
}}}

and validate an object with `foo=bar`
We can see a message saying `something foo=null`

Of course the common usage is `{0.value}` instead `tag(""{0.key}"")`, but since `tag(key_name)` description says ''""get the value of the key key_name from the object in question""'', shouldn't we see the same result regardless which one we choose here?

JOSM:
{{{
Relative:URL: ^/trunk
Repository:UUID: 0c6e7542-c601-0410-84e7-c038aed88b3b
Last:Changed Date: 2018-01-02 00:31:23 +0100 (Tue, 02 Jan 2018)
Revision:13271
Build-Date:2018-01-02 02:33:50
URL:http://josm.openstreetmap.de/svn/trunk

Identification: JOSM/1.5 (13271 pt_BR) Linux Debian GNU/Linux unstable (sid)
Memory Usage: 576 MB / 5120 MB (173 MB allocated, but free)
Java version: 9.0.1+11-Debian-1, Oracle Corporation, OpenJDK 64-Bit Server VM
Screen: :0.0 1920x1080
Maximum Screen Size: 1920x1080
Java package: openjdk-9-jre:amd64-9.0.1+11-1
Java ATK Wrapper package: libatk-wrapper-java:all-0.33.3-13
VM arguments: [--illegal-access=warn, --add-modules=java.se.ee, -Dawt.useSystemAAFontSettings=on]
Dataset consistency test: No problems found
}}}"	enhancement	new	normal		Core validator			mapcss