Str concat instead of + ?

Maybe :

bothnumeric :
«Usage of + with numeric value, see manual about usage of sum.»
Not bothnumeric
«Usage of + with string or numeric value, see manual about usage of sum and join.» *

I view this yesterday on a training instance about date. It's clearly string concat needed, but still talk to sum …

Warning text: "Please use concat() instead of '+' when concatenating two strings."

?

Remind : when checking in logic file, you don't have real value …

Then for example : single choice Q1.NAOK return "" even if all choice are number :)

Then bothNumeric : yes sure at 100%, not bothnumeric … : maybe both numeric.

User should type-cast NAOK to int with parseInt().

See the lss : even with
{"Here we must use " + "join"} it show : use sum.

I know user must use sum or join (no need intval …) , and we give him the advice … but seems strabnge to see use sum with {"Here we must use " + "join"}

Then : i think
bothnumeric : use sum
Else : use sum or join

Fix committed to master branch: http://bugs.limesurvey.org/plugin.php?page=Source/view&id=41198