set matastrict within ado files

[Andrea Discacciati]

It's not clear to me why the following program, *saved as an ado file* won't throw an error despite the -mata set matastrict on- (within the ado itself) and the lack of declarations.

program varsum
    version 13
    syntax varname [if] [in]
    marksample touse
    mata: calcsum("`varlist'", "`touse'")
    display as txt " sum = " as res r(sum)
end

version 13
mata:
    mata set matastrict on

    void calcsum(varname, touse)
    {
    st_view(x, ., varname, touse)
    st_numscalar("r(sum)", colsum(x))
    }
end

The program (edited by me: I added the "mata set matastrict on") comes from https://www.stata.com/manuals13/m-1ado.pdf , section "Advice: Use of matastrict".
Am I missing something?

. program dir
  ado      387  varsum
 mata      248  varsum.calcsum()
      --------
           635

[Rafal Raciborski (StataCorp)]

set matastrict on is ignored when the ado-file is automatically loaded. This setting is respected when an ado-file is ran as a do-file, so Andrea can type do varsum.ado and Stata will respond

variable x undeclared
(0 lines skipped)

[Andrea Discacciati]

Dear Rafal, thank you for your kind and swift reply.
I realise now I misinterpreted the text in the user's guide.