The builtin {cargo|rail|road|tram}type functions do not work if the corresponding tables are defined by the user

There is a topic on the forum that the cargotype function does not work:
https://www.tt-forums.net/viewtopic.php?t=90428

I did some test and looks like that in functioncall.py the global constant tables are empty if the tables defined by the nml file:
https://github.com/OpenTTD/nml/blob/bbe945ed348dfe19d284908983c8bb55e0d840ad/nml/expression/functioncall.py#L480C1-L485

I put the following commands after line 494:

    generic.print_dbg(6, global_constants.cargo_numbers)
    generic.print_dbg(6, global_constants.railtype_table)

If I define the cargotable and the railtypetable, then that is the output:

      {}
      {}

So looks like the tables are empty.
If I do not define the railtypetable, the second table is not empty:

      {}
      {'RAIL': 0, 'MONO': 1, 'MGLV': 2}

Version

$ nmlc --version
0.7.4

Expected result:
The attached nml file can be compiled

Actual result:
nmlc ERROR: "test.nml", line 16: Parameter for railtype() must be a string literal that is also in your railtype table

Steps to reproduce:

• nmlc test.nml
  Output:
  nmlc ERROR: "test.nml", line 16: Parameter for railtype() must be a string literal that is also in your railtype table

• Edit the test.nml: comment out the railtypetable:
  // railtypetable { RAIL, ELRL, MONO, MGLV }
nmlc test.nml
  Output:
  nmlc ERROR: "test.nml", line 24: Parameter for cargotype() must be a string literal that is also in your cargo table

• Comment out the cargotable and the cargotype_available if statements too:

// cargotable { PASS, MAIL, LVST }
// if (cargotype_available("LVST"))
// {
// 	item(FEAT_CARGOS, cargo_lvst, cargotype("LVST"))
// 	{ 
// 		property { weight: 12.0/16; }
// 	}
// }

nmlc test.nml
Output:
nmlc info: 0 sprites, 0 cached, 0 orphaned, 0 duplicates, 0 newly encoded (native)
nmlc info: Railtype items: 1/64
nmlc info: Concurrent ActionD registers: 1/64 ("test.nml", line 14)

cargo_type_test.zip

Start by reproducing the failure with the attached test.nml from cargo_type_test.zip using nmlc, then inspect functioncall.py around lines 480-494 and the global constant tables. Done means user-defined cargo and railtype tables are available to cargotype() and railtype() so the example compiles successfully.