ValidateDatacards.py fails in compiling RooFormulas

[bonanomi]

When datacards include rateParam lines featuring RooFormulaVars such as:

alphaMuon2FJ_2018_SRH  rateParam Muon2FJ_2018_SRH DYJ @0 alphaMuon2FJ_2018_2Lep

the ValidateDatacards.py tool seem not to able to compile the above expression and brakes:

Error in <RooFormula::Compile>:  Bad numerical expression : "@0"

It seems that replacing the formula with "1.0*@0" fixes the compilation.

Edit: It seems that in general, if the RooFormula is expressed as a string, this does not cause compilation issues. So even:

alphaMuon2FJ_2018_SRH  rateParam Muon2FJ_2018_SRH DYJ "@0" alphaMuon2FJ_2018_2Lep

would work.

An example of datacard to reproduce the issue is this HIG-22-005 card.