RGF does not work on Arrow Functions or Function expressions

[MichaelXF]

Config and Small code sample

Config:

{
  target: "node",
  rgf: true,
}

Code:

function double1(num){  // Function declaration works
  return num*2;
}

var double2 = function(num){ // Function expression breaks
  return num*2;
}

var double3 = (num)=>{ // Arrow function breaks
  return num*2;
}

console.log(double1(10));
console.log(double2(10));
console.log(double3(10));

Expected behavior

20
20
20

Actual behavior

20
NaN
NaN

[MichaelXF]

Fixed in 1.5.6