Error generating whistler proto when using a globally defined local variable within a named function

[jakeval]

When using a globally-defined local variable from within a named projector, the FieldMapping containing the projector does not list the local variable as an argument. However, when doing the same from an anonymous block, the local variable is listed as an argument.

Example with named projector:
whistle:

var a: "a"

x1: {
   y1: a
}

x2: foo()

def foo() {
    y2: a
}

protobuf:

{
   "root_mapping":{
       "value_source":{
         "const_string":"a"
      },
      "target_local_var":"a"
   },
   "root_mapping":{
      "value_source":{
         "projector":"foo"               <==== the local variable isn't listed as an argument
      },
      "target_field":"x2"
   },
   "projector":{
      "name":"foo",
      "mapping":{
         "value_source":{
            "from_input":{
               "arg":1
            }
         },
         "target_field":"y2"
      }
   },
}

Example with anonymous block:
whistle:

var a: "a"

x1: {
   y1: a
}

protobuf:

{
   "root_mapping":{
      "value_source":{
         "const_string":"a"
      },
      "target_local_var":"a"
   },
   "root_mapping":{
      "value_source":{
         "from_local_var":"a",                <=== the local variable is listed as an argument
         "projector":"$anonblock_3_3"
      },
      "target_field":"x1"
   },
   "projector":{
      "name":"$anonblock_3_3",
      "mapping":{
         "value_source":{
            "from_input":{
               "arg":1
            }
         },
         "target_field":"y1"
      }
   }
}