setResultsName in version 3.1.1 destroys previous resultnames.

[nilsw1]

I am trying to migrate from version 2.4.5 to 3.1.1 but encounter problems with setResultsName and listAllMatches=True. Is this due to an old error as in #429? That would be unfortunate because I have used this facility extensively. Simplified example:

from pyparsing import  Word, alphas, nums, Optional, delimitedList
import pyparsing
print('pyparsing.version =', pyparsing.__version__)
ident = Word(alphas)
num = Word(nums)
term = (ident('vars*') | num('const*'))('terms*')
func = ident("function_name") + '(' + Optional(delimitedList(term))("args*") + ')'
parsed = func.parseString("fn(a, b, 100)")
print('args =',  parsed.args.asList())
print('terms =', parsed.terms)
print('vars =', parsed.vars)
print('const =', parsed.const)

Gives the following result:

pyparsing.version = 3.1.1
args = [['a', 'b', '100']]
terms = 100
vars = b
const = 100

terms should be the same list as args. In this case I can obviously use args but in more complex cases it could be a subset which is valuable to have.

vars should be the list ['a', 'b'].

In version 2.4.5 I get:

pyparsing245.version = 2.4.5
args = [['a', 'b', '100']]
terms = ['a', 'b', '100']
vars = ['a', 'b']
const = ['100']