public static IParameterSymbol DetermineParameter(
this ArgumentSyntax argument,
ImmutableArray <IParameterSymbol> parameters,
bool allowParams = false,
CancellationToken cancellationToken = default)
{
argument.ThrowOnNull(nameof(argument));
if (!(argument.Parent is BaseArgumentListSyntax argumentList))
{
return(null);
}
// Handle named argument
if (argument.NameColon != null && !argument.NameColon.IsMissing)
{
string name = argument.NameColon.Name.Identifier.ValueText;
return(parameters.FirstOrDefault(p => p.Name == name));
}
// Handle positional argument
int index = argumentList.Arguments.IndexOf(argument);
if (index < 0)
{
return(null);
}
if (index < parameters.Length)
{
return(parameters[index]);
}
if (allowParams)
{
IParameterSymbol lastParameter = parameters.LastOrDefault();
if (lastParameter == null)
{
return(null);
}
if (lastParameter.IsParams)
{
return(lastParameter);
}
}
return(null);
}
