public static string ToFormattedName(this MethodReturnType type)
{
// 对 (T, T) 类型的需要特殊考虑。
if (type.ReturnType.FullName.StartsWith("System.ValueTuple`", StringComparison.InvariantCulture) &&
type.ReturnType is GenericInstanceType vgt)
{
var names = type.CustomAttributes.FirstOrDefault(x => x.AttributeType.FullName is "System.Runtime.CompilerServices.TupleElementNamesAttribute")
?.ConstructorArguments.SelectMany(x => (CustomAttributeArgument[])x.Value).Select(x => x.Value as string).ToArray()
?? new string[vgt.GenericArguments.Count];
return($"({string.Join(", ", vgt.GenericArguments.Select((x, i) => $"{x.ToFormattedName()}{(names[i] is null ? "" : $" {names[i]}")}"))})");
}