Config generator doesn't match nullability semantics of built-in Bind

[stephentoub]

The built-in Bind method annotates the object as nullable:

public static void Bind(this IConfiguration configuration, object? instance)

and then explicitly nops if it's null:

if (instance != null)
{
    ...
}

In contrast, the code generated by the generator annotates it as non-nullable and throws an exception if it's null, changing the semantics when using the source generator.

if (obj is null)
{
    throw new ArgumentNullException(nameof(obj));
}

(It also names the parameter obj instead of instance.)

Tagging subscribers to this area: @dotnet/area-extensions-configuration
See info in area-owners.md if you want to be subscribed.

Issue Details

---

The built-in Bind method annotates the object as nullable:

public static void Bind(this IConfiguration configuration, object? instance)

and then explicitly nops if it's null:

if (instance != null)
{
    ...
}

In contrast, the code generated by the generator annotates it as non-nullable and throws an exception if it's null, changing the semantics when using the source generator.

if (obj is null)
{
    throw new ArgumentNullException(nameof(obj));
}

(It also names the parameter obj instead of instance.)

Author:	stephentoub
Assignees:	-
Labels:	untriaged, area-Extensions-Configuration
Milestone:	-

[layomia]

Consistency is desired cc @tarekgh.