Data annotations are not being validated on open complex types

[davidmorissette]

Data annotations (validators) are not being validated on objects containing open complex types.

Assemblies affected

OData WebApi 7 Beta 4

Reproduce steps

1- Define an object containing an open complex type and configure it accordingly:

public class PaymentMethod
{
  public string Key { get; set; }
  public IDictionary<string, object> Properties { get; } = new Dictionary<string, object>();
}

2- Define another object and decorate one of its properties with i.e. DataRange:

public class CreditCard
{
  [DataRange(1, 12)]
  public int ExpiryMonth { get; set; }
}

3- POST (or PUT) a JSON body that violates the condition:

{
  "Key": "xyz",
  "Card": {
    "@odata.type": "#Namespace.CreditCard",
        "ExpiryMonth": 13
  }
}

Expected result

Since the provided value (13) violates the DataRange(1, 12) condition, the model state should be invalid.

if (!ModelState.IsValid)
  return BadRequest(ModelState);

Actual result

The model state is valid.

Additional detail

Data annotations (validators) are working as expected on the main object, but not on the open complex type objects.