improper Invalid.asdict behavior when raising an exception for a subnode

[mmerickel]

def MyMappingValidator(node, value):
    raise colander.Invalid(node['foo'], 'value must be less than 50')

schema = colander.SchemaNode(
    colander.Sequence(),
    colander.SchemaNode(
        colander.Mapping(),
        colander.SchemaNode(colander.Integer(), name='foo'),
        validator=MyMappingValidator,
    ),
)

schema.deserialize([{'foo': 100}])

Results in the following traceback:

Traceback (most recent call last):
  File "<console>", line 1, in <module>
  File "/Users/michael/work/scratch/eggs/colander-1.0b1-py2.7.egg/colander/__init__.py", line 1917, in deserialize
    appstruct = self.typ.deserialize(self, cstruct)
  File "/Users/michael/scratch/eggs/colander-1.0b1-py2.7.egg/colander/__init__.py", line 988, in deserialize
    return self._impl(node, cstruct, callback, accept_scalar)
  File "/Users/michael/scratch/eggs/colander-1.0b1-py2.7.egg/colander/__init__.py", line 930, in _impl
    raise error
Invalid: {'0': 'value must be less than 50'}

Whereas if I put the validator on the node itself, the error message path properly indicates {'0.foo': 'value must be less than 50'}. Please ignore the simplicity of the example, the actual use case is for a validator that checks the subnodes based on other subnodes and the error messages do not come out correct right now.