Extensible<T> fails on accessing static properties

[BCSharp]

When accessing static properties of T through Extensible<T> (e.g. BigInteger.Zero), a type error is raised. Accessing instance properties (e.g. String.Length) or static fields (e.g. Int32.MaxValue) works fine.

Example:

import clr, System
clr.AddReference('System.Numerics')

bi = System.Numerics.BigInteger(42)
assert bi.IsEven     # OK
assert bi.Zero == 0  # OK

class mybig(System.Numerics.BigInteger): pass

ebi = mybig(42)
assert ebi.IsEven     # OK
assert ebi.Zero == 0  # TypeError: Zero() takes no arguments (0 given)

This issue is blocking #52.

[slozier]

Maybe more of a hack than a proper solution, but I'm thinking the following in ReflectedProperty.CallGetter would do the trick:

Debug.Assert(members.Length == 1);
if (members[0].IsStatic) instance = null;

[BCSharp]

Hmm... Seems that ReflectedProperty.MateGetExpresion may be missing the ExplicitCast expression casting from instance to the declaring type of the chosen getter. I've also noticed that while there are extensive tests in ./Test/interop/net/field and ./Test/interop/net/method, the equivalent tests for properties are missing. So there may be more things that are not quite working for properties. I think it is worth investigating deeper and write the missing tests but for now I'll take your workaround as I want to get the PR for #52 out the door. It will probably take a while to get reviewed, so in the meantime I can tie up some loose ends.