[Ikvm-developers] Verifier patch for derived interfaces

[Alan M. <Ala...@cr...>]

Hello,

I have isolated a bug in the ikvm verifier and I am attaching a possible
patch.  The problem arises when trying to determine the common base class
for local variable when the local variable is an interface.  The attached
sample code demonstrates the pattern that causes the problem.

Currently, in InstructionState.FindCommonBaseTypeHelper, there are checks
for one interface being the parent of another interface.  But there are no
checks if the two interfaces are both derived from a common interface.  The
attached patch should fix this problem.

Alan

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Alan Macek 
R&D - Crystal Decisions