/// <summary>
/// Returns method as defined on a non-generic base class or on a base
/// instantiation.
/// For example, If Foo<T> : Bar<T> and overrides method M,
/// if method is Bar<string>.M(), then this returns Bar<T>.M()
/// but if Foo : Bar<string>, then this returns Bar<string>.M()
/// </summary>
/// <param name="targetType">A potentially derived type</param>
/// <param name="method">A base class's virtual method</param>
public static MethodDesc FindMethodOnTypeWithMatchingTypicalMethod(this TypeDesc targetType, MethodDesc method)
{
// If method is nongeneric and on a nongeneric type, then it is the matching method
if (!method.HasInstantiation && !method.OwningType.HasInstantiation)
{
return(method);
}
// Since method is an instantiation that may or may not be the same as typeExamine's hierarchy,
// find a matching base class on an open type and then work from the instantiation in typeExamine's
// hierarchy
TypeDesc typicalTypeOfTargetMethod = method.GetTypicalMethodDefinition().OwningType;
TypeDesc targetOrBase = targetType;
do
{
TypeDesc openTargetOrBase = targetOrBase;
if (openTargetOrBase is InstantiatedType)
{
openTargetOrBase = openTargetOrBase.GetTypeDefinition();
}
if (openTargetOrBase == typicalTypeOfTargetMethod)
{
// Found an open match. Now find an equivalent method on the original target typeOrBase
MethodDesc matchingMethod = targetOrBase.FindMethodOnExactTypeWithMatchingTypicalMethod(method);
return(matchingMethod);
}
targetOrBase = targetOrBase.BaseType;
} while (targetOrBase != null);
Debug.Fail("method has no related type in the type hierarchy of type");
return(null);
}