public sealed override bool IsAssignableFrom(TypeInfo typeInfo)
{
RuntimeTypeInfo toTypeInfo = this;
if (typeInfo == null || !typeInfo.IsRuntimeImplemented())
return false; // Desktop compat: If typeInfo is null, or implemented by a different Reflection implementation, return "false."
RuntimeTypeInfo fromTypeInfo = typeInfo.CastToRuntimeTypeInfo();
if (toTypeInfo.Equals(fromTypeInfo))
return true;
RuntimeTypeHandle toTypeHandle = toTypeInfo.InternalTypeHandleIfAvailable;
RuntimeTypeHandle fromTypeHandle = fromTypeInfo.InternalTypeHandleIfAvailable;
bool haveTypeHandles = !(toTypeHandle.IsNull() || fromTypeHandle.IsNull());
if (haveTypeHandles)
{
// If both types have type handles, let MRT handle this. It's not dependent on metadata.
if (ReflectionCoreExecution.ExecutionEnvironment.IsAssignableFrom(toTypeHandle, fromTypeHandle))
return true;
// Runtime IsAssignableFrom does not handle casts from generic type definitions: always returns false. For those, we fall through to the
// managed implementation. For everyone else, return "false".
//
// Runtime IsAssignableFrom does not handle pointer -> UIntPtr cast.
if (!(fromTypeInfo.IsGenericTypeDefinition || fromTypeInfo.IsPointer))
return false;
}
// If we got here, the types are open, or reduced away, or otherwise lacking in type handles. Perform the IsAssignability check in managed code.
return Assignability.IsAssignableFrom(this, typeInfo, ReflectionCoreExecution.ExecutionDomain.FoundationTypes);
}