Are tuples of tuples allowed?

More data points:

• If we use std::tr1::tuple and explicitly state the type instead of using auto, then Visual C++ 2008 compiles the code without error. Trying to compile that same code with Visual C++ 2010 results in the error you are seeing.

• If we use boost::tuple an explicitly state the type instead of using auto, then Visual C++ 2008 and Visual C++ 2010 both compile the code without error.

It looks like it is probably an implementation bug.

You've making a tuple with only one member --- doesn't that defeat the purpose of tuples? Anyway, I suspect that's leading to ambiguity.

make_tuple combines type inference with a call to the tuple constructor. When the tuple constructor is called with a single argument which is also a tuple, it's possible that a converting constructor is a better fit than a wrapping constructor. Hence the problem.

Tuples of tuples are allowed. 1-Tuples might not be.