Is there a way of causing a compile error if trying to assign a negative number to an unsigned container?

Is there a way of guarding against the resulting binary from the code in t开发者_高级运维his question? Ideally by way of an error at compile time. Example code from the question:

unsigned int nVal = 0;
nVal = -5;  // no error!

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If you are using g++, the switch -Wsign-conversion will warn about the conversion, and -Werror will make that warning an error.

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Edit: Apart from @thiton's answer.

With the simple assignment it's not possible. However, if you assign the value in a little special wrapped way, then it can help. i.e.

nVal = -5;

should be replaced with,

Assign<-5>(nVal);

Where, Assign() looks like,

template<int VAL>
void Assign (unsigned int &nVal)
{
  typedef int arr[(VAL >= 0) 1 : -1];
  nVal = VAL;
}

Demo.