Bugfix: comparison involving different types

[gonzalobg88@…]

difference_type does not necessary need to be of type int or size_t

There is a pull request with a patch in: URL_OF_BOOST_RANGE_AT_GITHUB/pull/3 (sorry but for some reason links to pull requests are rejected...)

[Marshall Clow]

But I do believe that it has to be a "signed integer type"

See [iterator.requirements.general]/p1; the last sentence:

For every iterator type X for which equality is defined, there is a corresponding signed integer type called the difference type of the iterator.

See also [basic.fundamental]/p2, which says:

There are five standard signed integer types : “signed char”, “short int”, “int”, “long int”, and “long long int”.

[gonzalobg88@…]

But does it say that user-defined signed integer types are not allowed?

This is just debug code (inside a BOOST_ASSERT), and IMO the problem here is relying on implicit conversions.

Why is this debug code comparing a difference_type which is typically std::ptrdiff_t with an int? Doesn't it make sense to construct a difference_type since it is going to be compared with one anyways?