Can't chain a `std::set` with an `std::vector` about cppitertools HOT 4 CLOSED

A final note, with the c++17 stdlib you will be able to do this with a call to std::as_const

for (auto n : iter::chain(std::as_const(c1), c2))

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This limitation is described in the static_assert and in the README

static assertion failed: All chained iterables must have iterators that dereference to the same type, including cv-qualifiers and references.

Since std::set iterators provide const references, and std::vector's do not, there is a mismatch between the two.

Your example can be made to work by getting a const reference to c1 either by static_casting

for (auto n : iter::chain(static_cast<const std::vector<const char*>&>(c1), c2))

or creating an intermediate const reference to c1

const auto& c1_ref = c1;
for (auto n : iter::chain(c1_ref, c2))

anything that makes the vector iterator dereference to a const reference

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Thanks for the comment. I thought it was related to the caveat, but knew too little to know exactly what it meant. With the work-around you supplied, it indeed works

from cppitertools.

from cppitertools.