Are there any cases where it is incorrect to replace push_back with emplace_back?

Question

Can I break a valid C++03 program by replacing std::vector::push_back with emplace_back and compiling it with C++ 11 compiler? From reading e

Answer 1

Suppose a user-defined class could be initialized from braced-initializer. e.g.

struct S {
    int value;
};

then

std::vector v;

v.push_back({0});    // fine
v.emplace_back({0}); // template type deduction fails

std::vector::emplace_back is template function but std::vector::push_back is non-template function. With a braced-initializer std::vector::emplace_back would fail because template argument deduction fails.

Non-deduced contexts

6) The parameter P, whose A is a braced-init-list, but P is not std::initializer_list or a reference to one:

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