UserAgent: Mozilla/5.0 (Macintosh; Intel Mac OS X 10_13_4) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/66.0.3359.181 YaBrowser/18.6.1.287 (beta) Yowser/2.5 Safari/537.36

Steps to reproduce the problem:
Google's c++ style guide requires noexcept on moves.
At the same time current precommit checks require that complicated move constructors be declared out of line.

When declaring move constructor/assignment noexcept, default and out of line - some compilers will report a bug when the members of your type are not noexcept move constructible/assignable. And others wouldn't.
Example: https://godbolt.org/g/gUVakx

On top of compilers having different requirements, different standard libraries provide different noexcept guaranties.
For example std::set has a noexcept move constructor in libc++ but doesn't have one in MSVC.

A solution could be to write noexcept default move constructors inline. This, as far as I understand, forces the noexcept regardless of the member characteristics.
Example: https://godbolt.org/g/ze5zNy 

However, it might increase the binary size.
This task should answer: is the binary size increase a real problem if we change the out of line declaration rule.

discussion:
https://groups.google.com/a/chromium.org/forum/?utm_medium=email&utm_source=footer#!msg/cxx/ze4WJFg7RvU/USljDy4WBAAJ

What is the expected behavior?

What went wrong?
(nothing)

Did this work before? N/A 

Chrome version: 66.0.3359.181  Channel: n/a
OS Version: OS X 10.13.4
Flash Version: Shockwave Flash 29.0 r0