GCC 7.x issue

[sander-visser]

Bug Report

• What is the issue you have?
  Gcc 7.x complains about json.hpp row ~1581:

    // assertion to check that the iterator range is indeed contiguous,
    // see http://stackoverflow.com/a/35008842/266378 for more discussion
    assert(std::accumulate(
               first, last, std::pair<bool, int>(true, 0),
               [&first](std::pair<bool, int> res, decltype(*first) val)
    {
  

with error "lamda-expression in unevaluated context"

• Please describe the steps to reproduce the issue. Can you provide a small but working code example?
  just include header in hello world application built using gcc 7.3

• What is the expected behavior?

• And what is the actual behavior instead?

• Which compiler and operating system are you using? Is it a supported compiler?

• Did you use a released version of the library or the version from the develop branch?
  looks to be the same on master

• If you experience a compilation error: can you compile and run the unit tests?

Feature Request

• Describe the feature in as much detail as possible.

• Include sample usage where appropriate.

[nlohmann]

We could wrap this line in a #ifndef NDEBUG macro - @sander-visser could you try if this silences the warning?

[theodelrieu]

Is it the same issue as #705?

[sander-visser]

#ifndef wrap allows build to complete. AS i want runtime assertions and since im building using Yocto I guess the proper solution for me would be to cherry pick http://git.yoctoproject.org/cgit.cgi/poky/commit/?id=1bd447bc606603a32a8ff75708bf377bcd82de2d ahead of it being included in yocto rocko. You may close this issue as duplicate/invalid.

[nlohmann]

Duplicate, see #705.