Assertion Failed!: MSVCP140D.dll , Expression: ploc->_Mbcurmax == 1 || ploc->_Mbcurmax == 2

[himajin100000]

Hi, himajin100000 here.

Just for explanation(but I'll definitely be very happy if you kindly 
help me.)

I've updated my Visual Studio 2017 Preview to 15.7.0 Preview 6.0 and 
then started to fail to make my own  LibreOffice build with the 
following error.

Debug Assertion Failed!

Program: C:\WINDOWS\SYSTEM32\MSVCP140D.dll
File: f:\dd\vctools\crt\crtw32\stdcpp\xmbtowc.c
Line: 89

Expression: ploc->_Mbcurmax == 1 || ploc->_Mbcurmax == 2
====================FYI========================
Through printf-debugging thingy, I now know

the cause is at
https://opengrok.libreoffice.org/xref/core/unotools/source/i18n/resmgr.cxx?r=01f3d849#126
as the code before this is reached and the code after this is not reached.

FYI:
Translate::Create is called at
https://opengrok.libreoffice.org/xref/core/framework/source/fwe/classes/fwkresid.cxx?r=101a79cc#25

FwkResId is called at
https://opengrok.libreoffice.org/xref/core/framework/source/services/desktop.cxx?r=b4d36b5d#117

probably called by
https://opengrok.libreoffice.org/xref/core/sfx2/source/appl/appinit.cxx?r=c5ab53e3#197

SfxApplication::Initialize_Impl() is called at
https://opengrok.libreoffice.org/xref/core/sfx2/source/appl/app.cxx?r=00ff4d19#147

SfxApplication::GetOrCreate() is called at
https://opengrok.libreoffice.org/xref/core/svx/source/gengal/gengal.cxx?r=b2147abd#277

when gengal.exe is executed.
===================================================
I'm now freezing in front of the daunting task of understanding how to 
use boost library and under what algorithm it works.I'm just at novice 
level even in C++.