MSVC 2015 Error C2672: no matching overloaded function found

Within the last few days I started getting build errors with MSVC 2015. The last good build was 
about a week ago. Now, I'm getting the following error:


[build CXX] sal/qa/rtl/strings/test_oustring_stringliterals.cxx
[build CXX] sal/qa/rtl/strings/test_strings_toint.cxx
[build CXX] sal/qa/rtl/strings/test_strings_valuex.cxx
[build CXX] sal/qa/rtl/textenc/rtl_tencinfo.cxx
/core/sal/qa/rtl/strings/test_oustring_stringliterals.cxx(265): error C2672: 
'rtlunittest::OUString::equalIgnoreAsciiCase': no matching overloaded function found
/core/sal/qa/rtl/strings/test_oustring_stringliterals.cxx(265): error C2893: Failed to specialize 
function template 'libreoffice_internal::ConstCharArrayDetector<T,bool>::TypeUtf16 
rtlunittest::OUString::equalIgnoreAsciiCase(T &) const'
/core/sal/qa/rtl/strings/test_oustring_stringliterals.cxx(265): note: With the following template 
arguments:
/core/sal/qa/rtl/strings/test_oustring_stringliterals.cxx(265): note: 'T=const char16_t [6]'
/core/sal/qa/rtl/strings/test_oustring_stringliterals.cxx(312): error C2893: Failed to specialize 
function template 
'libreoffice_internal::Enable<rtlunittest::OStringConcat<T1,T2>,rtlunittest::ToStringHelper<T>::allowOStringConcat&&rtlunittest::ToStringHelper<T2>::allowOStringConcat>::Type
 rtlunittest::operator +(const T1 &,const T2 &)'
/core/sal/qa/rtl/strings/test_oustring_stringliterals.cxx(312): note: With the following template 
arguments:
/core/sal/qa/rtl/strings/test_oustring_stringliterals.cxx(312): note: 'T1=rtlunittest::OUString'
/core/sal/qa/rtl/strings/test_oustring_stringliterals.cxx(312): note: 'T2=char16_t [4]'
/core/sal/qa/rtl/strings/test_oustring_stringliterals.cxx(312): error C2784: 
'libreoffice_internal::Enable<rtlunittest::OStringConcat<T,const char 
[N]>,rtlunittest::ToStringHelper<T>::allowOStringConcat>::Type rtlunittest::operator +(const T 
&,const char (&)[N])': could not deduce template argument for 'const char (&)[N]' from 'const 
char16_t [4]'
/core/include\rtl/stringconcat.hxx(231): note: see declaration of 'rtlunittest::operator +'
/core/sal/qa/rtl/strings/test_oustring_stringliterals.cxx(312): error C2784: 
'libreoffice_internal::Enable<rtlunittest::OStringConcat<const char 
[N],T>,rtlunittest::ToStringHelper<T>::allowOStringConcat>::Type rtlunittest::operator +(const char 
(&)[N],const T &)': could not deduce template argument for 'const char (&)[N]' from 
'rtlunittest::OUString'
/core/include\rtl/stringconcat.hxx(239): note: see declaration of 'rtlunittest::operator +'
/core/sal/qa/rtl/strings/test_oustring_stringliterals.cxx(312): error C2784: 
'libreoffice_internal::Enable<rtlunittest::OStringConcat<T,char 
[N]>,rtlunittest::ToStringHelper<T>::allowOStringConcat>::Type rtlunittest::operator +(const T 
&,char (&)[N])': could not deduce template argument for 'char (&)[N]' from 'const char16_t [4]'
/core/include\rtl/stringconcat.hxx(247): note: see declaration of 'rtlunittest::operator +'
/core/sal/qa/rtl/strings/test_oustring_stringliterals.cxx(312): error C2784: 
'libreoffice_internal::Enable<rtlunittest::OStringConcat<char 
[N],T>,rtlunittest::ToStringHelper<T>::allowOStringConcat>::Type rtlunittest::operator +(char 
(&)[N],const T &)': could not deduce template argument for 'char (&)[N]' from 
'rtlunittest::OUString'
/core/include\rtl/stringconcat.hxx(255): note: see declaration of 'rtlunittest::operator +'
/core/sal/qa/rtl/strings/test_oustring_stringliterals.cxx(312): error C2893: Failed to specialize 
function template 
'libreoffice_internal::Enable<rtlunittest::OUStringConcat<T1,T2>,rtlunittest::ToStringHelper<T>::allowOUStringConcat&&rtlunittest::ToStringHelper<T2>::allowOUStringConcat>::Type
 rtlunittest::operator +(const T1 &,const T2 &)'
/core/sal/qa/rtl/strings/test_oustring_stringliterals.cxx(312): note: With the following template 
arguments:
/core/sal/qa/rtl/strings/test_oustring_stringliterals.cxx(312): note: 'T1=rtlunittest::OUString'
/core/sal/qa/rtl/strings/test_oustring_stringliterals.cxx(312): note: 'T2=char16_t [4]'
/core/sal/qa/rtl/strings/test_oustring_stringliterals.cxx(312): error C2893: Failed to specialize 
function template 
'libreoffice_internal::Enable<rtlunittest::OUStringConcat<T1,T2>,rtlunittest::ToStringHelper<T>::allowOUStringConcat&&rtlunittest::ToStringHelper<T2>::allowOUStringConcat&&rtlunittest::libreoffice_internal::ConstCharArrayDetector<T1,void>::ok>::Type
 rtlunittest::operator +(T1 &,const T2 &)'
/core/sal/qa/rtl/strings/test_oustring_stringliterals.cxx(312): note: With the following template 
arguments:
/core/sal/qa/rtl/strings/test_oustring_stringliterals.cxx(312): note: 'T1=rtlunittest::OUString'
/core/sal/qa/rtl/strings/test_oustring_stringliterals.cxx(312): note: 'T2=char16_t [4]'
/core/sal/qa/rtl/strings/test_oustring_stringliterals.cxx(312): error C2893: Failed to specialize 
function template 
'libreoffice_internal::Enable<rtlunittest::OUStringConcat<T1,T2>,rtlunittest::ToStringHelper<T>::allowOUStringConcat&&rtlunittest::ToStringHelper<T2>::allowOUStringConcat&&rtlunittest::libreoffice_internal::ConstCharArrayDetector<T2,void>::ok>::Type
 rtlunittest::operator +(const T1 &,T2 &)'
/core/sal/qa/rtl/strings/test_oustring_stringliterals.cxx(312): note: With the following template 
arguments:
/core/sal/qa/rtl/strings/test_oustring_stringliterals.cxx(312): note: 'T1=rtlunittest::OUString'
/core/sal/qa/rtl/strings/test_oustring_stringliterals.cxx(312): note: 'T2=const char16_t [4]'
/core/sal/qa/rtl/strings/test_oustring_stringliterals.cxx(312): error C2676: binary '+': 
'rtlunittest::OUString' does not define this operator or a conversion to a type acceptable to the 
predefined operator
/core/sal/qa/rtl/strings/test_oustring_stringliterals.cxx(314): error C2893: Failed to specialize 
function template 
'libreoffice_internal::Enable<rtlunittest::OStringConcat<T1,T2>,rtlunittest::ToStringHelper<T>::allowOStringConcat&&rtlunittest::ToStringHelper<T2>::allowOStringConcat>::Type
 rtlunittest::operator +(const T1 &,const T2 &)'
/core/sal/qa/rtl/strings/test_oustring_stringliterals.cxx(314): note: With the following template 
arguments:
/core/sal/qa/rtl/strings/test_oustring_stringliterals.cxx(314): note: 'T1=char16_t [4]'
/core/sal/qa/rtl/strings/test_oustring_stringliterals.cxx(314): note: 'T2=rtlunittest::OUString'
/core/sal/qa/rtl/strings/test_oustring_stringliterals.cxx(314): error C2784: 
'libreoffice_internal::Enable<rtlunittest::OStringConcat<T,const char 
[N]>,rtlunittest::ToStringHelper<T>::allowOStringConcat>::Type rtlunittest::operator +(const T 
&,const char (&)[N])': could not deduce template argument for 'const char (&)[N]' from 
'rtlunittest::OUString'
/core/include\rtl/stringconcat.hxx(231): note: see declaration of 'rtlunittest::operator +'
/core/sal/qa/rtl/strings/test_oustring_stringliterals.cxx(314): error C2784: 
'libreoffice_internal::Enable<rtlunittest::OStringConcat<const char 
[N],T>,rtlunittest::ToStringHelper<T>::allowOStringConcat>::Type rtlunittest::operator +(const char 
(&)[N],const T &)': could not deduce template argument for 'const char (&)[N]' from 'const char16_t 
[4]'
/core/include\rtl/stringconcat.hxx(239): note: see declaration of 'rtlunittest::operator +'
/core/sal/qa/rtl/strings/test_oustring_stringliterals.cxx(314): error C2784: 
'libreoffice_internal::Enable<rtlunittest::OStringConcat<T,char 
[N]>,rtlunittest::ToStringHelper<T>::allowOStringConcat>::Type rtlunittest::operator +(const T 
&,char (&)[N])': could not deduce template argument for 'char (&)[N]' from 'rtlunittest::OUString'
/core/include\rtl/stringconcat.hxx(247): note: see declaration of 'rtlunittest::operator +'
/core/sal/qa/rtl/strings/test_oustring_stringliterals.cxx(314): error C2784: 
'libreoffice_internal::Enable<rtlunittest::OStringConcat<char 
[N],T>,rtlunittest::ToStringHelper<T>::allowOStringConcat>::Type rtlunittest::operator +(char 
(&)[N],const T &)': could not deduce template argument for 'char (&)[N]' from 'const char16_t [4]'
/core/include\rtl/stringconcat.hxx(255): note: see declaration of 'rtlunittest::operator +'
/core/sal/qa/rtl/strings/test_oustring_stringliterals.cxx(314): error C2893: Failed to specialize 
function template 
'libreoffice_internal::Enable<rtlunittest::OUStringConcat<T1,T2>,rtlunittest::ToStringHelper<T>::allowOUStringConcat&&rtlunittest::ToStringHelper<T2>::allowOUStringConcat>::Type
 rtlunittest::operator +(const T1 &,const T2 &)'
/core/sal/qa/rtl/strings/test_oustring_stringliterals.cxx(314): note: With the following template 
arguments:
/core/sal/qa/rtl/strings/test_oustring_stringliterals.cxx(314): note: 'T1=char16_t [4]'
/core/sal/qa/rtl/strings/test_oustring_stringliterals.cxx(314): note: 'T2=rtlunittest::OUString'
/core/sal/qa/rtl/strings/test_oustring_stringliterals.cxx(314): error C2893: Failed to specialize 
function template 
'libreoffice_internal::Enable<rtlunittest::OUStringConcat<T1,T2>,rtlunittest::ToStringHelper<T>::allowOUStringConcat&&rtlunittest::ToStringHelper<T2>::allowOUStringConcat&&rtlunittest::libreoffice_internal::ConstCharArrayDetector<T1,void>::ok>::Type
 rtlunittest::operator +(T1 &,const T2 &)'
/core/sal/qa/rtl/strings/test_oustring_stringliterals.cxx(314): note: With the following template 
arguments:
/core/sal/qa/rtl/strings/test_oustring_stringliterals.cxx(314): note: 'T1=const char16_t [4]'
/core/sal/qa/rtl/strings/test_oustring_stringliterals.cxx(314): note: 'T2=rtlunittest::OUString'
/core/sal/qa/rtl/strings/test_oustring_stringliterals.cxx(314): error C2893: Failed to specialize 
function template 
'libreoffice_internal::Enable<rtlunittest::OUStringConcat<T1,T2>,rtlunittest::ToStringHelper<T>::allowOUStringConcat&&rtlunittest::ToStringHelper<T2>::allowOUStringConcat&&rtlunittest::libreoffice_internal::ConstCharArrayDetector<T2,void>::ok>::Type
 rtlunittest::operator +(const T1 &,T2 &)'
/core/sal/qa/rtl/strings/test_oustring_stringliterals.cxx(314): note: With the following template 
arguments:
/core/sal/qa/rtl/strings/test_oustring_stringliterals.cxx(314): note: 'T1=char16_t [4]'
/core/sal/qa/rtl/strings/test_oustring_stringliterals.cxx(314): note: 'T2=rtlunittest::OUString'
/core/sal/qa/rtl/strings/test_oustring_stringliterals.cxx(314): error C2677: binary '+': no global 
operator found which takes type 'rtlunittest::OUString' (or there is no acceptable conversion)
/core/solenv/gbuild/LinkTarget.mk:189: recipe for target 
'/core/workdir/CxxObject/sal/qa/rtl/strings/test_oustring_stringliterals.o' failed
make[1]: *** [/core/workdir/CxxObject/sal/qa/rtl/strings/test_oustring_stringliterals.o] Error 2
make[1]: *** Waiting for unfinished jobs....
Makefile:264: recipe for target 'build' failed
make: *** [build] Error 2


Stephan, 
Your latest commits are the likely cause. 
https://cgit.freedesktop.org/libreoffice/core/log/sal/qa/rtl/strings/test_oustring_stringliterals.cxx


Could you please look into this?


-