This bug is similar to bug 17122 ( http://llvm.org/bugs/show_bug.cgi?id=17122 ), except the bug happens in the macro, not in the use of the macro.

Input:

#define STRINGIZE_LITERAL(x) L#x
#define STRINGIZE(x) STRINGIZE_LITERAL(x)

Output:

#define STRINGIZE_LITERAL(x) L #x
#define STRINGIZE(x) STRINGIZE_LITERAL(x)

(Note the space inserted after the L)

Unfortunately I don't know anything about the preprocessor, so I don't know if this STRINGIZE macro is just bogus.

Example:

C:\Users\billy_000\Desktop>type example.cpp
#include <cstdio>

#define HELLO_VERSION 1.0.0
#define STRINGIZE_LITERAL(x) L#x
#define STRINGIZE(x) STRINGIZE_LITERAL(x)

int main()
{
    wchar_t const* message = L"Hello, my version is " STRINGIZE(HELLO_VERSION) L"\n";
    fwprintf(stdout, message);
}


C:\Users\billy_000\Desktop>cl /EHsc /W4 /nologo example.cpp && example.exe
example.cpp
Hello, my version is 1.0.0

C:\Users\billy_000\Desktop>clang++ -o example_clang.exe example.cpp
example.cpp:9:54: error: expected ';' at end of declaration
    wchar_t const* message = L"Hello, my version is " STRINGIZE(HELLO_VERSION) L"\n";
                                                     ^
                                                     ;
1 error generated.

C:\Users\billy_000\Desktop>clang-format -style=LLVM -i example.cpp

C:\Users\billy_000\Desktop>type example.cpp
#include <cstdio>

#define HELLO_VERSION 1.0.0
#define STRINGIZE_LITERAL(x) L #x
#define STRINGIZE(x) STRINGIZE_LITERAL(x)

int main() {
  wchar_t const *message =
      L"Hello, my version is " STRINGIZE(HELLO_VERSION)L"\n";
  fwprintf(stdout, message);
}

C:\Users\billy_000\Desktop>cl /EHsc /W4 /nologo example.cpp && example.exe
example.cpp
example.cpp(9) : error C2146: syntax error : missing ';' before identifier 'L'
example.cpp(9) : error C2065: 'L' : undeclared identifier
example.cpp(9) : error C2143: syntax error : missing ';' before 'string'
example.cpp(9) : error C2308: concatenating mismatched strings
        Concatenating narrow "1.0.0" with wide "
"

C:\Users\billy_000\Desktop>clang++ -o example_clang.exe example.cpp
example.cpp:9:31: error: expected ';' at end of declaration
      L"Hello, my version is " STRINGIZE(HELLO_VERSION)L"\n";
                              ^
                              ;
1 error generated.

Thanks!