Unicode in code oddity

[[)roi(]]

The above C++ code looks wierd, but it's valid?, and compiles fine because of a unicode oddity, zero width space.

The above code works because it is written like this.

#include <iostream>

int main()
{
    int abc = 1;
    int ab\u200Bc = 2;
    int a\u200Bbc = 3;

    std::cout << abc << std::endl; // prints 1
    std::cout << ab\u200Bc << std::endl; // prints 2
    std::cout << a\u200Bbc << std::endl; // prints 3

    return 0;
}

 

[[)roi(]]

Unicode recommends normalisation before compilation (UAX31) so this shouldn't be possible if your linter / compiler comply.

Doubt many do.

Xcode, Swift and by extension LLVM, certainly don't. e.g. compiles fine on Swift:

 

[[)roi(]]

can make for some strange code: