Is D's TimSort correct?

[Ali Çehreli via Digitalmars-d]

On 02/24/2015 11:15 AM, ketmar wrote:

 > and it's interesting what complications templates can bring. testing
 > templates is relatively hard now, 'cause programmer must ensure that
 > every path is instantiated (i'm constantly hitting by the bugs in my
 > templates due to missing some codepathes).

I was going to suggest dmd's code coverage tool but I've just witnessed 
the problem first-hand: Uninstantiated template code is not visible to 
the coverage analyser! :-o

Here is the program, where the code inside 'static if' is not covered 
(because argument 'a' is char):

T foo(T)(T v)
{
     static if (T.sizeof == 4) {
         ++v;
     }

     return v;
}

void main()
{
     int a = foo('a');
}

$ dmd deneme.d -cov
$ ./deneme
$ tail --lines=14 deneme.lst
        |T foo(T)(T v)
        |{
        |    static if (T.sizeof == 4) {
        |        ++v;
        |    }
        |
       1|    return v;
        |}
        |
        |void main()
        |{
       1|    int a = foo('a');
        |}
deneme.d is 100% covered

Yay! 100% covered. WAT? :p

Ali