Bug? 0 is less than -10

[tcak via Digitalmars-d-learn]

Maybe I am just too stressed out to see the problem.

[code]
import std.stdio;
void main(){
        size_t dec = 0;

	writeln( dec, " ", (dec <= -10), " ", (dec >= 10), " ", ((dec <= 
-10) || (dec >= 10)) );
}
[/code]

[output]
0 true false true
[/output]

How is it generating "true" for (dec <= -10) ? Is there a special 
casting or something?

DMD 2.068.2, Ubuntu 64-bit