How to use labeled break in static foreach?

[Adam D. Ruppe]

this kind of thing doesn't work super well due to the nature of 
compile time. My suggestion is to put the checks and the 
implementation in separate things.

void foo(T...)() {
     static bool checkHelper() {
         bool passed;
         static foreach(t; T) {
             static if(is(t == whatever)) {
                   passed = false;
             }
         }
         return passed;
     }

     static assert(checkHelper());

     // then foreach to do the rest of it
}


something like that. maybe returning string instead of bool to 
have an error message you print out with the static assert.

i don't love this but it is the simplest way I know.