cannot use local __lambda1 as parameter to non-global template

[aliak]

Can someone help me understand the details around why this fails?

import std;

struct W(T) {
     T value;
     auto hook(handlers...)() {
         return handlers[0](value);
     }
}

template f(handlers...) {
     auto ref f(T)(auto ref T value) {
         return value.hook!handlers;
     }
}

@nogc void main() {
     auto a = W!int(3);
     auto b = a.f!((_) => "yes");
}

If I specifically type the lambda I pass in to f (i.e. (int _) => 
"yes") then it works. Or if I make hook a global template that 
takes a W!T as the first parameter it also works. Is there a work 
around for this?