isValidBinaryOp doesn't compile

["Nordlöw"]

In the post

http://forum.dlang.org/thread/bug-6384-3@http.d.puremagic.com/issues/

I tried to compile

template isValidBinaryOp(T1, string op, T2) {
    alias isValidBinaryOp = is(mixin("T1.init" ~ op ~ "T2.init") : 
bool);
}

but it fails as

/home/per/Work/cognia/t_geom.d(80): Error: basic type expected, 
not is
/home/per/Work/cognia/t_geom.d(80): Error: semicolon expected to 
close alias declaration
/home/per/Work/cognia/t_geom.d(80): Error: Declaration expected, 
not 'is'

What is wrong?