Strage class' with invariant() {} function behaviour

[mumba]

Hello people.

Check this out, and explain please.

class Foo {
    invariant(Object) bar() {
        return new invariant(Object); //return sth caller cannot change
    }
}

So far, so good. Now:

class Foo {
    invariant() {} //some design by contract stuff, nothing related to type's storage classes
    Object bar() { //less restrictive version of the previous func
        return new Object; 
    }
}

So far so good. Now let's make a fusion:

class Foo {
    invariant() {}
    invariant(Object) bar() {
        return new invariant(Object);
    }
}

BANG! (dmd v2.014)
variable test.Foo.bar.__result cannot modify invariant

...

Of course, I have some theories, but I wouldn't come here if they were good, so I'll keep them for myself. Tell me yours.

cheers.