As an example, take any property in core.time - say

    @property long weeks() const pure nothrow { return get!"weeks"(); }

Now make it return auto instead of long. Rebuild druntime, and time.di will have this for weeks:

        auto @property const pure nothrow @property  weeks()
{
return get!("weeks")();
}

Notice that @property is doubled. This will cause compilation errors for Phobos such as

../druntime/import/core/time.di(136): redundant storage class identifier

However, if you change it back to long, you get

        @property const pure nothrow long weeks()
{
return get!("weeks")();
}


So, @property and auto are not getting along when .di files are generated.