Strange error when compiling with dmd, not with ldc

[user1234]

On Wednesday, 29 November 2017 at 10:55:35 UTC, user1234 wrote:
> On Wednesday, 29 November 2017 at 06:18:09 UTC, Fra Mecca wrote:
>> [...]
>
> You must also use a type constructor later, when a 
> Configuration is declared:
>
> ```
> immutable(Configuration) config;
> config.toString.writeln; // okay this time
> ```
>
> What happens is that all the member functions have the 
> `immutable` attribute, but the instance you declared was not 
> itself `immutable`.
>
> actually this:
>
> ```
> immutable struct Configuration {
>     @property string toString(){return "";}
> }
> ```
>
> is like:
>
> ```
> struct Configuration {
>     @property string toString() immutable {return "";}
> }
> ```
>
> I would personally prefer the second form. Why ? Because the 
> variable members will be set immutable anyway when an instance 
> is declared.

And about the DMD vs LDC thing, i thing that the difference can 
be simply explained by the fact that LDC uses a slightly older 
compiler front end version, meaning that after 1 or 2 updates, 
the same error would happen.

Now i don't know which change in particular has been made 
recently in the front-end. Maybe the semantic of the leading 
qualifier when "immutable struct {}" is used but i would bet too 
much on that.