Why Throwable.message is not a property

[uranuz]

On Wednesday, 17 March 2021 at 17:52:20 UTC, Adam D. Ruppe wrote:
> On Wednesday, 17 March 2021 at 17:46:27 UTC, uranuz wrote:
>> Also because it is not a property in some contexts when I try 
>> to concatenate it with string without parentheses using "~" 
>> operator it fails
>
> Can you post some sample code that demonstrates this?

Seems that a problem with concatenation is because 
Throwable.message has const(char)[] type, but not string. This 
makes some inconvenience ;-)

There is an example:

import std;

void main()
{
     auto exc = new Exception("Test");
     string longMsg = "The: " ~ exc.message; // Adding parentheses 
() after "message" actually doesn't change anything. Error is the 
same
     writeln(longMsg);
}

Compile error:

onlineapp.d(6): Error: cannot implicitly convert expression "The: 
" ~ exc.message() of type char[] to string

I could add cast(string), but it's not something I want to do.

The reason, why I want to use "message" instead of "msg" is that 
I want to add some extra information to exception as separate 
typed fields. But I want it to be displayed when converting 
exception to string. So I shall override "message" and convert 
this extra info to string...