Debugging silent exit of threads in Phobos calls

[ketmar]

Russel Winder wrote:

> On Fri, 2018-06-01 at 17:53 +0300, ketmar via Digitalmars-d-learn
> wrote:
>> 
> […]
>> it looks like "// type T is not constructible from A" phobos
>> assertion triggered. that is, std.variant cannot wrap the struct, and 
>> all hell
>> breaks loose.
>
> An instance of FrontendAppeared is created in frontend_manager module
> and sent to the actor defined in control_window module which has:
>
>     import frontend_manager: FrontendAppeared
>
> It seems the symbol FrontendAppeared in control_window is matching the
> FrontendAppeared type of the message sent, and yet the assertion fails.

it may be something with struct copying. variant wants to copy a struct 
into itself, and somehow failed. either there is no room, or something 
prevented it to do that. it is hard to say more without full source code.