D's Destructors are What Scott Meyers Warned Us About

[Mike Franklin]

On Friday, 25 May 2018 at 23:47:33 UTC, sarn wrote:

> That std.signals code that Steven filed a bug report for is 
> example of why we can't just fix the behaviour, though.  If we 
> just fixed __dtor/__xdtor, any code that used std.signals would 
> start having ugly bugs at run time.
>
> I think that longer term we'll have to deprecate and remove 
> these functions.

I'm very much interested in doing something about these 
functions.  __xdtor is just one.  There are others at 
https://github.com/dlang/druntime/blob/54ab96e9977e0c6baa7ed9740810058fd4aec6ef/src/object.d#L1212-L1229.  __xtoHash is currently causing problems at https://github.com/dlang/dmd/pull/8222

TypeInfo has become my nemesis.  I've been trying to replace 
runtime hooks that depend on TypeInfo with templates that can get 
their information at compile-time, but I'm running into all sorts 
of problems.  e.g. Did you know array.length can be set in @safe 
nothrow pure code, but it lowers to runtime functions that are 
neither @safe, nothrow, nor pure?

Anyway, I'm getting better at modifying the compiler/runtime 
interface.  If we can come up with a solution to this mess, and I 
can understand it, I might be able to implement it.

Mike