Value Type Exceptions

[IchorDev]

On Sunday, 22 September 2024 at 15:37:04 UTC, Richard (Rikki) 
Andrew Cattermole wrote:
> On 22/09/2024 10:25 PM, IchorDev wrote:
>> But if `caller` is manually marked nothrow then it wouldn’t be 
>> a compiler error anymore just because you didn’t catch 
>> `Exception`?
>
> ``nothrow`` is equivalent to the empty set ``@throw()``, so in 
> the example it is ``nothrow``.
>
> So I'm not sure what you are asking?

In other words, when calling a throwing function, if you catch 
everything in the throw set then can your function be marked 
nothrow? Right now, you have to catch `Exception` to mark your 
function `nothrow`, even if you catch every exception type that 
function can throw individually.

>> Also, could you elaborate on what `:FailedToDecodeUTF` is in 
>> this situation? Like, what exactly is it a member of?
>
> The sumtype that represents the exceptions, specifically a tag 
> that has no payload.
> 
> See my sumtype proposal, this would use that under the hood.

Yes but what would the sum type declaration look like, for 
instance? What is `typeof(:FailedToDecodeUTF)`? The sum type DIP 
mentions something about being able to expand a sum type's 
constraint set; but I didn’t see any examples of it, and this 
would surely be a place where that constraint set expansion is 
utilised, no?