Feedback Thread: DIP 1032--Function pointers and Delegate Parameters...--Community Review Round 1

[Jonathan Marler]

On Friday, 3 April 2020 at 10:31:12 UTC, Mike Parker wrote:
> This is the feedback thread for the first round of Communnity 
> Review of DIP 1032, "Function pointers and Delegate Parameters 
> Inherit Attributes from Function".
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Instead of delegate/function pointer parameters implicitly 
inheriting all the attributes of the containing function, what if 
we made it "opt-in" with a single attribute? i.e.

@safe pure nothrow @nogc
int foo(int delegate() @inherit dg, int function() @inherit fp)
{
     return dg() + fp();
}

Advantages:

1. No code breakage
2. The developer sees @inherit and knows the function/delegate 
pointer it will contain extra attributes inherited from somewhere 
else.
3. You can still support the case where you don't want any 
attributes.  Example cases of this would be if you're not calling 
the pointer yourself, or, maybe the function itself is nothrow 
but it allows the function/delegate pointers to throw and 
catches/handles their exceptions without propogating them.