__aggregate_all_of Internal utility to recursively apply a predicate to aggregate members

[fbusato]

Description

__aggregate_all_of is useful to extract properties for custom traits.

Extract from:

• cuda::is_trivially_copyable #8265

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[fbusato]

@miscco @davebayer @gevtushenko considering the complexity, the impact on compile time, and a couple of compatibility problems with MSVC, I'm not 100% sure it worth to add it.

details:

• compile time: the trait adds an initializer one by one, until it reaches the maximum.
• MSVC doesn't support arrays and nested structures.

[wmaxey]

* MSVC doesn't support arrays and nested structures.

I remember vaguely finding this trick before and decided to write it off based on this. I think we should wait for proper reflection unless this immediately solves problems of our own making internally where we can control what goes through the machinery.

If we can get a guarantee that this will only be used with well supported input types, then I'd consider approving this. Otherwise leaving a footgun laying around concerns me.