Expose the RequiresLocationAttribute

[tannergooding]

This resolves #85910. It is necessary to avoid potential downstream issues with the use of the attribute as a modreq in virtual members and function pointers.

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Issue Details

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This resolves #85910. It is necessary to avoid potential downstream issues with the use of the attribute as a modreq in virtual members and function pointers.

Author:	tannergooding
Assignees:	-
Labels:	area-System.Runtime.CompilerServices, new-api-needs-documentation
Milestone:	-

[tannergooding]

Marked as draft while this waits for final confirmation from @jaredpar, @jjonescz, @stephentoub

[stephentoub]

Nit: could you add a single test to https://github.com/dotnet/runtime/blob/main/src/libraries/System.Runtime/tests/System/Runtime/CompilerServices/AttributesTests.cs ?

[stephentoub]

Given our offline discussion, I think we should add this now. But I'd like for @jaredpar and/or @jjonescz to confirm we don't foresee any reason to change the attribute before C# 12 ships.

[jaredpar]

But I'd like for @jaredpar and/or @jjonescz to confirm we don't foresee any reason to change the attribute before C# 12 ships.

I do not forsee any changes. There is a C# LDM meeting on ref readonly next Wednesday (Aug 9th). That is just a standard post merge follow up meeting to discuss implementation issues. Don't expect any changes but if they were too happen it would be there. After that it, and even at this point, would take something really significant for us to change the attribute.

[jjonescz]

It is necessary to avoid potential downstream issues with the use of the attribute as a modreq in virtual members and function pointers.

Btw, the attribute isn't used as modreq in virtual methods, the existing InAttribute is used there. RequiresLocationAttribute is used only as modopt in function pointers.