Multiple IL2049 warnings when publishing with NativeAOT and _AggressiveAttributeTrimming

[Sergio0694]

Description

I tried using _AggressiveAttributeTrimming to check the size diffs, and noticed a whole bunch of warnings:

resource ILLink.LinkAttributes.xml in System.Private.CoreLib(377,8): warning IL2049: System.Private.CoreLib: The internal attribute name 'RemoveAttributeInstances' being used in the xml is not supported by ILLink, check the spelling and the supported internal attributes. [C:\Users\sergiopedri\git\ComputeSharp\samples\ComputeSharp.SwapChain.Cli\ComputeSharp.SwapChain.Cli.csproj]

Reproduction Steps

• Checkout to https://github.com/Sergio0694/ComputeSharp/tree/dev/_AggressiveAttributeTrimming-warn
• Build the CLI sample with these steps:

$env:COMPUTESHARP_SWAPCHAIN_CLI_PUBLISH_AOT='true';
dotnet publish samples\ComputeSharp.SwapChain.Cli\ComputeSharp.SwapChain.Cli.csproj -c Release -f net8.0 -r win-x64

Expected behavior

Should build with no warnings.

Actual behavior

When _AggressiveAttributeTrimming is set, you get a whole bunch of warnings.

Configuration

• 8.0.100-preview.7.23364.32

Tagging subscribers to this area: @agocke, @MichalStrehovsky, @jkotas
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Issue Details

---

Description

I tried using _AggressiveAttributeTrimming to check the size diffs, and noticed a whole bunch of warnings:

resource ILLink.LinkAttributes.xml in System.Private.CoreLib(377,8): warning IL2049: System.Private.CoreLib: The internal attribute name 'RemoveAttributeInstances' being used in the xml is not supported by ILLink, check the spelling and the supported internal attributes. [C:\Users\sergiopedri\git\ComputeSharp\samples\ComputeSharp.SwapChain.Cli\ComputeSharp.SwapChain.Cli.csproj]

Reproduction Steps

• Checkout to https://github.com/Sergio0694/ComputeSharp/tree/dev/_AggressiveAttributeTrimming-warn
• Build the CLI sample with these steps:

$env:COMPUTESHARP_SWAPCHAIN_CLI_PUBLISH_AOT='true';
dotnet publish samples\ComputeSharp.SwapChain.Cli\ComputeSharp.SwapChain.Cli.csproj -c Release -f net8.0 -r win-x64

Expected behavior

Should build with no warnings.

Actual behavior

When _AggressiveAttributeTrimming is set, you get a whole bunch of warnings.

Regression?

No response

Known Workarounds

No response

Configuration

• 8.0.100-preview.7.23364.32

Other information

No response

Author:	Sergio0694
Assignees:	-
Labels:	untriaged, area-NativeAOT-coreclr
Milestone:	-

[MichalStrehovsky]

It's generating a warning because an obscure/useless corner case of the attribute trimming XML format is not implemented. Can be fixed by just not generating the warning (it's unlikely the obscure corner case is worth the effort to implement).

Since _AggressiveAttributeTrimming (or the XML format) is not documented, moving this to Future, pending result of #88805.

[rolfbjarne]

This affects NativeAOT when targeting Apple platforms (net8.0-macos/maccatalyst/ios/tvos):

	resource ILLink.LinkAttributes.xml in System.Private.CoreLib(335): warning IL2049: System.Private.CoreLib: The internal attribute name 'RemoveAttributeInstances' being used in the xml is not supported by ILLink, check the spelling and the supported internal attributes.
	resource ILLink.LinkAttributes.xml in System.Private.CoreLib(342): warning IL2049: System.Private.CoreLib: The internal attribute name 'RemoveAttributeInstances' being used in the xml is not supported by ILLink, check the spelling and the supported internal attributes.
	resource ILLink.LinkAttributes.xml in System.Private.CoreLib(349): warning IL2049: System.Private.CoreLib: The internal attribute name 'RemoveAttributeInstances' being used in the xml is not supported by ILLink, check the spelling and the supported internal attributes.
	resource ILLink.LinkAttributes.xml in System.Private.CoreLib(356): warning IL2049: System.Private.CoreLib: The internal attribute name 'RemoveAttributeInstances' being used in the xml is not supported by ILLink, check the spelling and the supported internal attributes.
	resource ILLink.LinkAttributes.xml in System.Private.CoreLib(363): warning IL2049: System.Private.CoreLib: The internal attribute name 'RemoveAttributeInstances' being used in the xml is not supported by ILLink, check the spelling and the supported internal attributes.
	resource ILLink.LinkAttributes.xml in System.Private.CoreLib(370): warning IL2049: System.Private.CoreLib: The internal attribute name 'RemoveAttributeInstances' being used in the xml is not supported by ILLink, check the spelling and the supported internal attributes.

[MichalStrehovsky]

This affects NativeAOT when targeting Apple platforms (net8.0-macos/maccatalyst/ios/tvos):

Does this show up in customer scenarios? (Would we want this for 8.0?)

[ivanpovazan]

This affects NativeAOT when targeting Apple platforms (net8.0-macos/maccatalyst/ios/tvos):

Does this show up in customer scenarios? (Would we want this for 8.0?)

Sorry for the late reply. Yes these show up in template apps, I have posted examples of warnings here:
dotnet/macios#18571 (comment)
We would like to have dotnet new ios app have 0 warnings for .NET8.

PS I see you have already opened a PR for this, thanks!