[WASM] browser-wasm tests fail with "Cannot box IsByRefLike type"

[liveans]

Build Information

Build: https://dev.azure.com/dnceng-public/public/_build/results?buildId=695082
Build error leg or test failing: Build browser-wasm linux Release LibraryTests_Threading

Error Message

Fill the error message using step by step known issues guidance.

{
  "ErrorPattern": "System.InvalidProgramException.*Cannot box IsByRefLike type",
  "BuildRetry": false,
  "ExcludeConsoleLog": false
}

Known issue validation

Build: 🔎 https://dev.azure.com/dnceng-public/public/_build/results?buildId=695082
Error message validated: [System.InvalidProgramException.*Cannot box IsByRefLike type]
Result validation: ✅ Known issue matched with the provided build.
Validation performed at: 6/3/2024 6:16:35 PM UTC

Report

Build	Definition	Test	Pull Request
695911	dotnet/runtime	WasmTestOnFirefox-ST-System.Net.Http.Json.Unit.Tests.WorkItemExecution	#101443
696308	dotnet/runtime	WasmTestOnFirefox-ST-System.Net.Http.Json.Unit.Tests.WorkItemExecution	#102845
696281	dotnet/runtime	WasmTestOnFirefox-ST-System.Net.Primitives.Functional.Tests.WorkItemExecution	#103009
696193	dotnet/runtime	WasmTestOnChrome-ST-System.Net.Primitives.Functional.Tests.WorkItemExecution	#103005
695634	dotnet/runtime	WasmTestOnChrome-ST-System.Net.Primitives.Functional.Tests.WorkItemExecution	#102986
696246	dotnet/runtime	WasmTestOnChrome-ST-System.Net.Primitives.Functional.Tests.WorkItemExecution	#103008
696316	dotnet/runtime	WasmTestOnChrome-ST-System.Net.Primitives.Functional.Tests.WorkItemExecution	#102475
696268	dotnet/runtime	WasmTestOnChrome-ST-System.Net.Primitives.Functional.Tests.WorkItemExecution	#102928
696224	dotnet/runtime	WasmTestOnChrome-ST-System.Globalization.Calendars.Hybrid.WASM.Tests.WorkItemExecution
696179	dotnet/runtime	WasmTestOnChrome-ST-System.Net.Http.Json.Unit.Tests.WorkItemExecution	#102295
695848	dotnet/runtime	WasmTestOnChrome-ST-System.Net.Http.Json.Unit.Tests.WorkItemExecution	#102977
696139	dotnet/runtime	WasmTestOnChrome-MT-System.Net.WebSockets.Client.Tests.WorkItemExecution	#101801
695932	dotnet/runtime	WasmTestOnChrome-ST-System.Net.Http.Json.Functional.Tests.WorkItemExecution	#101547
696078	dotnet/runtime	WasmTestOnChrome-ST-System.Net.Mail.Functional.Tests.WorkItemExecution	#102379
696062	dotnet/runtime	WasmTestOnChrome-ST-System.Net.Http.Json.Unit.Tests.WorkItemExecution	#102967
695418	dotnet/runtime	WasmTestOnChrome-ST-System.Formats.Tar.Manual.Tests.WorkItemExecution	#102516
696041	dotnet/runtime	WasmTestOnChrome-ST-System.Diagnostics.Tracing.Tests.WorkItemExecution	#102679
695995	dotnet/runtime	WasmTestOnFirefox-ST-System.Runtime.CompilerServices.Unsafe.Tests.WorkItemExecution	#102998
696017	dotnet/runtime	WasmTestOnChrome-ST-System.Net.Http.Json.Functional.Tests.WorkItemExecution	#102992
695970	dotnet/runtime	WasmTestOnChrome-ST-System.Net.Http.Json.Unit.Tests.WorkItemExecution	#102996
695914	dotnet/runtime	WasmTestOnChrome-ST-System.Net.Http.Json.Unit.Tests.WorkItemExecution	#102994
695900	dotnet/runtime	WasmTestOnChrome-ST-System.Net.Http.Json.Unit.Tests.WorkItemExecution	#102993
695886	dotnet/runtime	WasmTestOnChrome-ST-System.Net.Http.Functional.Tests.WorkItemExecution	#102992
695893	dotnet/runtime	WasmTestOnChrome-ST-System.Net.Http.Json.Unit.Tests.WorkItemExecution	#102967
695882	dotnet/runtime	WasmTestOnFirefox-ST-System.Net.Http.Json.Unit.Tests.WorkItemExecution	#102989
695859	dotnet/runtime	WasmTestOnChrome-ST-System.Net.Http.Json.Unit.Tests.WorkItemExecution	#102991
695799	dotnet/runtime	WasmTestOnChrome-ST-System.Net.Http.Json.Unit.Tests.WorkItemExecution	#102699
695795	dotnet/runtime	WasmTestOnChrome-ST-System.Diagnostics.TextWriterTraceListener.Tests.WorkItemExecution	#102806
695686	dotnet/runtime	WasmTestOnChrome-ST-System.Globalization.Hybrid.WASM.Tests.WorkItemExecution	#102987
695616	dotnet/runtime	WasmTestOnChrome-ST-System.Net.Mail.Functional.Tests.WorkItemExecution	#102597
695594	dotnet/runtime	WasmTestOnChrome-ST-System.Net.Http.Json.Unit.Tests.WorkItemExecution	#102699
695082	dotnet/runtime	WasmTestOnChrome-ST-System.Net.Http.Json.Unit.Tests.WorkItemExecution	#102963

Summary

24-Hour Hit Count	7-Day Hit Count	1-Month Count
0	31	32

[dotnet-policy-service]

Tagging subscribers to 'arch-wasm': @lewing
See info in area-owners.md if you want to be subscribed.

[jkotas]

[07:12:13] fail: System.InvalidProgramException: Cannot box IsByRefLike type 'System.Span`1'
[07:12:13] fail:    at System.Version.TryFormatCore[Char](Span`1 destination, Int32 fieldCount, Int32& charsWritten)
[07:12:13] fail:    at System.Version.System.ISpanFormattable.TryFormat(Span`1 destination, Int32& charsWritten, ReadOnlySpan`1 format, IFormatProvider provider)
[07:12:13] fail:    at System.Text.ValueStringBuilder.AppendFormatHelper(IFormatProvider provider, String format, ReadOnlySpan`1 args)

Introduced by #102795

cc @AaronRobinsonMSFT @stephentoub Looks like Mono is missing byref-like generics support for some patterns.

[stephentoub]

Presumably that particular case is due to the change from MemoryMarshal.Cast<TChar, char>(destination) to Unsafe.BitCast<Span<TChar>, Span<char>>. I can submit a PR to undo those call sites if desirable, though that won't help with the next time one of these is hit. @AaronRobinsonMSFT / @lambdageek, is the long-term fix here for mono quick, or should I revert some of those uses until we can get it sorted out?

[lambdageek]

@stephentoub please revert for now. I'm a bit surprised there's a difference. I think the long term fix for mono is probably quick (most likely BitCast needs to be an intrinsic) but on the order of a week, not a few hours.

[lambdageek]

/cc @steveisok

[lambdageek]

It looks like the problem is this code in Unsafe.Bitcast:

            if (sizeof(TFrom) != sizeof(TTo) || default(TFrom) is null || default(TTo) is null)
            {
                ThrowHelper.ThrowNotSupportedException();
            }
            return ReadUnaligned<TTo>(ref As<TFrom, byte>(ref source));

the test default(TFrom) is null generates:

	IL_000f:  ldloca.s 1
	IL_0011:  initobj !!0
	IL_0017:  ldloc.1 
	IL_0018:  box !!0
	IL_001d:  brfalse.s IL_0035

and I think Mono interpreter doesn't correctly elide the boxing for the box+brfalse pattern.
(Also Unsafe.Bitcast should probably just be an interpreter intrinsic)

[lambdageek]

I have a fix, but for some reason I'm having trouble making a standalone repro. The only way I get it to fail for sure is using our "xunit on chrome" scenario when this line executes:

https://github.com/dotnet/dotnet/blob/98884e3738c664d0950ed42dd9381a27ae630f43/src/source-build-externals/src/xunit/src/xunit.execution/Sdk/Frameworks/XunitTestFrameworkDiscoverer.cs#L21

Doing the same thing in a standalone sample doesn't cause a crash. As far as I can tell it's not due to IL differences. It might be different inlining choices in the interpreter, but I don't see how that would alter what the IL interpreter sees. very strange.

Update Looks like the difference is that our unit tests run with interpreter optimizations disabled, whereas the samples have optimizations.

Update2 Repro is to add this to a browser-wasm sample:

                string s = string.Format(CultureInfo.InvariantCulture, "version is {0}", new object[] {  new Version(1,2,3,4) });

And set these project properties:

  <PropertyGroup>
      <Optimize>false</Optimize>
      <DebuggerSupport>true</DebuggerSupport>
      <WasmDebugLevel>-1</WasmDebugLevel>
      <DebugType>portable</DebugType>
      <EmitDebugInformation>true</EmitDebugInformation>
  </PropertyGroup>