Delete ForceDictionaryLookups

[jkotas]

No longer used and bit-rotten

[Copilot]

Pull Request Overview

This PR removes the obsolete and unused ForceDictionaryLookupsAttribute to clean up bit-rotten code.

• Deleted the ForceDictionaryLookupsAttribute.cs file.
• Removed the attribute’s references from the project file, ILLink suppression, and compatibility suppressions.
• Eliminated conditional attribute usage in LowLevelList.cs and LowLevelDictionary.cs.

Reviewed Changes

Copilot reviewed 6 out of 6 changed files in this pull request and generated no comments.

Show a summary per file

File	Description
System/Runtime/CompilerServices/ForceDictionaryLookupsAttribute.cs	Deleted obsolete attribute file.
System.Private.CoreLib.csproj	Removed compile inclusion of the deleted attribute.
ILLink.LinkAttributes.xml	Removed suppression entry for the deleted attribute.
CompatibilitySuppressions.xml	Removed suppression reference for the deleted attribute.
LowLevelList.cs	Removed conditional use of the attribute.
LowLevelDictionary.cs	Removed conditional use of the attribute in several locations.

[jkotas]

Context #109114 (comment)

[dotnet-policy-service]

Tagging subscribers to this area: @agocke, @MichalStrehovsky, @jkotas
See info in area-owners.md if you want to be subscribed.

[richlander]

On Linux-x64:

===========================================================================================================
/datadisks/disk1/work/BA0D09AB/w/AAE309D6/e /datadisks/disk1/work/BA0D09AB/w/AAE309D6/e
  Discovering: System.Text.Json.Tests (method display = ClassAndMethod, method display options = None)
  Discovered:  System.Text.Json.Tests (found 8864 of 8931 test cases)
  Starting:    System.Text.Json.Tests (parallel test collections = on [2 threads], stop on fail = off)
ASSERT FAILED
	Expression: !CREATE_CHECK_STRING(bSmallObjectHeapPtr || bLargeObjectHeapPtr)
	Location:   line 562 in /__w/1/s/src/coreclr/vm/object.cpp
	Function:   ValidateInner
	Process:    57177

On Windows:

  Discovering: System.Reflection.Metadata.Tests (method display = ClassAndMethod, method display options = None)
  Discovered:  System.Reflection.Metadata.Tests (found 554 of 558 test cases)
  Starting:    System.Reflection.Metadata.Tests (parallel test collections = on [4 threads], stop on fail = off)
    System.Reflection.Metadata.Decoding.Tests.CustomAttributeDecoderTests.TestCustomAttributeDecoder [SKIP]
      Condition(s) not met: "IsMonoRuntime"
    System.Reflection.Metadata.Tests.Metadata.AssemblyNameInfoTests.CultureNameGetLoweredByToAssemblyName(input: "B-BB", expected: "b-BB") [FAIL]
      Assert.Equal() Failure: Strings differ
                 � (pos 0)
      Expected: "b-BB"
      Actual:   "B-BB"
                 � (pos 0)
      Stack Trace:
        /_/src/libraries/System.Reflection.Metadata/tests/Metadata/AssemblyNameInfoTests.cs(127,0): at System.Reflection.Metadata.Tests.Metadata.AssemblyNameInfoTests.CultureNameGetLoweredByToAssemblyName(String input, String expected)
           at InvokeStub_AssemblyNameInfoTests.CultureNameGetLoweredByToAssemblyName(Object, Span`1)
        /_/src/libraries/System.Private.CoreLib/src/System/Reflection/MethodBaseInvoker.cs(136,0): at System.Reflection.MethodBaseInvoker.InvokeWithFewArgs(Object obj, BindingFlags invokeAttr, Binder binder, Object[] parameters, CultureInfo culture)
  Finished:    System.Reflection.Metadata.Tests

I was just checking to see if the PR I made last week had any more fallout. So just sharing what I found here.

[stephentoub]

On Windows

That one was #117172 which was fixed by #117175.

[jkotas]

On Linux-x64:On Linux-x64:

Unfortunately, the crash dump is corrupted, so it is hard to investigate further. The corrupted dump is likely due to OSError: [Errno 28] No space left on device error.

[jkotas]

/ba-g opened #117186 and dotnet/dnceng#5944. Build analysis is not able to match these issues for unknown reason.