Remove NET9_0_OR_GREATER and NET10_0_OR_GREATER preprocessor constants

[Copilot]

Cleanup of .NET Version Constants

The repo no longer builds for .NET Core versions older than 10. This PR removes obsolete version-specific preprocessor constants (NET9_0_OR_GREATER, NET10_0_OR_GREATER).

Strategy

For files that only build for .NET 10+ runtime (System.Private.CoreLib):

• Replace #if NET9_0_OR_GREATER / #if NET10_0_OR_GREATER with #if NET
• This is needed because these files are also compiled by packages like Microsoft.Bcl.AsyncInterfaces which target netstandard/netframework

For files in netcore directories or ending in netcore.cs:

• These are .NET Core only, so #if NET checks are removed entirely and code is made unconditional
• Fixed formatting where lines were awkwardly split due to removed #if directives

For other files that also build for netstandard/netframework:

• Replaced NET9_0_OR_GREATER / NET10_0_OR_GREATER with just NET
• This maintains the distinction between .NET Core and netstandard/netframework
• Conditions use #if NET ... #else ... #endif structure

For test files:

• Replaced NET9_0_OR_GREATER / NET10_0_OR_GREATER with NET since test projects target both .NET Core and .NET Framework

Files Changed

Source files:

• System.Private.CoreLib Base64 helpers, IAsyncEnumerable/IAsyncEnumerator, ConfiguredCancelableAsyncEnumerable
• Common/src crypto helpers (HexConverter uses #if NET ... #else structure)
• Microsoft.Bcl.Cryptography, Microsoft.Bcl.Memory
• Microsoft.Extensions.Caching, Configuration.Binder, DependencyInjection, Options
• System.Collections.Immutable, Diagnostics.DiagnosticSource, DirectoryServices.Protocols
• System.Formats.Asn1, System.Formats.Nrbf, System.Numerics.Tensors (netcore files updated with clean formatting)
• System.Security.Cryptography.Pkcs/Xml, System.Text.Json, System.Threading.Channels
• Reference assemblies
• Test baseline files for Microsoft.Extensions.Options source generators

Test files:

• Common/tests/System/Security/Cryptography/ByteUtils.cs
• Common/tests/System/Security/Cryptography/X509Certificates/X509CertificateLoaderPkcs12Tests.cs
• Common/tests/System/Security/Cryptography/X509Certificates/X509CertificateLoaderPkcs12CollectionTests.cs
• Microsoft.Extensions.Caching.Memory/tests/AltLookupTests.cs
• System.Formats.Asn1/tests/Writer/*.cs
• System.Text.Json/tests/Common/MetadataTests.cs
• System.Text.Json/tests/System.Text.Json.SourceGeneration.Tests/Serialization/MetadataTests.cs
• System.Text.Json/tests/System.Text.Json.SourceGeneration.Unit.Tests/JsonSourceGeneratorDiagnosticsTests.cs

Note: Searched for older version constants (NET8_0_OR_GREATER, NET7_0_OR_GREATER, NET6_0_OR_GREATER, etc.) - none were found in the source files.

Original prompt

This repo no longer builds for .NET Core versions older than 10. As such, search for all occurrences of compilation constants like NET10_0_OR_GREATER, NET9_0_OR_GREATER, etc. If they're in files that also build for netstandard, replace them with just NET. If they're in files that only build for .NET 10+, whatever is protected by those constants can be unconditionally included, and anything po

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[stephentoub]

@copilot, what about NET8_0_OR_GREATER, NET7_0_OR_GREATER, NET6_0_OR_GREATER, etc. Any of those that also need to be cleaned up?

[Copilot]

@copilot, what about NET8_0_OR_GREATER, NET7_0_OR_GREATER, NET6_0_OR_GREATER, etc. Any of those that also need to be cleaned up?

I searched for NET8_0_OR_GREATER, NET7_0_OR_GREATER, NET6_0_OR_GREATER, and other older version constants in src/libraries/ (excluding tests, baselines, and gen folders). No occurrences were found - it appears those were already cleaned up previously or never existed in the source files that needed updating.

[stephentoub]

@copilot, there are build failures, e.g.

Build FAILED.

D:\a\_work\1\s\src\libraries\System.Private.CoreLib\src\System\Runtime\CompilerServices\ConfiguredCancelableAsyncEnumerable.cs(13,26): error CS9240: Target runtime doesn't support by-ref-like generics. [D:\a\_work\1\s\src\libraries\Microsoft.Bcl.AsyncInterfaces\src\Microsoft.Bcl.AsyncInterfaces.csproj::TargetFramework=netstandard2.0]
D:\a\_work\1\s\src\libraries\System.Private.CoreLib\src\System\Collections\Generic\IAsyncEnumerable.cs(11,26): error CS9240: Target runtime doesn't support by-ref-like generics. [D:\a\_work\1\s\src\libraries\Microsoft.Bcl.AsyncInterfaces\src\Microsoft.Bcl.AsyncInterfaces.csproj::TargetFramework=netstandard2.0]
D:\a\_work\1\s\src\libraries\System.Private.CoreLib\src\System\Collections\Generic\IAsyncEnumerator.cs(11,27): error CS9240: Target runtime doesn't support by-ref-like generics. [D:\a\_work\1\s\src\libraries\Microsoft.Bcl.AsyncInterfaces\src\Microsoft.Bcl.AsyncInterfaces.csproj::TargetFramework=netstandard2.0]
D:\a\_work\1\s\src\libraries\System.Private.CoreLib\src\System\Threading\Tasks\TaskAsyncEnumerableExtensions.cs(26,30): error CS9240: Target runtime doesn't support by-ref-like generics. [D:\a\_work\1\s\src\libraries\Microsoft.Bcl.AsyncInterfaces\src\Microsoft.Bcl.AsyncInterfaces.csproj::TargetFramework=netstandard2.0]
D:\a\_work\1\s\src\libraries\System.Private.CoreLib\src\System\Threading\Tasks\TaskAsyncEnumerableExtensions.cs(36,30): error CS9240: Target runtime doesn't support by-ref-like generics. [D:\a\_work\1\s\src\libraries\Microsoft.Bcl.AsyncInterfaces\src\Microsoft.Bcl.AsyncInterfaces.csproj::TargetFramework=netstandard2.0]
D:\a\_work\1\s\src\libraries\System.Private.CoreLib\src\System\Runtime\CompilerServices\ConfiguredCancelableAsyncEnumerable.cs(13,26): error CS9240: Target runtime doesn't support by-ref-like generics. [D:\a\_work\1\s\src\libraries\Microsoft.Bcl.AsyncInterfaces\src\Microsoft.Bcl.AsyncInterfaces.csproj::TargetFramework=net462]
D:\a\_work\1\s\src\libraries\System.Private.CoreLib\src\System\Collections\Generic\IAsyncEnumerable.cs(11,26): error CS9240: Target runtime doesn't support by-ref-like generics. [D:\a\_work\1\s\src\libraries\Microsoft.Bcl.AsyncInterfaces\src\Microsoft.Bcl.AsyncInterfaces.csproj::TargetFramework=net462]
D:\a\_work\1\s\src\libraries\System.Private.CoreLib\src\System\Collections\Generic\IAsyncEnumerator.cs(11,27): error CS9240: Target runtime doesn't support by-ref-like generics. [D:\a\_work\1\s\src\libraries\Microsoft.Bcl.AsyncInterfaces\src\Microsoft.Bcl.AsyncInterfaces.csproj::TargetFramework=net462]
D:\a\_work\1\s\src\libraries\System.Private.CoreLib\src\System\Threading\Tasks\TaskAsyncEnumerableExtensions.cs(26,30): error CS9240: Target runtime doesn't support by-ref-like generics. [D:\a\_work\1\s\src\libraries\Microsoft.Bcl.AsyncInterfaces\src\Microsoft.Bcl.AsyncInterfaces.csproj::TargetFramework=net462]
D:\a\_work\1\s\src\libraries\System.Private.CoreLib\src\System\Threading\Tasks\TaskAsyncEnumerableExtensions.cs(36,30): error CS9240: Target runtime doesn't support by-ref-like generics. [D:\a\_work\1\s\src\libraries\Microsoft.Bcl.AsyncInterfaces\src\Microsoft.Bcl.AsyncInterfaces.csproj::TargetFramework=net462]
D:\a\_work\1\s\src\libraries\Common\src\System\HexConverter.cs(235,27): error CS9244: The type 'HexConverter.SpanCasingPair' may not be a ref struct or a type parameter allowing ref structs in order to use it as parameter 'TState' in the generic type or method 'string.Create<TState>(int, TState, SpanAction<char, TState>)' [D:\a\_work\1\s\src\libraries\Microsoft.Bcl.Cryptography\src\Microsoft.Bcl.Cryptography.csproj::TargetFramework=netstandard2.1]
    0 Warning(s)
    11 Error(s)

[Copilot]

@copilot, there are build failures, e.g.

Build FAILED.

...

Fixed in 156bd27. The issue was that files like IAsyncEnumerable.cs, IAsyncEnumerator.cs, ConfiguredCancelableAsyncEnumerable.cs, and TaskAsyncEnumerableExtensions.cs are shared with Microsoft.Bcl.AsyncInterfaces which targets netstandard2.0 and net462. I incorrectly removed the #if NET9_0_OR_GREATER guards entirely instead of replacing them with #if NET. These files now correctly use #if NET to protect the allows ref struct constraint.

[stephentoub]

@copilot, please search the repo for any remaining NET9_0_OR_GREATER or NET10_0_OR_GREATER constants in any files.

[Copilot]

@copilot, please search the repo for any remaining NET9_0_OR_GREATER or NET10_0_OR_GREATER constants in any files.

Found and fixed 18 remaining occurrences in test files (commit 6a4b0e8):

• Common/tests/System/Security/Cryptography/ByteUtils.cs - 3 occurrences
• Common/tests/System/Security/Cryptography/X509Certificates/X509CertificateLoaderPkcs12Tests.cs - 2 occurrences
• Common/tests/System/Security/Cryptography/X509Certificates/X509CertificateLoaderPkcs12CollectionTests.cs - 2 occurrences
• Microsoft.Extensions.Caching.Memory/tests/AltLookupTests.cs - 3 occurrences
• System.Formats.Asn1/tests/Writer/PushPopSetOf.cs - 1 occurrence
• System.Formats.Asn1/tests/Writer/Asn1WriterTests.cs - 1 occurrence
• System.Formats.Asn1/tests/Writer/SimpleWriterTests.cs - 2 occurrences
• System.Text.Json/tests/Common/MetadataTests.cs - 2 occurrences
• System.Text.Json/tests/System.Text.Json.SourceGeneration.Tests/Serialization/MetadataTests.cs - 1 occurrence
• System.Text.Json/tests/System.Text.Json.SourceGeneration.Unit.Tests/JsonSourceGeneratorDiagnosticsTests.cs - 1 occurrence

All replaced with NET to maintain the .NET Core vs .NET Framework distinction. No remaining occurrences in src/libraries.

[stephentoub]

No remaining occurrences in src/libraries.

@copilot, are there remaining uses elsewhere than src/libraries?

[Copilot]

No remaining occurrences in src/libraries.

@copilot, are there remaining uses elsewhere than src/libraries?

No, there are no remaining occurrences anywhere in the repo. I searched the entire repository (excluding .git/, .dotnet/, and /docs/) for NET9_0_OR_GREATER and NET10_0_OR_GREATER in .cs, .csproj, .targets, and .props files - the search returned empty results.