Fix DateOnly/TimeOnly design-time type resolution failure for netstandard2.0 targets

[Copilot]

When the design-time assembly (running on .NET 8) infers DateOnly/TimeOnly types, it was emitting them into generated code even for projects targeting netstandard2.0 — where those types don't exist, causing:

System.Exception: The design-time type 'System.DateOnly' utilized by a type provider
was not found in the target reference assembly set

Fix: downgrade inferred types when target doesn't support .NET 6+

Detection (Helpers.fs): runtimeSupportsNet6Types checks the runtime assembly path TFM (e.g. .../net8.0/...) to determine whether the target supports DateOnly/TimeOnly.

Downgrade functions (StructuralInference.fs): Two new internal functions — downgradeNet6Types (full InferedType tree walk) and downgradeNet6PrimitiveProperty (CSV field) — replace DateOnly→DateTime and TimeOnly→TimeSpan. Includes reference-equality cycle detection to prevent stack overflow on recursive XML type graphs.

Provider integration (CsvProvider.fs, JsonProvider.fs, XmlProvider.fs, HtmlGenerator.fs, HtmlProvider.fs): Each provider calls the appropriate downgrade function when runtimeSupportsNet6Types returns false.

Fix: XSD schema inference for xs:date

XsdInference.fs was always mapping XmlTypeCode.Date → typeof<DateTime>. Now maps to typeof<DateOnly> on .NET 6+, making schema-inferred types consistent with value-inferred types.

FSharp.Data.Xml.Core.fsproj: Added net8.0 to TargetFrameworks (was netstandard2.0 only) so #if NET6_0_OR_GREATER activates in XSD inference code.

Test updates (InferenceTests.fs)

Date-only inference expectations (e.g. "2012-12-19" → DateOnly, timestamps with time component remain DateTime) wrapped in #if NET6_0_OR_GREATER.

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[Copilot]

Just as a heads up, I was blocked by some firewall rules while working on your feedback. Expand below for details.

Warning

Firewall rules blocked me from connecting to one or more addresses (expand for details)

I tried to connect to the following addresses, but was blocked by firewall rules:

• api.worldbank.org
  • Triggering command: /usr/share/dotnet/dotnet /usr/share/dotnet/dotnet /usr/share/dotnet/sdk/8.0.123/FSharp/fsc.dll @/tmp/MSBuildTempozmhOC/tmp94e4ec414411416faaef70e64f226856.rsp (dns block)
• schemas.microsoft.com
  • Triggering command: /usr/share/dotnet/dotnet /usr/share/dotnet/dotnet exec --runtimeconfig /home/REDACTED/work/FSharp.Data/FSharp.Data/tests/FSharp.Data.DesignTime.Tests/bin/Release/net8.0/FSharp.Data.DesignTime.Tests.runtimeconfig.json --depsfile /home/REDACTED/work/FSharp.Data/FSharp.Data/tests/FSharp.Data.DesignTime.Tests/bin/Release/net8.0/FSharp.Data.DesignTime.Tests.deps.json /home/REDACTED/work/FSharp.Data/FSharp.Data/tests/FSharp.Data.DesignTime.Tests/bin/Release/net8.0/testhost.dll --port 44673 --endpoint 127.0.0.1:044673 --role client --parentprocessid 11244 --telemetryoptedin false (dns block)
  • Triggering command: /usr/share/dotnet/dotnet /usr/share/dotnet/dotnet exec --runtimeconfig /home/REDACTED/work/FSharp.Data/FSharp.Data/tests/FSharp.Data.DesignTime.Tests/bin/Release/net8.0/FSharp.Data.DesignTime.Tests.runtimeconfig.json --depsfile /home/REDACTED/work/FSharp.Data/FSharp.Data/tests/FSharp.Data.DesignTime.Tests/bin/Release/net8.0/FSharp.Data.DesignTime.Tests.deps.json /home/REDACTED/work/FSharp.Data/FSharp.Data/tests/FSharp.Data.DesignTime.Tests/bin/Release/net8.0/testhost.dll --port 39313 --endpoint 127.0.0.1:039313 --role client --parentprocessid 11395 --telemetryoptedin false (dns block)
  • Triggering command: /usr/share/dotnet/dotnet /usr/share/dotnet/dotnet exec --runtimeconfig /home/REDACTED/work/FSharp.Data/FSharp.Data/tests/FSharp.Data.DesignTime.Tests/bin/Release/net8.0/FSharp.Data.DesignTime.Tests.runtimeconfig.json --depsfile /home/REDACTED/work/FSharp.Data/FSharp.Data/tests/FSharp.Data.DesignTime.Tests/bin/Release/net8.0/FSharp.Data.DesignTime.Tests.deps.json /home/REDACTED/work/FSharp.Data/FSharp.Data/tests/FSharp.Data.DesignTime.Tests/bin/Release/net8.0/testhost.dll --port 40737 --endpoint 127.0.0.1:040737 --role client --parentprocessid 23985 --telemetryoptedin false (dns block)
• tomasp.net
  • Triggering command: /usr/share/dotnet/dotnet /usr/share/dotnet/dotnet exec --runtimeconfig /home/REDACTED/work/FSharp.Data/FSharp.Data/tests/FSharp.Data.DesignTime.Tests/bin/Release/net8.0/FSharp.Data.DesignTime.Tests.runtimeconfig.json --depsfile /home/REDACTED/work/FSharp.Data/FSharp.Data/tests/FSharp.Data.DesignTime.Tests/bin/Release/net8.0/FSharp.Data.DesignTime.Tests.deps.json /home/REDACTED/work/FSharp.Data/FSharp.Data/tests/FSharp.Data.DesignTime.Tests/bin/Release/net8.0/testhost.dll --port 44673 --endpoint 127.0.0.1:044673 --role client --parentprocessid 11244 --telemetryoptedin false (dns block)
  • Triggering command: /usr/share/dotnet/dotnet /usr/share/dotnet/dotnet exec --runtimeconfig /home/REDACTED/work/FSharp.Data/FSharp.Data/tests/FSharp.Data.DesignTime.Tests/bin/Release/net8.0/FSharp.Data.DesignTime.Tests.runtimeconfig.json --depsfile /home/REDACTED/work/FSharp.Data/FSharp.Data/tests/FSharp.Data.DesignTime.Tests/bin/Release/net8.0/FSharp.Data.DesignTime.Tests.deps.json /home/REDACTED/work/FSharp.Data/FSharp.Data/tests/FSharp.Data.DesignTime.Tests/bin/Release/net8.0/testhost.dll --port 39313 --endpoint 127.0.0.1:039313 --role client --parentprocessid 11395 --telemetryoptedin false (dns block)
  • Triggering command: /usr/share/dotnet/dotnet /usr/share/dotnet/dotnet exec --runtimeconfig /home/REDACTED/work/FSharp.Data/FSharp.Data/tests/FSharp.Data.DesignTime.Tests/bin/Release/net8.0/FSharp.Data.DesignTime.Tests.runtimeconfig.json --depsfile /home/REDACTED/work/FSharp.Data/FSharp.Data/tests/FSharp.Data.DesignTime.Tests/bin/Release/net8.0/FSharp.Data.DesignTime.Tests.deps.json /home/REDACTED/work/FSharp.Data/FSharp.Data/tests/FSharp.Data.DesignTime.Tests/bin/Release/net8.0/testhost.dll --port 40737 --endpoint 127.0.0.1:040737 --role client --parentprocessid 23985 --telemetryoptedin false (dns block)
• www.google.com
  • Triggering command: /usr/share/dotnet/dotnet /usr/share/dotnet/dotnet exec --runtimeconfig /home/REDACTED/work/FSharp.Data/FSharp.Data/tests/FSharp.Data.Core.Tests/bin/Release/net8.0/FSharp.Data.Core.Tests.runtimeconfig.json --depsfile /home/REDACTED/work/FSharp.Data/FSharp.Data/tests/FSharp.Data.Core.Tests/bin/Release/net8.0/FSharp.Data.Core.Tests.deps.json /home/REDACTED/work/FSharp.Data/FSharp.Data/tests/FSharp.Data.Core.Tests/bin/Release/net8.0/testhost.dll --port 36091 --endpoint 127.0.0.1:036091 --role client --parentprocessid 49914 --telemetryoptedin false d64.list list (dns block)
  • Triggering command: /usr/share/dotnet/dotnet /usr/share/dotnet/dotnet exec --runtimeconfig /home/REDACTED/work/FSharp.Data/FSharp.Data/tests/FSharp.Data.Core.Tests/bin/Release/net8.0/FSharp.Data.Core.Tests.runtimeconfig.json --depsfile /home/REDACTED/work/FSharp.Data/FSharp.Data/tests/FSharp.Data.Core.Tests/bin/Release/net8.0/FSharp.Data.Core.Tests.deps.json /home/REDACTED/work/FSharp.Data/FSharp.Data/tests/FSharp.Data.Core.Tests/bin/Release/net8.0/testhost.dll --port 41659 --endpoint 127.0.0.1:041659 --role client --parentprocessid 50154 --telemetryoptedin false .list (dns block)
  • Triggering command: /usr/share/dotnet/dotnet /usr/share/dotnet/dotnet exec --runtimeconfig /home/REDACTED/work/FSharp.Data/FSharp.Data/tests/FSharp.Data.Core.Tests/bin/Release/net8.0/FSharp.Data.Core.Tests.runtimeconfig.json --depsfile /home/REDACTED/work/FSharp.Data/FSharp.Data/tests/FSharp.Data.Core.Tests/bin/Release/net8.0/FSharp.Data.Core.Tests.deps.json /home/REDACTED/work/FSharp.Data/FSharp.Data/tests/FSharp.Data.Core.Tests/bin/Release/net8.0/testhost.dll --port 41555 --endpoint 127.0.0.1:041555 --role client --parentprocessid 50393 --telemetryoptedin false ekitglib-1.0.lis/usr/share/dotnet/sdk/8.0.123/MSBuild.dll 4.list uri.list (dns block)

If you need me to access, download, or install something from one of these locations, you can either:

• Configure Actions setup steps to set up my environment, which run before the firewall is enabled
• Add the appropriate URLs or hosts to the custom allowlist in this repository's Copilot coding agent settings (admins only)