[xperiandri]

Stacked on #20894

A query composed over a tuple or record projection, such as a Where on the result of select (c.Id, c.Name), now translates in EF Core, and Cosmos accepts tuple, record and anonymous record projections.

Details

• Tuples, struct tuples, records and anonymous records were built with Expression.New and no Members, so a provider could not tell which argument a later read of Item1 or of a field refers to. They now name their members, as C# anonymous types do.
• A record whose getters are not public is built as before.
• EF Core now translates the final tuple of a query on the server where it used to build it on the client. With EF Core 10 on SQL Server, a few multi-join queries that it translates with a lateral join then fail inside EF Core with "Nullable object must have a value".

🤖 Generated with Claude Code

[github-actions]

✅ Release notes checked

---

✅ Found changes and release notes in following paths:

Change path	Release notes path	Description
`src/FSharp.Core`	docs/release-notes/.FSharp.Core/11.0.200.md

[xperiandri]

Covered cases

EF Core SQLite translates 104 of 142 scenarios, 91 without this change. Now translated: Where, OrderBy and GroupBy reading a record or an anonymous record, a Where over a query that selects a record, a tuple, struct tuple or tuple of nine taken apart by the next for, a record or anonymous record read by the next for, and exists over two fors.

Cosmos translates 46 scenarios, up from 17: every tuple, struct tuple, record and anonymous record projection. With the other PRs of the stack merged in, these projections were also run against the Cosmos emulator and came back as the tuples and records the query selects.

[Copilot]

🟡 Changes recommended

Active issues leave unnamed-member detection incomplete for nested and identity-select query chains and break constructor conversion for public marker types without ItemN properties.

3 open issues

• Limit ItemN ordering to FSharp anonymous object constructors · New
• Track unnamed-member provenance through nested and secondary query sources · New
• Preserve unnamed provenance through identity Select · New

What changed in this PR

This PR improves FSharp.Core’s LINQ expression trees so providers can connect tuple and record member reads to projected constructor arguments. It builds on #20894’s struct-tuple support and query-shape tests.

Changes:

• Name constructor members for tuples, struct tuples, records, and anonymous records, preserving the fallback for non-public record getters.
• Carry struct-tuple identity through query conversion and support field-based element access.
• Add projection assertions, query-shape scenarios, and release notes describing the expression-tree change.

File	Description
tests/​FSharp.Core.UnitTests/​FSharp.Core/​Microsoft.FSharp.Linq/​QueryStructureScenarios.fs	Cover loops, subqueries, and left joins.
tests/​FSharp.Core.UnitTests/​FSharp.Core/​Microsoft.FSharp.Linq/​QueryShapeTests.fs	Run the query scenario groups.
tests/​FSharp.Core.UnitTests/​FSharp.Core/​Microsoft.FSharp.Linq/​QueryScenarioDomain.fs	Supply shared query data and projection types.
tests/​FSharp.Core.UnitTests/​FSharp.Core/​Microsoft.FSharp.Linq/​QueryScenario.fs	Compare results and expected tree violations.
tests/​FSharp.Core.UnitTests/​FSharp.Core/​Microsoft.FSharp.Linq/​QueryProviderShape.fs	Capture queries and detect provider-shape problems.
tests/​FSharp.Core.UnitTests/​FSharp.Core/​Microsoft.FSharp.Linq/​QueryProjectionScenarios.fs	Cover tuple and record projections.
tests/​FSharp.Core.UnitTests/​FSharp.Core/​Microsoft.FSharp.Linq/​QueryOperatorScenarios.fs	Cover query operators and aggregates.
tests/​FSharp.Core.UnitTests/​FSharp.Core/​Microsoft.FSharp.Linq/​QueryMethodSyntaxScenarios.fs	Cover method-syntax projections and composition.
tests/​FSharp.Core.UnitTests/​FSharp.Core/​Microsoft.FSharp.Linq/​QueryKeyScenarios.fs	Cover composite join and grouping keys.
tests/​FSharp.Core.UnitTests/​FSharp.Core/​Microsoft.FSharp.Linq/​ExpressionNewMembersTests.fs	Assert constructor-member metadata and private-record fallback.
tests/​FSharp.Core.UnitTests/​FSharp.Core.UnitTests.fsproj	Register the new tests in compilation order.
src/​FSharp.Core/​QueryExtensions.fs	Adapt struct tuples while preserving their identity.
src/​FSharp.Core/​Query.fs	Reconstruct struct tuples in query results.
src/​FSharp.Core/​Linq.fs	Emit named constructor members and struct-tuple field reads.
docs/​release-notes/​PENDING_BREAKING_CHANGES.md	Document the changed expression-tree shape.
docs/​release-notes/​.FSharp.Core/​11.0.200.md	Record struct-tuple and projection improvements.

_{Review effort: Balanced}

[pcshrosbree]

At the current head, nothing that EF Core translated on #20894 stops translating in my probes, and previously failing queries now translate with the right rows. Please clarify the dependencies and the SQL Server failures described below, and document and test the distinct fix. I checked EF Core 10.0.14 with SQLite execution and with SQL Server translation only.

• The release note links #3782 as fixed, but its record example still fails with this PR alone. For a record declared { BId; BName }, the query select { BName = b.Name; BId = b.Id } throws NotSupportedException. The out-of-order fields produce a block, which this PR doesn't translate. {| Name = b.Name; Id = b.Id |} fails the same way. Both translate with #20895, which fixes them on its own. Please attribute this part of #3782 to #20895.
• The description says some multi-join queries now fail on SQL Server with "Nullable object must have a value", but PENDING_BREAKING_CHANGES doesn't mention it. I couldn't check that execution failure without a server. The fifteen lateral and left-join shapes I tried compile to the same SQL as on #20894, apart from column aliases. A list of the affected shapes would help.
• for (city, id) in (select (b.Address.City, b.Id)) do groupBy city into g; select (g.Key, g.Count()) used to fail with EF's "could not be translated"; now it fails inside EF Core with KeyNotFoundException: The given key 'Item1' was not present in the dictionary. With #20899 merged it translates, so this could be stated as a dependency.
• This PR also fixes a wrong result. for (city, _) in (select (b.Address.City, b.Id)) do select city; distinct returns London; London; Paris on main, from SELECT DISTINCT "b"."Address_City", "b"."Id", and London; Paris here. It deserves a release-note line and a scenario that checks the rows.
• The generated SQL now names its columns (SELECT "b"."Id" AS "Item1", ..), which SQL snapshot tests will notice.