Record the parameter and type parameter counts of a navigable item

[xperiandri]

Description

Navigate To orders matches of the same kind by a secondary sort. For C# and VB that key holds each declaration's parameter and type parameter counts, taken from Roslyn's declaration index, after the folder distance to the file being edited. dotnet/roslyn#85280 computes the same key for F# results, and needs F# to supply the two counts.

NavigateTo.GetNavigableItems is where F# builds its declaration list from the parse tree, so NavigableItem now carries:

• ParameterCount: every curried and tupled argument of the method the declaration compiles to. An instance member's self argument is not counted, and neither is a solitary unit argument: let f () = … and val f: unit -> int count 0, let f () x = … counts 2. Bindings take it from the arity the parser inferred. For signatures, the parser leaves a solitary unit argument in the arity, so it is recognised from the type.
• TypeParameterCount: the explicitly declared type parameters of a type, binding or signature.

This changes the public surface: NavigableItem is a record, so code that constructs one must supply the two fields.

Checklist

• Test cases added: NavigateToTests covers values, curried, tupled and unit functions, generic functions, types, instance and static members and properties, in implementation and signature files.
• Performance benchmarks added in case of performance changes
• Release notes entry updated

🤖 Generated with Claude Code

[github-actions]

❗ Release notes required

You can open this PR in browser to add release notes: open in github.dev

@xperiandri,

Caution

No release notes found for the changed paths (see table below).

Please make sure to add an entry with an informative description of the change as well as link to this pull request, issue and language suggestion if applicable. Release notes for this repository are based on Keep A Changelog format.

The following format is recommended for this repository:

`* . (PR #XXXXX)`

See examples in the files, listed in the table below or in th full documentation at https://fsharp.github.io/fsharp-compiler-docs/release-notes/About.html.

If you believe that release notes are not necessary for this PR, please add NO_RELEASE_NOTES label to the pull request.

Change path	Release notes path	Description
`src/Compiler`	docs/release-notes/.FSharp.Compiler.Service/11.0.200.md	No release notes found or release notes format is not correct

[T-Gro]

🤖 🕵️ AI review — verify independently.

[T-Gro]

🤖 🕵️ Named unit parameter counted as 1 in the signature but 0 in the implementation — different Navigate To sort keys for the same zero-argument method.

// NamedUnit.fsi
module NamedUnit
val Search : u: unit -> int

// NamedUnit.fs
module NamedUnit
let Search () = 1

[T-Gro]

I am afraid this might alltogether operate on a wrong layer, considering things like:

• unit
• byrefs
• units of measure

This should follow existing functions that know how a function is represented in IL.

[xperiandri]

The layer is forced by what the caller is: NavigateTo.GetNavigableItems runs on a parse tree alone. Navigate To has to answer for every document in the solution, and it has to answer while the solution is still loading, so no checking has happened and there is no Val, no TType, nothing the arity functions (GetTopValTypeInFSharpForm, ArgInfosOfMember) could be handed. Reaching for them here would mean checking every document in the solution to fill in a sort tiebreak.

That is also the layer the numbers are compared against. They exist for NavigateToSearchResultHelpers.ComputeSecondarySort, which orders results that already matched the pattern equally well, and C# and Visual Basic fill them the same way — CSharpDeclaredSymbolInfoFactoryService takes ParameterList.Parameters.Count and TypeParameterList?.Parameters.Count straight off the declaration syntax. A wrong count moves one same-named result past another in that list; it is never asked whether two members are the same member.

On the three you named:

• byrefs — a byref parameter is still one parameter in IL, so the count is unaffected;
• units of measure — a measure annotates the type of a parameter and adds none, so likewise;
• unit — this one really does differ, and it is the only one that does. A solitary unit argument is dropped by the compiler but left in the arity the parser produces for a signature, so val f : unit -> int and let f () = 1 disagreed. That is handled.

The remaining hole is the named form the bot found in the other thread, val Search : u: unit -> int: the check looks through SynType.Paren and SynType.WithGlobalConstraints but not through SynType.SignatureParameter, so a named unit still counts as one. Fixing that, and adding both spellings to the tests.

If the team would rather the two numbers be IL-accurate, then they cannot come from this walker at all and the tiebreak needs a different source — happy to take that route instead, but it is a different change from this one.

[Copilot]

Copilot review overview

🟡 Changes recommended

Two correctness issues remain in parameter-count computation, and the release note is in the wrong version file.

Review effort: Lite
Findings: 1

Open (1)

• Unwrap labeled signature parameters when counting unit arguments · New

What changed in this PR

Adds parameter and type-parameter counts to F# NavigableItem results for consistent Navigate To ordering.

Changes:

• Computes counts from implementation and signature syntax.
• Extends the public API and surface-area baseline.
• Adds comprehensive tests and release notes.

File	Summary
tests/​FSharp.Compiler.Service.Tests/​NavigateToTests.fs	Adds coverage for declaration count behavior.
tests/​FSharp.Compiler.Service.Tests/​FSharp.Compiler.Service.Tests.fsproj	Includes the updated tests.
tests/​FSharp.Compiler.Service.Tests/​FSharp.Compiler.Service.SurfaceArea.netstandard20.bsl	Updates the API baseline.
src/​Compiler/​Service/​ServiceNavigation.fsi	Exposes and documents the new fields.
src/​Compiler/​Service/​ServiceNavigation.fs	Computes declaration counts; labeled unit signatures and property setters require corrections (moderate, 3 and 1 votes).
docs/​release-notes/​.FSharp.Compiler.Service/​11.0.100.md	Adds release notes, but the entry should move to the current 11.0.200 file (nit, 1 vote).

[github-actions]

🔍 Tooling Safety Check — Affects-Design-Time
Affects-Design-Time: Changes Navigate To declaration metadata.

Generated by PR Tooling Safety Check · gpt56 913.7K · ◷