Refactoring between reference and struct anonymous records

[xperiandri]

Description

Stacked on #20548: this branch contains its commits; the anonymous record commits on top of them (and the merge bringing #20548's latest changes) belong to this PR.

Adds an editor refactoring (Ctrl+. inside an anonymous record expression or an annotated anonymous record type) that converts it between {| … |} and struct {| … |}, following its value through the solution the same way #20548 does for tuples:

let greet (p: {| Name: string |}) = "Hi " + p.Name

let ada = {| Name = "Ada" |}
let greetings = [ greet ada; greet {| Name = "Bob" |} ]

⟷

let greet (p: struct {| Name: string |}) = "Hi " + p.Name

let ada = struct {| Name = "Ada" |}
let greetings = [ greet ada; greet struct {| Name = "Bob" |} ]

What differs from tuples. Both forms differ only by struct in front of {|, so every change is an insertion or a removal of that keyword; there are no anonymous record patterns, and reading a field (r.Name) does not depend on the form. A copy-and-update {| r with … |} has its own form regardless of r's (the checker does not carry it over), so it converts independently: converting r leaves the copy alone, and converting the copy leaves r alone.

Engine. The propagation from #20548 is made independent of the kind of node:

• StructConversion.fs — the shared caret search and a StructKind record describing how a kind is recognized in expressions, patterns and types and how its form changes;
• TupleConversion.fs and AnonymousRecordConversion.fs — the two kinds;
• StructPropagation.fs (was TuplePropagation.fs) — the worklist over values, parameters, record fields and results, taking a StructKind, plus registerConversion, which both providers now call.

The tuple refactoring's behaviour and tests are unchanged.

Not offered inside quotations or in a file with a paired .fsi.

Covered cases

Converts

• An anonymous record used nowhere else converts on its own, and back: printfn "%A" {| A = 1 |} → printfn "%A" struct {| A = 1 |}; a type argument list<{| A: int |}> → list<struct {| A: int |}>; a multi-line {| … |} → struct {| … |}
• A value converts together with the annotations it flows into, and field access is left as is, both ways: let person = {| Name = "Ada"; Age = 36 |} + let copy: {| Name: string; Age: int |} = person + person.Age → struct {| Name = "Ada"; Age = 36 |} + let copy: struct {| Name: string; Age: int |} = person
• A parameter annotation converts every argument passed to it, both literals and values, both ways: let greet (p: {| Name: string |}) + let ada = {| Name = "Ada" |} + greet ada; greet {| Name = "Bob" |} → let greet (p: struct {| Name: string |}) + let ada = struct {| Name = "Ada" |} + greet struct {| Name = "Bob" |}
• A return type converts the result and the annotated values it is bound to, both ways: let origin () : {| X: int; Y: int |} = {| X = 0; Y = 0 |} + let start: {| X: int; Y: int |} = origin () → struct {| X: int; Y: int |} in all three places
• A record field converts only its own values and the annotations that read it, both ways: { Info: {| Age: int |}; Tags: {| Count: int |} } + { Info = {| Age = 30 |}; Tags = {| Count = 0 |} } + let info: {| Age: int |} = person.Info → only Info becomes struct {| Age: int |}, struct {| Age = 30 |} and let info: struct {| Age: int |}; Tags is not changed
• A copy-and-update expression converts separately from its source, both ways: the caret on let point = {| X = 1 |} gives struct {| X = 1 |} and leaves {| point with Y = 2 |} alone; the caret on with gives struct {| point with Y = 2 |} and leaves point alone
• A value declared in a second file converts in that file: the caret on let name (p: {| Name: string |}) + name A.person in module B also rewrites let person = {| Name = "Ada" |} in A to struct {| Name = "Ada" |}; the result is checked as a new project and has no errors
• The action titles name the target kind: Convert to struct anonymous record and Convert to reference anonymous record
• Every result is re-type-checked and asserted to have no errors

Not offered

• The caret is not on an anonymous record: let x = 1
• A normal record: type Point = { X: int } + let point = { X = 1 }
• An anonymous record inside a quotation: <@ {| A = 1 |} @>

Checklist

• Test cases added
• Performance benchmarks added in case of performance changes (not applicable)
• 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

---

✅ Found changes and release notes in following paths:

Change path	Release notes path	Description
`vsintegration/src`	docs/release-notes/.VisualStudio/18.vNext.md

[github-actions]

🔍 Tooling Safety Check — Affects-Design-Time
Affects-Design-Time: Modifies Visual Studio code executed while projects are open.

Generated by PR Tooling Safety Check · gpt56 1.8M · ◷