F# codegen: emit a named this self identifier (#393)

[jeremydmiller]

Closes #393.

Problem

Generated F# members were emitted as member _.X(...), discarding the self identifier. C# generated handlers routinely call inherited instance members unqualified (relying on implicit this) — e.g. a Wolverine.Http.HttpHandler subclass calls the base instance ReadJsonAsync/WriteJsonAsync, and a MessageHandler subclass calls RecordCauseAndEffect. F# has no implicit this, so member _. left those calls unresolvable, blocking the Wolverine F# audit's HTTP JSON path (JasperFx/wolverine#2969, Phase C).

Fix

• GeneratedMethod.WriteFSharpMethod now emits member this. / override this.. F# does not warn on an unused member self identifier (unlike an unused let binding), so the original unused-this concern doesn't apply, and the F# fixtures don't run warnings-as-errors.
• MethodCall F# emit renders IsLocal calls as this.method(...) (was the empty prefix), matching the implicit-this semantics of the C# path.

Test

A new GeneratedCalculator fixture type overrides a base abstract method and calls the inherited instance Bump via a local MethodCall, so the compile gate proves the emitted F# compiles:

type GeneratedCalculator() =
    inherit FSharpCodegenTarget.CalculatorBase()
    override this.Compute(seed: int) : int =
        let result_of_Bump = this.Bump(seed)
        result_of_Bump

The four FSharpGenerationTests self-identifier assertions were updated member _. → member this..

Verification

• CodegenTests F# generation/unit tests: 30/30 pass (net9.0 + net10.0).
• CodegenTests.FSharp compile gate: the regenerated Generated.fs (now this. throughout, incl. the new inherited-call case) compiles via dotnet build on both TFMs.

🤖 Generated with Claude Code