F# interface-stub generator re-offers a property already implemented via explicit get/set accessors

What

Given an interface member abstract member Value: int with get, set implemented as:

type BothAccessors() =
    let mutable current = 0
    interface IStore with
        member _.Value
            with get () = current
            and set value = current <- value

FSharpCodeActions.tryGenerateInterfaceStub still offers Value among the members to generate. Accepting the fix would emit a second Value beside the existing accessors, which does not compile.

This is the implementation being complete, not a partial one

Confirmed against the compiler — the with get () = ... and set v = ... form does fully satisfy abstract member Value: int with get, set. A standalone project containing exactly the type above plus member _.Reset() = ... builds with 0 errors. So the member really is implemented and should be excluded from the candidate set.

The genuinely-partial forms behave correctly: a getter-only or setter-only implementation leaves the other half outstanding, and offering Value again there is right.

Where

implementedMemberSignatures / the candidate scan in FSharpCodeActions.fs appears not to recognise a SynMemberDefn.GetSetMember carrying both accessors as satisfying both halves of the abstract property.

Tests

FSharpAccessorStubTests covers the three accessor shapes. The get/set case deliberately asserts only that the genuinely missing Reset is offered, rather than pinning the duplicate Value as expected behaviour — so it will not need weakening when this is fixed, only strengthening with Assert.DoesNotContain("Value", text).

Notes

Pre-existing, not a regression from #200. Found while closing that PR's F# coverage gap.

Start in FSharpCodeActions.fs at implementedMemberSignatures and the candidate scan, then inspect the get/set cases in FSharpAccessorStubTests. Run the accessor stub tests first. Update handling for a SynMemberDefn.GetSetMember with both accessors so the completed Value is not offered while the missing Reset remains available, and verify getter-only and setter-only cases still offer the incomplete member.