Bugfix :: Fix optimizer bug where field.Index included compiler generated static fields

[T-Gro]

Fixes#18165

The issue was caused by optimizer using a recordField.Index member which was also increment with compiler generated static fields, like init@5. Those should not be part of Index calculation.

There are two usages of the .Index member (I am putting them here, since GH text based diff will not show that)

• To sort fields. This remains the same if compiler generated static fields are excluded: let sortedRecdFields = unsortedRecdFields |> List.indexed |> Array.ofList |> Array.sortBy (fun (_, r) -> r.Index)
• In the optimizer path for optimizing away field get => this is the one which this fix targets and where the reported issue was coming from.

andTryOptimizeRecordFieldGet cenv _env (e1info,(RecdFieldRef (rtcref,_)as r),_tinst,m)=letg= cenv.g
match destRecdValue e1info.Info with| Some finfos when cenv.settings.EliminateRecdFieldGet &&not e1info.HasEffect ->match TryFindFSharpAttribute g g.attrib_CLIMutableAttribute rtcref.Attribs with| Some _-> None
| None ->letn= r.Index
if n >= finfos.Length then errorR(InternalError("TryOptimizeRecordFieldGet: term argument out of range", m))
Some finfos[n]

[github-actions]

❗ Release notes required

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✅ Found changes and release notes in following paths:

Change path	Release notes path	Description
src/Compiler	docs/release-notes/.FSharp.Compiler.Service/9.0.300.md