NET-3878 Fix S3358 FP: Suggesting to extract ternary from EF Core select

[grosch-intl]

Description

The below code is not able to have the ternary operator extracted as it's part of a linq query, so the whole thing has to be run against each record.

Reproducer

        var query = context.Checklist
            .AsNoTracking()
            .Where(...)
            .Select(x => new {
                ReviewStatus = x.ReviewApprovedUtc.HasValue ? "Approved" : x.ReviewRejectedUtc.HasValue ? "Rejected" : x.ReviewRequestedUtc.HasValue ? "Pending" : null,              

Product and Version

SonarAnalyzer.CSharp 10.23.0.137933

[github-actions]

Internal ticket NET-3878

[martin-strecker-sonarsource]

Hi @grosch-intl, thanks for the report — confirmed as a false positive. Inside an IQueryable<T>.Select(...) lambda, the C# compiler converts the body to an Expression<Func<T, TResult>>, where statement-bodied lambdas aren't legal (CS0834) — so the rule's "extract into an independent statement" advice can't be followed.

Tracked internally as NET-3878 and a fix is up for review. It will roll out with the next analyzer release.