Regression in the translation of SqlConstantExpression

[ranma42]

In EFCore 9 the construction of SqlConstantExpression from a ConstantExpression has regressed.

// @nuget: Microsoft.EntityFrameworkCore.SqlServer -Version 9.0.0
using System;
using System.Linq;
using System.Linq.Expressions;
using Microsoft.EntityFrameworkCore;
using Microsoft.EntityFrameworkCore.Query.SqlExpressions;

using var db = new BloggingContext();

var query = db.Blogs
    .Select(x => db.Fail())
    .ToQueryString();

Console.WriteLine(query);

public class BloggingContext : DbContext
{
    public DbSet<Blog> Blogs { get; set; }

    protected override void OnConfiguring(DbContextOptionsBuilder options)
        => options.UseSqlServer();

    protected override void OnModelCreating(ModelBuilder modelBuilder)
    {
        modelBuilder
            .HasDbFunction(typeof(BloggingContext).GetMethod(nameof(Fail))!)
            .HasTranslation(args => new SqlConstantExpression(Expression.Constant(true), null));
	}

    public bool Fail() => throw new NotSupportedException();
}

public class Blog
{
    public int Id { get; set; }
}

This snippet emits

SELECT NULL
FROM [Blogs] AS [b]

on EFCore 9 and

SELECT CAST(1 AS bit)
FROM [Blogs] AS [b]

on EFCore 8.

This regression seems to be caused by fbfd468#diff-31a49e080013a5417ff3104f9a840e3a5693f553c3ee840cdb7c8a4cb8e335f8R46-R50
Apparently the constructor has been marked as Obsolete, but it can still be used (which might be especially problematic if used indirectly, through a dependency).

[roji]

Thanks @ranma42 🤦