System.Core error: "Code supposed to be unreachable" using C# Entity Framework and Linq with Expression

Question

I'm getting a "Code supposed to be unreachable" error when executing the following Linq to Sql statement. I'm using EF 6.1.3. I think this is a known bug related to filtering a navigation property. It seems like it might be fixed in EF7 but I don't see anything related to this in the EF 6.2 release notes nor the EF6 open items on GitHub so I guess I'm looking for a work around, maybe a different way of writing my Linq statement.

Ultimately, I am applying the same where clause (AccountSecurity) in multiple places (also based on passing a user key parameter) so I thought I'd be able to turn it into a function that generates the Expression to use in the where clause in my Linq to Sql statement.

    public List<Company> GetCompanyList(int p_UserKey, MemberType p_MemberType)
    {
        var qry = from cs in this.DbContext.CompanySet
                  .Where(c => c.Accounts.AsQueryable().Any(this.AccountSecurity(p_UserKey)))
                  select cs;
        return qry.ToList();
    }

    private Expression<Func<Account, bool>> AccountSecurity(int p_UserKey)
    {
        return (ac => ac.UserAccounts.Any(ua => ua.UserKey == p_UserKey));
    }

Uterus

Answer 1

As a workaround, you can capture the method call into variable outside the query expression tree and use that variable inside:

var accountFilter = this.AccountSecurity(p_UserKey);
var qry = from cs in this.DbContext.CompanySet
          .Where(c => c.Accounts.AsQueryable().Any(accountFilter))
          select cs;
return qry.ToList();

Noncommittal

This doesn't fix my problem. Same error. Thanks for contributing. – Uterus

EF being EF. This did the trick for me, but I used the expression inside a Where and inside a Select, so I had to replace in both places for it to work. – Trochaic

Surprisingly for me using first a variable did the trick! Thanks a lot! – Trussell

Thank you, it helps for Any method, but for Where is not needed. Strange effect. – Zipah

@Zipah I don't think the operator (Where, Any etc.) matters, but whether it is part of top level operator or lambda expression. It's not so strange when you realize that in lambda expression (Expression<Func<…>>) like c => c.Accounts.AsQueryable().Any(this.AccountSecurity(p_UserKey)), nothing in the body (after =>) is actually executed. And IQueryable translators usually do not process unknown methods. – Noncommittal