Attempting GroupBy navigation property throws internal KeyNotFoundException

[ajcvickers]

Should throw a better exception.

var query = context.Books.GroupBy(s => s.Author);

Unhandled exception. System.Collections.Generic.KeyNotFoundException: The given key 'Inner' was not present in the dictionary.
   at System.Collections.Generic.Dictionary`2.get_Item(TKey key)
   at Microsoft.EntityFrameworkCore.Query.SqlExpressions.SelectExpression.GetProjection(ProjectionBindingExpression projectionBindingExpression)
   at Microsoft.EntityFrameworkCore.Query.SqlExpressions.SelectExpression.PopulateGroupByTerms(Expression keySelector, List`1 groupByTerms, List`1 groupByAliases, String name)
   at Microsoft.EntityFrameworkCore.Query.SqlExpressions.SelectExpression.ApplyGrouping(Expression keySelector, Expression shaperExpression, ISqlExpressionFactory sqlExpressionFactory)
   at Microsoft.EntityFrameworkCore.Query.RelationalQueryableMethodTranslatingExpressionVisitor.TranslateGroupBy(ShapedQueryExpression source, LambdaExpression keySelector, LambdaExpression elementSelector, LambdaExpression resultSelector)
   at Microsoft.EntityFrameworkCore.Query.QueryableMethodTranslatingExpressionVisitor.VisitMethodCall(MethodCallExpression methodCallExpression)
   at Microsoft.EntityFrameworkCore.Query.RelationalQueryableMethodTranslatingExpressionVisitor.VisitMethodCall(MethodCallExpression methodCallExpression)
   at System.Linq.Expressions.MethodCallExpression.Accept(ExpressionVisitor visitor)
   at System.Linq.Expressions.ExpressionVisitor.Visit(Expression node)
   at Microsoft.EntityFrameworkCore.Query.QueryCompilationContext.CreateQueryExecutor[TResult](Expression query)
   at Microsoft.EntityFrameworkCore.Storage.Database.CompileQuery[TResult](Expression query, Boolean async)
   at Microsoft.EntityFrameworkCore.Query.Internal.QueryCompiler.CompileQueryCore[TResult](IDatabase database, Expression query, IModel model, Boolean async)
   at Microsoft.EntityFrameworkCore.Query.Internal.QueryCompiler.<>c__DisplayClass9_0`1.<Execute>b__0()
   at Microsoft.EntityFrameworkCore.Query.Internal.CompiledQueryCache.GetOrAddQuery[TResult](Object cacheKey, Func`1 compiler)
   at Microsoft.EntityFrameworkCore.Query.Internal.QueryCompiler.Execute[TResult](Expression query)
   at Microsoft.EntityFrameworkCore.Query.Internal.EntityQueryProvider.Execute[TResult](Expression expression)
   at Microsoft.EntityFrameworkCore.Query.Internal.EntityQueryable`1.GetEnumerator()
   at Program.Main() in C:\local\code\AllTogetherNow\Daily\Daily.cs:line 86

public class Author
{
    public int Id { get; set; }
    public string Name { get; set; } = default!;
}

public class Book
{
    public int Id { get; set; }
    public Author Author { get; set; } = default!;
    public int Price { get; set; }
}

public class SomeDbContext : DbContext
{
    protected override void OnConfiguring(DbContextOptionsBuilder optionsBuilder)
        => optionsBuilder
            .UseSqlServer(Your.ConnectionString, b => b.UseNetTopologySuite())
            .LogTo(Console.WriteLine, LogLevel.Information)
            .EnableSensitiveDataLogging();

    public DbSet<Book> Books => Set<Book>();
    public DbSet<Author> Authors => Set<Author>();
}

public class Program
{
    public static void Main()
    {
        using (var context = new SomeDbContext())
        {
            context.Database.EnsureDeleted();
            context.Database.EnsureCreated();

            var toast = new Author { Name = "Toast" };
            var alice = new Author { Name = "Alice" };

            context.AddRange(
                new Book { Author = alice, Price = 10 },
                new Book { Author = alice, Price = 10 },
                new Book { Author = toast, Price = 12 },
                new Book { Author = toast, Price = 12 },
                new Book { Author = toast, Price = 14 });

            context.SaveChanges();
        }

        using (var context = new SomeDbContext())
        {
            var query = context.Books.GroupBy(s => s.Author);

            foreach (var group in query)
            {
                Console.WriteLine($"Author: {group.Key}; Count = {group.Count()}");
            }
        }
    }
}

[ajcvickers]

Note from triage: we will enable this for non-JSON scenarios in EF7, and file a new backlog issue for the JSON column change.