Support new .NET LINQ features

[roji]

• [ ] #24479
• [ ] #28634
• [ ] #25566
• [ ] #25569
• [ ] #27470

[radderz]

Is it possible to add to this the support of .ToDictionary() during a projection given that it is a Linq feature that is missing? #25986

[roji]

@radderz the above list is about supporting new LINQ operators introduced in .NET. There's nothing new about using ToDictionary in a projection - it's just not something EF Core doesn't currently support. The idea wasn't for this list to track any construct that isn't yet translated.

[John0King]

Can we simply have an IQueryable<T>.LeftJoin<T,T1,Tkey,TReturn>(IQueryable<T1> joinSource, Expression<Func<T,Tkey> outer, Expresion<Func<T,Tkey>> inner, JoinOperator @operator, Expression<Func<T1,T2,TReturn> selector) method?

[roji]

@John0King that is tracked by #12793, and would be a new EF Core operator rather than supporting existing LINQ operators.

[thorgeirk11]

What about the new DistinctBy?

[roji]

@thorgeirk11 thanks, opened #27470 to track that, and posted some preliminary analysis.

[luciniga]

I know this is old, but do you have any plans on adding support for string.Join? See #2981

[roji]

@luciniga string.Join isn't a LINQ operator, it's just another .NET function that can be used within LINQ operators. It's tracked by #2981, which is currently in the Backlog, meaning that it isn't in the plan for 7.0.