Query: compilation error (dangling qsre) for query with SelectMany, order by and GroupBy aggregate

[maumar]

query:

                var query = (from c in ctx.Customers
                             join o in ctx.Orders.OrderBy(e => e.OrderID)
                                 on c.CustomerID equals o.CustomerID into grouping
                             from o in grouping.DefaultIfEmpty()
                             select c)
                    .GroupBy(c => c.CustomerID)
                    .Select(
                        g => new
                        {
                            g.Key,
                            Max = g.Max(c => c.City)
                        });

                var result = query.ToList();

query plan:

(QueryContext queryContext) => IEnumerable<<>f__AnonymousType218<string, string>> _InterceptExceptions(
|__ source: IEnumerable<<>f__AnonymousType218<string, string>> _Select(
|   |__ source: IEnumerable<IGrouping<string, ValueBuffer>> _GroupBy(
|   |   |__ source: IEnumerable<TransparentIdentifier<TransparentIdentifier<ValueBuffer, IEnumerable<ValueBuffer>>, ValueBuffer>> _SelectMany(
|   |   |   |__ source: IEnumerable<TransparentIdentifier<ValueBuffer, IEnumerable<ValueBuffer>>> _GroupJoin(
|   |   |   |   |__ outer: IEnumerable<ValueBuffer> _ShapedQuery(
|   |   |   |   |   |__ queryContext: queryContext, 
|   |   |   |   |   |__ shaperCommandContext: SelectExpression: 
|   |   |   |   |   |       SELECT [c0].[CustomerID]
|   |   |   |   |   |       FROM [Customers] AS [c0], 
|   |   |   |   |   |__ shaper: ValueBufferShaper), 
|   |   |   |   |__ inner: IEnumerable<ValueBuffer> _ShapedQuery(
|   |   |   |   |   |__ queryContext: queryContext, 
|   |   |   |   |   |__ shaperCommandContext: SelectExpression: 
|   |   |   |   |   |       SELECT [e2].[CustomerID]
|   |   |   |   |   |       FROM [Orders] AS [e2]
|   |   |   |   |   |       ORDER BY [e2].[OrderID], 
|   |   |   |   |   |__ shaper: ValueBufferShaper), 
|   |   |   |   |__ outerKeySelector: (ValueBuffer c) => string TryReadValue(c, 0, Customer.CustomerID), 
|   |   |   |   |__ innerKeySelector: (ValueBuffer o) => string TryReadValue(o, 0, Order.CustomerID), 
|   |   |   |   |__ resultSelector: (ValueBuffer c | IEnumerable<ValueBuffer> grouping) => TransparentIdentifier<ValueBuffer, IEnumerable<ValueBuffer>> CreateTransparentIdentifier(
|   |   |   |       |__ outer: c, 
|   |   |   |       |__ inner: grouping)), 
|   |   |   |__ collectionSelector: (TransparentIdentifier<ValueBuffer, IEnumerable<ValueBuffer>> t0) => IEnumerable<ValueBuffer> DefaultIfEmpty(t0.Inner), 
|   |   |   |__ resultSelector: (TransparentIdentifier<ValueBuffer, IEnumerable<ValueBuffer>> t0 | ValueBuffer o) => TransparentIdentifier<TransparentIdentifier<ValueBuffer, IEnumerable<ValueBuffer>>, ValueBuffer> CreateTransparentIdentifier(
|   |   |       |__ outer: t0, 
|   |   |       |__ inner: o)), 
|   |   |__ keySelector: (TransparentIdentifier<TransparentIdentifier<ValueBuffer, IEnumerable<ValueBuffer>>, ValueBuffer> t1) => string TryReadValue(t1.Outer.Outer, 0, Customer.CustomerID), 
|   |   |__ elementSelector: (TransparentIdentifier<TransparentIdentifier<ValueBuffer, IEnumerable<ValueBuffer>>, ValueBuffer> t1) => t1.Outer.Outer), 
|   |__ selector: (IGrouping<string, ValueBuffer> g) => new { 
|           g.Key, 
|           string Max(IEnumerable<string> _Select(
|           |__ source: g, 
|           |__ selector: (ValueBuffer c) =>  ---> [c] <--- .City))
|        }), 
|__ contextType: TestModels.Northwind.NorthwindRelationalContext, 
|__ logger: DiagnosticsLogger<Query>, 
|__ queryContext: queryContext)

exception:

System.ArgumentException : must be reducible node
	at System.Linq.Expressions.Expression.ReduceAndCheck()
	at System.Linq.Expressions.Expression.ReduceExtensions()
	at System.Linq.Expressions.Compiler.StackSpiller.RewriteExtensionExpression(Expression expr, Stack stack)
	at System.Linq.Expressions.Compiler.StackSpiller.RewriteExpression(Expression node, Stack stack)
	at System.Linq.Expressions.Compiler.StackSpiller.RewriteMemberExpression(Expression expr, Stack stack)
	at System.Linq.Expressions.Compiler.StackSpiller.RewriteExpression(Expression node, Stack stack)
	at System.Linq.Expressions.Compiler.StackSpiller.RewriteExpressionFreeTemps(Expression expression, Stack stack)
	at System.Linq.Expressions.Compiler.StackSpiller.Rewrite[T](Expression`1 lambda)
	at System.Linq.Expressions.Expression`1.Accept(StackSpiller spiller)
	at System.Linq.Expressions.Compiler.StackSpiller.RewriteLambdaExpression(Expression expr, Stack stack)
	at System.Linq.Expressions.Compiler.StackSpiller.RewriteExpression(Expression node, Stack stack)
	at System.Linq.Expressions.Compiler.StackSpiller.ChildRewriter.Add(Expression node)
	at System.Linq.Expressions.Compiler.StackSpiller.ChildRewriter.AddArguments(IArgumentProvider expressions)
	at System.Linq.Expressions.Compiler.StackSpiller.RewriteMethodCallExpression(Expression expr, Stack stack)
	at System.Linq.Expressions.Compiler.StackSpiller.RewriteExpression(Expression node, Stack stack)
	at System.Linq.Expressions.Compiler.StackSpiller.ChildRewriter.Add(Expression node)
	at System.Linq.Expressions.Compiler.StackSpiller.ChildRewriter.AddArguments(IArgumentProvider expressions)
	at System.Linq.Expressions.Compiler.StackSpiller.RewriteMethodCallExpression(Expression expr, Stack stack)
	at System.Linq.Expressions.Compiler.StackSpiller.RewriteExpression(Expression node, Stack stack)
	at System.Linq.Expressions.Compiler.StackSpiller.ChildRewriter.Add(Expression node)
	at System.Linq.Expressions.Compiler.StackSpiller.ChildRewriter.AddArguments(IArgumentProvider expressions)
	at System.Linq.Expressions.Compiler.StackSpiller.RewriteNewExpression(Expression expr, Stack stack)
	at System.Linq.Expressions.Compiler.StackSpiller.RewriteExpression(Expression node, Stack stack)
	at System.Linq.Expressions.Compiler.StackSpiller.RewriteExpressionFreeTemps(Expression expression, Stack stack)
	at System.Linq.Expressions.Compiler.StackSpiller.Rewrite[T](Expression`1 lambda)
	at System.Linq.Expressions.Expression`1.Accept(StackSpiller spiller)
	at System.Linq.Expressions.Compiler.StackSpiller.RewriteLambdaExpression(Expression expr, Stack stack)
	at System.Linq.Expressions.Compiler.StackSpiller.RewriteExpression(Expression node, Stack stack)
	at System.Linq.Expressions.Compiler.StackSpiller.ChildRewriter.Add(Expression node)
	at System.Linq.Expressions.Compiler.StackSpiller.ChildRewriter.AddArguments(IArgumentProvider expressions)
	at System.Linq.Expressions.Compiler.StackSpiller.RewriteMethodCallExpression(Expression expr, Stack stack)
	at System.Linq.Expressions.Compiler.StackSpiller.RewriteExpression(Expression node, Stack stack)
	at System.Linq.Expressions.Compiler.StackSpiller.ChildRewriter.Add(Expression node)
	at System.Linq.Expressions.Compiler.StackSpiller.ChildRewriter.AddArguments(IArgumentProvider expressions)
	at System.Linq.Expressions.Compiler.StackSpiller.RewriteMethodCallExpression(Expression expr, Stack stack)
	at System.Linq.Expressions.Compiler.StackSpiller.RewriteExpression(Expression node, Stack stack)
	at System.Linq.Expressions.Compiler.StackSpiller.RewriteExpressionFreeTemps(Expression expression, Stack stack)
	at System.Linq.Expressions.Compiler.StackSpiller.Rewrite[T](Expression`1 lambda)
	at System.Linq.Expressions.Expression`1.Accept(StackSpiller spiller)
	at System.Linq.Expressions.Compiler.LambdaCompiler.Compile(LambdaExpression lambda, DebugInfoGenerator debugInfoGenerator)
	at System.Linq.Expressions.Expression`1.Compile()
	at Microsoft.EntityFrameworkCore.Query.EntityQueryModelVisitor.CreateExecutorLambda[TResults]()
	at Microsoft.EntityFrameworkCore.Query.RelationalQueryModelVisitor.CreateExecutorLambda[TResults]()
	at Microsoft.EntityFrameworkCore.Query.EntityQueryModelVisitor.CreateQueryExecutor[TResult](QueryModel queryModel)
	at Microsoft.EntityFrameworkCore.Storage.Database.CompileQuery[TResult](QueryModel queryModel)
	--- End of stack trace from previous location where exception was thrown ---
	at System.Runtime.ExceptionServices.ExceptionDispatchInfo.Throw()
	at Microsoft.EntityFrameworkCore.Query.Internal.QueryCompiler.CompileQueryCore[TResult](Expression query, IQueryModelGenerator queryModelGenerator, IDatabase database, IDiagnosticsLogger`1 logger, Type contextType)
	at Microsoft.EntityFrameworkCore.Query.Internal.QueryCompiler.<>c__DisplayClass13_0`1.<Execute>b__0()
	at Microsoft.EntityFrameworkCore.Query.Internal.CompiledQueryCache.GetOrAddQueryCore[TFunc](Object cacheKey, Func`1 compiler)
	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 Remotion.Linq.QueryableBase`1.GetEnumerator()
	at System.Collections.Generic.List`1..ctor(IEnumerable`1 collection)
	at System.Linq.Enumerable.ToList[TSource](IEnumerable`1 source)

[maumar]

could be same underlying issue as #12794

[divega]

As per triage discussion, removing propose-punt. IIRC, we said this will likely going to be fixed for 3.0.

[smitpatel]

Enabled test GroupJoin_GroupBy_Aggregate_2