CSHARP-4048: Test ALL IEnumerable extension methods against IGrouping.

Author: rstam

src/MongoDB.Driver/Linq/Linq3Implementation/Ast/Expressions/AstNaryExpression.cs

@@ -49,7 +49,20 @@ public override AstNode Accept(AstNodeVisitor visitor)
 
         public override BsonValue Render()
         {
-            return new BsonDocument(_operator.Render(), new BsonArray(_args.Select(e => e.Render())));
+            BsonValue renderedArgs;
+            if (_args.Count == 1)
+            {
+                renderedArgs = _args[0].Render();
+                if (renderedArgs.BsonType == BsonType.Array)
+                {
+                    renderedArgs = new BsonArray { renderedArgs };
+                }
+            }
+            else
+            {
+                renderedArgs = new BsonArray(_args.Select(e => e.Render()));
+            }
+            return new BsonDocument(_operator.Render(), renderedArgs);
         }
 
         public AstNaryExpression Update(IEnumerable<AstExpression> args)

src/MongoDB.Driver/Linq/Linq3Implementation/Reflection/EnumerableMethod.cs

@@ -24,7 +24,7 @@ namespace MongoDB.Driver.Linq.Linq3Implementation.Reflection
     internal static class EnumerableMethod
     {
         // private static fields
-        private static readonly MethodInfo __aggregate;
+        private static readonly MethodInfo __aggregateWithFunc;
         private static readonly MethodInfo __aggregateWithSeedAndFunc;
         private static readonly MethodInfo __aggregateWithSeedFuncAndResultSelector;
         private static readonly MethodInfo __all;
@@ -173,7 +173,7 @@ internal static class EnumerableMethod
         // static constructor
         static EnumerableMethod()
         {
-            __aggregate = ReflectionInfo.Method((IEnumerable<object> source, Func<object, object, object> func) => source.Aggregate(func));
+            __aggregateWithFunc = ReflectionInfo.Method((IEnumerable<object> source, Func<object, object, object> func) => source.Aggregate(func));
             __aggregateWithSeedAndFunc = ReflectionInfo.Method((IEnumerable<object> source, object seed, Func<object, object, object> func) => source.Aggregate(seed, func));
             __aggregateWithSeedFuncAndResultSelector = ReflectionInfo.Method((IEnumerable<object> source, object seed, Func<object, object, object> func, Func<object, object> resultSelector) => source.Aggregate(seed, func, resultSelector));
             __all = ReflectionInfo.Method((IEnumerable<object> source, Func<object, bool> predicate) => source.All(predicate));
@@ -321,7 +321,7 @@ static EnumerableMethod()
         }
 
         // public properties
-        public static MethodInfo Aggregate => __aggregate;
+        public static MethodInfo AggregateWithFunc => __aggregateWithFunc;
         public static MethodInfo AggregateWithSeedAndFunc => __aggregateWithSeedAndFunc;
         public static MethodInfo AggregateWithSeedFuncAndResultSelector => __aggregateWithSeedFuncAndResultSelector;
         public static MethodInfo All => __all;

src/MongoDB.Driver/Linq/Linq3Implementation/Translators/ExpressionToAggregationExpressionTranslators/ArrayIndexExpressionToAggregationExpressionTranslator.cs

@@ -26,7 +26,7 @@ public static AggregationExpression Translate(TranslationContext context, Binary
             if (expression.NodeType == ExpressionType.ArrayIndex)
             {
                 var arrayExpression = expression.Left;
-                var arrayTranslation = ExpressionToAggregationExpressionTranslator.Translate(context, arrayExpression);
+                var arrayTranslation = ExpressionToAggregationExpressionTranslator.TranslateEnumerable(context, arrayExpression);
                 var indexExpression = expression.Right;
                 var indexTranslation = ExpressionToAggregationExpressionTranslator.Translate(context, indexExpression);
                 var ast = AstExpression.ArrayElemAt(arrayTranslation.Ast, indexTranslation.Ast);

src/MongoDB.Driver/Linq/Linq3Implementation/Translators/ExpressionToAggregationExpressionTranslators/MethodTranslators/AggregateMethodToAggregationExpressionTranslator.cs

@@ -26,7 +26,7 @@ internal static class AggregateMethodToAggregationExpressionTranslator
     {
         private static readonly MethodInfo[] __aggregateMethods =
         {
-            EnumerableMethod.Aggregate,
+            EnumerableMethod.AggregateWithFunc,
             EnumerableMethod.AggregateWithSeedAndFunc,
             EnumerableMethod.AggregateWithSeedFuncAndResultSelector
         };
@@ -39,10 +39,10 @@ public static AggregationExpression Translate(TranslationContext context, Method
             if (method.IsOneOf(__aggregateMethods))
             {
                 var sourceExpression = arguments[0];
-                var sourceTranslation = ExpressionToAggregationExpressionTranslator.Translate(context, sourceExpression);
+                var sourceTranslation = ExpressionToAggregationExpressionTranslator.TranslateEnumerable(context, sourceExpression);
                 var itemSerializer = ArraySerializerHelper.GetItemSerializer(sourceTranslation.Serializer);
 
-                if (method.Is(EnumerableMethod.Aggregate))
+                if (method.Is(EnumerableMethod.AggregateWithFunc))
                 {
                     var funcLambda = (LambdaExpression)arguments[1];
                     var funcParameters = funcLambda.Parameters;

src/MongoDB.Driver/Linq/Linq3Implementation/Translators/ExpressionToAggregationExpressionTranslators/MethodTranslators/AllMethodToAggregationExpressionTranslator.cs

@@ -31,7 +31,7 @@ public static AggregationExpression Translate(TranslationContext context, Method
             if (method.Is(EnumerableMethod.All))
             {
                 var sourceExpression = arguments[0];
-                var sourceTranslation = ExpressionToAggregationExpressionTranslator.Translate(context, sourceExpression);
+                var sourceTranslation = ExpressionToAggregationExpressionTranslator.TranslateEnumerable(context, sourceExpression);
 
                 var predicateLambda = (LambdaExpression)arguments[1];
                 var predicateParameter = predicateLambda.Parameters[0];

src/MongoDB.Driver/Linq/Linq3Implementation/Translators/ExpressionToAggregationExpressionTranslators/MethodTranslators/AnyMethodToAggregationExpressionTranslator.cs

@@ -29,7 +29,7 @@ public static AggregationExpression Translate(TranslationContext context, Method
             var arguments = expression.Arguments;
 
             var sourceExpression = arguments[0];
-            var sourceTranslation = ExpressionToAggregationExpressionTranslator.Translate(context, sourceExpression);
+            var sourceTranslation = ExpressionToAggregationExpressionTranslator.TranslateEnumerable(context, sourceExpression);
 
             if (method.Is(EnumerableMethod.Any))
             {

src/MongoDB.Driver/Linq/Linq3Implementation/Translators/ExpressionToAggregationExpressionTranslators/MethodTranslators/ConcatMethodToAggregationExpressionTranslator.cs

@@ -31,9 +31,9 @@ public static AggregationExpression Translate(TranslationContext context, Method
             if (method.Is(EnumerableMethod.Concat))
             {
                 var firstExpression = arguments[0];
-                var firstTranslation = ExpressionToAggregationExpressionTranslator.Translate(context, firstExpression);
+                var firstTranslation = ExpressionToAggregationExpressionTranslator.TranslateEnumerable(context, firstExpression);
                 var secondExpression = arguments[1];
-                var secondTranslation = ExpressionToAggregationExpressionTranslator.Translate(context, secondExpression);
+                var secondTranslation = ExpressionToAggregationExpressionTranslator.TranslateEnumerable(context, secondExpression);
                 var ast = AstExpression.ConcatArrays(firstTranslation.Ast, secondTranslation.Ast);
                 var itemSerializer = ArraySerializerHelper.GetItemSerializer(firstTranslation.Serializer);
                 var serializer = IEnumerableSerializer.Create(itemSerializer);

src/MongoDB.Driver/Linq/Linq3Implementation/Translators/ExpressionToAggregationExpressionTranslators/MethodTranslators/ContainsMethodToAggregationExpressionTranslator.cs

@@ -82,7 +82,7 @@ private static bool IsEnumerableContainsMethod(MethodCallExpression expression,
 
         private static AggregationExpression TranslateEnumerableContains(TranslationContext context, Expression expression, Expression sourceExpression, Expression valueExpression)
         {
-            var sourceTranslation = ExpressionToAggregationExpressionTranslator.Translate(context, sourceExpression);
+            var sourceTranslation = ExpressionToAggregationExpressionTranslator.TranslateEnumerable(context, sourceExpression);
             var valueTranslation = ExpressionToAggregationExpressionTranslator.Translate(context, valueExpression);
             var ast = AstExpression.In(valueTranslation.Ast, sourceTranslation.Ast);
             return new AggregationExpression(expression, ast, new BooleanSerializer());

src/MongoDB.Driver/Linq/Linq3Implementation/Translators/ExpressionToAggregationExpressionTranslators/MethodTranslators/DefaultIfEmptyMethodToAggregationExpressionTranslator.cs

@@ -32,7 +32,7 @@ public static AggregationExpression Translate(TranslationContext context, Method
             if (method.IsOneOf(EnumerableMethod.DefaultIfEmpty, EnumerableMethod.DefaultIfEmptyWithDefaultValue))
             {
                 var sourceExpression = arguments[0];
-                var sourceTranslation = ExpressionToAggregationExpressionTranslator.Translate(context, sourceExpression);
+                var sourceTranslation = ExpressionToAggregationExpressionTranslator.TranslateEnumerable(context, sourceExpression);
                 var sourceVar = AstExpression.Var("source");
                 var sourceVarBinding = AstExpression.VarBinding(sourceVar, sourceTranslation.Ast);
                 AstExpression defaultValueAst;

src/MongoDB.Driver/Linq/Linq3Implementation/Translators/ExpressionToAggregationExpressionTranslators/MethodTranslators/DistinctMethodToAggregationExpressionTranslator.cs

@@ -30,7 +30,7 @@ public static AggregationExpression Translate(TranslationContext context, Method
             if (method.Is(EnumerableMethod.Distinct))
             {
                 var sourceExpression = arguments[0];
-                var sourceTranslation = ExpressionToAggregationExpressionTranslator.Translate(context, sourceExpression);
+                var sourceTranslation = ExpressionToAggregationExpressionTranslator.TranslateEnumerable(context, sourceExpression);
                 var ast = AstExpression.SetIntersection(sourceTranslation.Ast);
                 return new AggregationExpression(expression, ast, sourceTranslation.Serializer);
             }