Review #639.

Source/Linq/Builder/GroupByBuilder.cs

@@ -216,7 +216,7 @@ public Expression GetGrouping(GroupByContext context)
 						if (context._element.Lambda.Parameters.Count == 1                   && 
 							context._element.Body == context._element.Lambda.Parameters[0])
 						{
-							var ex = new InvalidOperationException(
+							var ex = new LinqToDBException(
 								"You should explicitly specify selected fields for server-side GroupBy() call or add AsEnumerable() call before GroupBy() to perform client-side grouping.\n" +
 								"Set Configuration.Linq.GuardGrouping = false to disable this check."
 								);

Tests/Linq/Linq/GroupByTests.cs

@@ -1841,28 +1841,35 @@ public void GroupByGuard(string context)
 				Assert.AreEqual(2, dictionary1.Count);
 				Assert.AreEqual(2, dictionary1.First().Value.Count);
 
-				Assert.Throws<InvalidOperationException>(() =>
+				var list =
+				(
+					from p in db.Person
+					group p by p.Gender into gr
+					select new { gr.Key, Count = gr.Count() }
+				)
+				.ToDictionary(_ => _.Key);
+
+				Assert.Throws<LinqToDBException>(() =>
 				{
 					// group on server
 					db.Person
 						.GroupBy(_ => _.Gender)
 						.ToDictionary(_ => _.Key, _ => _.ToList());
 				});
 
-				Assert.Throws<InvalidOperationException>(() =>
+				Assert.Throws<LinqToDBException>(() =>
 				{
 					db.Person
 						.GroupBy(_ => _)
 						.ToDictionary(_ => _.Key, _ => _.ToList());
 				});
 
-				Assert.Throws<InvalidOperationException>(() =>
+				Assert.Throws<LinqToDBException>(() =>
 				{
 					db.Person
 						.GroupBy(_ => _)
 						.ToList();
 				});
-
 			}
 		}
 	}