CodePlex dotnet#2252: Regression from 6.0.2 - generated SQL uses CROS…

…S APPLY instead of INNER JOIN.

We defer FilterOpRules.Rule_FilterOverOuterApply to allow the NullSemantics phase to expand EQ operations. However we do not re-run ApplyOpRules.Rule_CrossApplyOverFilter which converts the CROSS APPLY to INNER JOIN when conditions are met.
The fix adds ApplyOpRules and JoinOpRules to the deferred transformation rules.

src/EntityFramework/Core/Query/PlanCompiler/TransformationRules.cs

@@ -161,6 +161,8 @@ private static List<Rule> DeferredRules
                     deferredRules = new List<Rule>();
                     deferredRules.Add(FilterOpRules.Rule_FilterOverLeftOuterJoin);
                     deferredRules.Add(FilterOpRules.Rule_FilterOverOuterApply);
+                    deferredRules.AddRange(ApplyOpRules.Rules);
+                    deferredRules.AddRange(JoinOpRules.Rules);
                 }
                 return deferredRules;
             }

test/EntityFramework/FunctionalTests/Query/NullSemanticsTests.cs

@@ -688,12 +688,11 @@ public void EQ_is_not_expanded_when_rewriting_navigation_properties()
     [Extent1].[Id] AS [Id], 
     [Extent1].[Group] AS [Group]
     FROM  [dbo].[Orders] AS [Extent1]
-    CROSS APPLY  (SELECT [Extent2].[Group] AS [Group]
+    INNER JOIN  (SELECT [Extent2].[Group] AS [Group], [Extent4].[Id] AS [Id1]
         FROM   [dbo].[Orders] AS [Extent2]
         LEFT OUTER JOIN [dbo].[Invoices] AS [Extent3] ON [Extent2].[Id] = [Extent3].[Id]
-        INNER JOIN [dbo].[Invoices] AS [Extent4] ON [Extent4].[Id] = [Extent3].[Id]
-        WHERE [Extent1].[Id] = [Extent4].[Id] ) AS [Filter1]
-    WHERE [Filter1].[Group] < 10");
+        INNER JOIN [dbo].[Invoices] AS [Extent4] ON [Extent4].[Id] = [Extent3].[Id] ) AS [Join2] ON [Extent1].[Id] = [Join2].[Id1]
+    WHERE [Join2].[Group] < 10");
 
                     Assert.Equal(0, query.Count());
                 }