Simplify TRUE = expr in filtering contexts

src/EFCore.Relational/Query/SqlNullabilityProcessor.cs

@@ -1174,6 +1174,29 @@ protected virtual SqlExpression VisitSqlBinary(
         bool allowOptimizedExpansion,
         out bool nullable)
     {
+        // Most optimizations are done in OptimizeComparison below, but this one
+        // benefits from being done early.
+        // Consider query: (x.NullableString == "Foo") == true
+        // We recursively visit Left and Right, but when processing the left
+        // side, allowOptimizedExpansion would be set to false (we only allow it
+        // to trickle down to child nodes for AndAlso & OrElse operations), so
+        // the comparison would get unnecessarily expanded. In order to avoid
+        // this, we would need to modify the allowOptimizedExpansion calculation
+        // to capture this scenario and then flow allowOptimizedExpansion to
+        // OptimizeComparison. Instead, we just do the optimization right away
+        // and the resulting code is clearer.
+        if (allowOptimizedExpansion && sqlBinaryExpression.OperatorType == ExpressionType.Equal)
+        {
+            if (IsTrue(sqlBinaryExpression.Left) && sqlBinaryExpression.Left.TypeMapping!.Converter == null)
+            {
+                return Visit(sqlBinaryExpression.Right, allowOptimizedExpansion, out nullable);
+            }
+            else if (IsTrue(sqlBinaryExpression.Right) && sqlBinaryExpression.Right.TypeMapping!.Converter == null)
+            {
+                return Visit(sqlBinaryExpression.Left, allowOptimizedExpansion, out nullable);
+            }
+        }
+
         var optimize = allowOptimizedExpansion;
 
         allowOptimizedExpansion = allowOptimizedExpansion

test/EFCore.Relational.Specification.Tests/Query/NullSemanticsQueryTestBase.cs

@@ -402,6 +402,23 @@ join e2 in ss.Set<NullSemanticsEntity2>() on e1.NullableIntA equals e2.NullableI
                   },
             elementSorter: e => (e.Id1, e.Id2));
 
+    [ConditionalTheory]
+    [MemberData(nameof(IsAsyncData))]
+    public virtual Task Join_uses_csharp_semantics_for_anon_objects(bool async)
+        => AssertQuery(
+            async,
+            ss => from e1 in ss.Set<NullSemanticsEntity1>()
+                  join e2 in ss.Set<NullSemanticsEntity2>() on
+                    new { NullInt = e1.NullableIntA } equals new { NullInt = e2.NullableIntB }
+                  select new
+                  {
+                      Id1 = e1.Id,
+                      Id2 = e2.Id,
+                      e1.NullableIntA,
+                      e2.NullableIntB
+                  },
+            elementSorter: e => (e.Id1, e.Id2));
+
     [ConditionalTheory]
     [MemberData(nameof(IsAsyncData))]
     public virtual Task Contains_with_local_array_closure_with_null(bool async)

test/EFCore.Specification.Tests/Query/ComplexNavigationsQueryTestBase.cs

@@ -3445,6 +3445,22 @@ public virtual Task Composite_key_join_on_groupby_aggregate_projecting_only_grou
                     },
                     (o, i) => i.Key));
 
+    [ConditionalTheory]
+    [MemberData(nameof(IsAsyncData))]
+    public virtual Task Composite_key_join_on_groupby_aggregate_projecting_only_grouping_key2(bool async)
+        => AssertQueryScalar(
+            async,
+            ss => ss.Set<Level1>()
+                .Join(
+                    ss.Set<Level2>().GroupBy(g => g.Id % 3).Select(g => new { g.Key, Sum = g.Sum(x => x.Id) }),
+                    o => new { o.Id, Condition = false },
+                    i => new
+                    {
+                        Id = i.Key,
+                        Condition = i.Sum <= 10,
+                    },
+                    (o, i) => i.Key));
+
     [ConditionalTheory]
     [MemberData(nameof(IsAsyncData))]
     public virtual Task Multiple_joins_groupby_predicate(bool async)

test/EFCore.SqlServer.FunctionalTests/Query/ComplexNavigationsQuerySqlServerTest.cs

@@ -4107,8 +4107,27 @@ INNER JOIN (
         FROM [LevelTwo] AS [l0]
     ) AS [l1]
     GROUP BY [l1].[Key]
-) AS [l2] ON [l].[Id] = [l2].[Key] AND CAST(1 AS bit) = CASE
-    WHEN [l2].[Sum] > 10 THEN CAST(1 AS bit)
+) AS [l2] ON [l].[Id] = [l2].[Key] AND [l2].[Sum] > 10
+""");
+    }
+
+    public override async Task Composite_key_join_on_groupby_aggregate_projecting_only_grouping_key2(bool async)
+    {
+        await base.Composite_key_join_on_groupby_aggregate_projecting_only_grouping_key2(async);
+
+        AssertSql(
+            """
+SELECT [l2].[Key]
+FROM [LevelOne] AS [l]
+INNER JOIN (
+    SELECT [l1].[Key], COALESCE(SUM([l1].[Id]), 0) AS [Sum]
+    FROM (
+        SELECT [l0].[Id], [l0].[Id] % 3 AS [Key]
+        FROM [LevelTwo] AS [l0]
+    ) AS [l1]
+    GROUP BY [l1].[Key]
+) AS [l2] ON [l].[Id] = [l2].[Key] AND CAST(0 AS bit) = CASE
+    WHEN [l2].[Sum] <= 10 THEN CAST(1 AS bit)
     ELSE CAST(0 AS bit)
 END
 """);

test/EFCore.SqlServer.FunctionalTests/Query/ComplexNavigationsSharedTypeQuerySqlServerTest.cs

@@ -920,8 +920,62 @@ WHEN [l2].[OneToOne_Required_PK_Date] IS NOT NULL AND [l2].[Level1_Required_Id]
         WHERE [l2].[OneToOne_Required_PK_Date] IS NOT NULL AND [l2].[Level1_Required_Id] IS NOT NULL AND [l2].[OneToMany_Required_Inverse2Id] IS NOT NULL
     ) AS [s]
     GROUP BY [s].[Key]
-) AS [s1] ON [l].[Id] = [s1].[Key] AND CAST(1 AS bit) = CASE
-    WHEN [s1].[Sum] > 10 THEN CAST(1 AS bit)
+) AS [s1] ON [l].[Id] = [s1].[Key] AND [s1].[Sum] > 10
+""");
+    }
+
+    public override async Task Composite_key_join_on_groupby_aggregate_projecting_only_grouping_key2(bool async)
+    {
+        await base.Composite_key_join_on_groupby_aggregate_projecting_only_grouping_key2(async);
+
+        AssertSql(
+            """
+SELECT [s1].[Key]
+FROM [Level1] AS [l]
+INNER JOIN (
+    SELECT [s].[Key], (
+        SELECT COALESCE(SUM(CASE
+            WHEN [l7].[OneToOne_Required_PK_Date] IS NOT NULL AND [l7].[Level1_Required_Id] IS NOT NULL AND [l7].[OneToMany_Required_Inverse2Id] IS NOT NULL THEN [l7].[Id]
+        END), 0)
+        FROM (
+            SELECT [l3].[Id], CASE
+                WHEN [l4].[OneToOne_Required_PK_Date] IS NOT NULL AND [l4].[Level1_Required_Id] IS NOT NULL AND [l4].[OneToMany_Required_Inverse2Id] IS NOT NULL THEN [l4].[Id]
+            END % 3 AS [Key]
+            FROM [Level1] AS [l3]
+            LEFT JOIN (
+                SELECT [l5].[Id], [l5].[OneToOne_Required_PK_Date], [l5].[Level1_Required_Id], [l5].[OneToMany_Required_Inverse2Id]
+                FROM [Level1] AS [l5]
+                WHERE [l5].[OneToOne_Required_PK_Date] IS NOT NULL AND [l5].[Level1_Required_Id] IS NOT NULL AND [l5].[OneToMany_Required_Inverse2Id] IS NOT NULL
+            ) AS [l4] ON [l3].[Id] = CASE
+                WHEN [l4].[OneToOne_Required_PK_Date] IS NOT NULL AND [l4].[Level1_Required_Id] IS NOT NULL AND [l4].[OneToMany_Required_Inverse2Id] IS NOT NULL THEN [l4].[Id]
+            END
+            WHERE [l4].[OneToOne_Required_PK_Date] IS NOT NULL AND [l4].[Level1_Required_Id] IS NOT NULL AND [l4].[OneToMany_Required_Inverse2Id] IS NOT NULL
+        ) AS [s0]
+        LEFT JOIN (
+            SELECT [l6].[Id], [l6].[OneToOne_Required_PK_Date], [l6].[Level1_Required_Id], [l6].[OneToMany_Required_Inverse2Id]
+            FROM [Level1] AS [l6]
+            WHERE [l6].[OneToOne_Required_PK_Date] IS NOT NULL AND [l6].[Level1_Required_Id] IS NOT NULL AND [l6].[OneToMany_Required_Inverse2Id] IS NOT NULL
+        ) AS [l7] ON [s0].[Id] = CASE
+            WHEN [l7].[OneToOne_Required_PK_Date] IS NOT NULL AND [l7].[Level1_Required_Id] IS NOT NULL AND [l7].[OneToMany_Required_Inverse2Id] IS NOT NULL THEN [l7].[Id]
+        END
+        WHERE [s].[Key] = [s0].[Key] OR ([s].[Key] IS NULL AND [s0].[Key] IS NULL)) AS [Sum]
+    FROM (
+        SELECT CASE
+            WHEN [l2].[OneToOne_Required_PK_Date] IS NOT NULL AND [l2].[Level1_Required_Id] IS NOT NULL AND [l2].[OneToMany_Required_Inverse2Id] IS NOT NULL THEN [l2].[Id]
+        END % 3 AS [Key]
+        FROM [Level1] AS [l0]
+        LEFT JOIN (
+            SELECT [l1].[Id], [l1].[OneToOne_Required_PK_Date], [l1].[Level1_Required_Id], [l1].[OneToMany_Required_Inverse2Id]
+            FROM [Level1] AS [l1]
+            WHERE [l1].[OneToOne_Required_PK_Date] IS NOT NULL AND [l1].[Level1_Required_Id] IS NOT NULL AND [l1].[OneToMany_Required_Inverse2Id] IS NOT NULL
+        ) AS [l2] ON [l0].[Id] = CASE
+            WHEN [l2].[OneToOne_Required_PK_Date] IS NOT NULL AND [l2].[Level1_Required_Id] IS NOT NULL AND [l2].[OneToMany_Required_Inverse2Id] IS NOT NULL THEN [l2].[Id]
+        END
+        WHERE [l2].[OneToOne_Required_PK_Date] IS NOT NULL AND [l2].[Level1_Required_Id] IS NOT NULL AND [l2].[OneToMany_Required_Inverse2Id] IS NOT NULL
+    ) AS [s]
+    GROUP BY [s].[Key]
+) AS [s1] ON [l].[Id] = [s1].[Key] AND CAST(0 AS bit) = CASE
+    WHEN [s1].[Sum] <= 10 THEN CAST(1 AS bit)
     ELSE CAST(0 AS bit)
 END
 """);

test/EFCore.SqlServer.FunctionalTests/Query/GearsOfWarQuerySqlServerTest.cs

@@ -945,7 +945,7 @@ public override async Task Null_propagation_optimization1(bool async)
             """
 SELECT [g].[Nickname], [g].[SquadId], [g].[AssignedCityName], [g].[CityOfBirthName], [g].[Discriminator], [g].[FullName], [g].[HasSoulPatch], [g].[LeaderNickname], [g].[LeaderSquadId], [g].[Rank]
 FROM [Gears] AS [g]
-WHERE [g].[LeaderNickname] = N'Marcus' AND [g].[LeaderNickname] IS NOT NULL
+WHERE [g].[LeaderNickname] = N'Marcus'
 """);
     }
 
@@ -999,10 +999,7 @@ FROM [Gears] AS [g]
 WHERE CASE
     WHEN [g].[LeaderNickname] IS NULL THEN NULL
     ELSE CAST(LEN([g].[LeaderNickname]) AS int)
-END = 5 AND CASE
-    WHEN [g].[LeaderNickname] IS NULL THEN NULL
-    ELSE CAST(LEN([g].[LeaderNickname]) AS int)
-END IS NOT NULL
+END = 5
 """);
     }
 
@@ -1018,10 +1015,7 @@ FROM [Gears] AS [g]
 WHERE CASE
     WHEN [g].[LeaderNickname] IS NOT NULL THEN CAST(LEN([g].[LeaderNickname]) AS int)
     ELSE NULL
-END = 5 AND CASE
-    WHEN [g].[LeaderNickname] IS NOT NULL THEN CAST(LEN([g].[LeaderNickname]) AS int)
-    ELSE NULL
-END IS NOT NULL
+END = 5
 """);
     }
 
@@ -1037,10 +1031,7 @@ FROM [Gears] AS [g]
 WHERE CASE
     WHEN [g].[LeaderNickname] IS NOT NULL THEN CAST(LEN([g].[LeaderNickname]) AS int)
     ELSE NULL
-END = 5 AND CASE
-    WHEN [g].[LeaderNickname] IS NOT NULL THEN CAST(LEN([g].[LeaderNickname]) AS int)
-    ELSE NULL
-END IS NOT NULL
+END = 5
 """);
     }
 

test/EFCore.SqlServer.FunctionalTests/Query/NullSemanticsQuerySqlServerTest.cs

@@ -906,6 +906,18 @@ FROM [Entities1] AS [e]
 """);
     }
 
+    public override async Task Join_uses_csharp_semantics_for_anon_objects(bool async)
+    {
+        await base.Join_uses_csharp_semantics_for_anon_objects(async);
+
+        AssertSql(
+            """
+SELECT [e].[Id] AS [Id1], [e0].[Id] AS [Id2], [e].[NullableIntA], [e0].[NullableIntB]
+FROM [Entities1] AS [e]
+INNER JOIN [Entities2] AS [e0] ON [e].[NullableIntA] = [e0].[NullableIntB] OR ([e].[NullableIntA] IS NULL AND [e0].[NullableIntB] IS NULL)
+""");
+    }
+
     public override async Task Contains_with_local_array_closure_with_null(bool async)
     {
         await base.Contains_with_local_array_closure_with_null(async);

test/EFCore.SqlServer.FunctionalTests/Query/TPCGearsOfWarQuerySqlServerTest.cs

@@ -1319,7 +1319,7 @@ UNION ALL
     SELECT [o].[Nickname], [o].[SquadId], [o].[AssignedCityName], [o].[CityOfBirthName], [o].[FullName], [o].[HasSoulPatch], [o].[LeaderNickname], [o].[LeaderSquadId], [o].[Rank], N'Officer' AS [Discriminator]
     FROM [Officers] AS [o]
 ) AS [u]
-WHERE [u].[LeaderNickname] = N'Marcus' AND [u].[LeaderNickname] IS NOT NULL
+WHERE [u].[LeaderNickname] = N'Marcus'
 """);
     }
 
@@ -1391,10 +1391,7 @@ FROM [Officers] AS [o]
 WHERE CASE
     WHEN [u].[LeaderNickname] IS NULL THEN NULL
     ELSE CAST(LEN([u].[LeaderNickname]) AS int)
-END = 5 AND CASE
-    WHEN [u].[LeaderNickname] IS NULL THEN NULL
-    ELSE CAST(LEN([u].[LeaderNickname]) AS int)
-END IS NOT NULL
+END = 5
 """);
     }
 
@@ -1416,10 +1413,7 @@ FROM [Officers] AS [o]
 WHERE CASE
     WHEN [u].[LeaderNickname] IS NOT NULL THEN CAST(LEN([u].[LeaderNickname]) AS int)
     ELSE NULL
-END = 5 AND CASE
-    WHEN [u].[LeaderNickname] IS NOT NULL THEN CAST(LEN([u].[LeaderNickname]) AS int)
-    ELSE NULL
-END IS NOT NULL
+END = 5
 """);
     }
 
@@ -1441,10 +1435,7 @@ FROM [Officers] AS [o]
 WHERE CASE
     WHEN [u].[LeaderNickname] IS NOT NULL THEN CAST(LEN([u].[LeaderNickname]) AS int)
     ELSE NULL
-END = 5 AND CASE
-    WHEN [u].[LeaderNickname] IS NOT NULL THEN CAST(LEN([u].[LeaderNickname]) AS int)
-    ELSE NULL
-END IS NOT NULL
+END = 5
 """);
     }
 

test/EFCore.SqlServer.FunctionalTests/Query/TPTGearsOfWarQuerySqlServerTest.cs

@@ -1148,7 +1148,7 @@ WHEN [o].[Nickname] IS NOT NULL THEN N'Officer'
 END AS [Discriminator]
 FROM [Gears] AS [g]
 LEFT JOIN [Officers] AS [o] ON [g].[Nickname] = [o].[Nickname] AND [g].[SquadId] = [o].[SquadId]
-WHERE [g].[LeaderNickname] = N'Marcus' AND [g].[LeaderNickname] IS NOT NULL
+WHERE [g].[LeaderNickname] = N'Marcus'
 """);
     }
 
@@ -1211,10 +1211,7 @@ FROM [Gears] AS [g]
 WHERE CASE
     WHEN [g].[LeaderNickname] IS NULL THEN NULL
     ELSE CAST(LEN([g].[LeaderNickname]) AS int)
-END = 5 AND CASE
-    WHEN [g].[LeaderNickname] IS NULL THEN NULL
-    ELSE CAST(LEN([g].[LeaderNickname]) AS int)
-END IS NOT NULL
+END = 5
 """);
     }
 
@@ -1233,10 +1230,7 @@ FROM [Gears] AS [g]
 WHERE CASE
     WHEN [g].[LeaderNickname] IS NOT NULL THEN CAST(LEN([g].[LeaderNickname]) AS int)
     ELSE NULL
-END = 5 AND CASE
-    WHEN [g].[LeaderNickname] IS NOT NULL THEN CAST(LEN([g].[LeaderNickname]) AS int)
-    ELSE NULL
-END IS NOT NULL
+END = 5
 """);
     }
 
@@ -1255,10 +1249,7 @@ FROM [Gears] AS [g]
 WHERE CASE
     WHEN [g].[LeaderNickname] IS NOT NULL THEN CAST(LEN([g].[LeaderNickname]) AS int)
     ELSE NULL
-END = 5 AND CASE
-    WHEN [g].[LeaderNickname] IS NOT NULL THEN CAST(LEN([g].[LeaderNickname]) AS int)
-    ELSE NULL
-END IS NOT NULL
+END = 5
 """);
     }
 

test/EFCore.SqlServer.FunctionalTests/Query/TemporalGearsOfWarQuerySqlServerTest.cs

@@ -1187,7 +1187,7 @@ public override async Task Null_propagation_optimization1(bool async)
             """
 SELECT [g].[Nickname], [g].[SquadId], [g].[AssignedCityName], [g].[CityOfBirthName], [g].[Discriminator], [g].[FullName], [g].[HasSoulPatch], [g].[LeaderNickname], [g].[LeaderSquadId], [g].[PeriodEnd], [g].[PeriodStart], [g].[Rank]
 FROM [Gears] FOR SYSTEM_TIME AS OF '2010-01-01T00:00:00.0000000' AS [g]
-WHERE [g].[LeaderNickname] = N'Marcus' AND [g].[LeaderNickname] IS NOT NULL
+WHERE [g].[LeaderNickname] = N'Marcus'
 """);
     }
 
@@ -1605,10 +1605,7 @@ public override async Task Null_propagation_optimization6(bool async)
 WHERE CASE
     WHEN [g].[LeaderNickname] IS NOT NULL THEN CAST(LEN([g].[LeaderNickname]) AS int)
     ELSE NULL
-END = 5 AND CASE
-    WHEN [g].[LeaderNickname] IS NOT NULL THEN CAST(LEN([g].[LeaderNickname]) AS int)
-    ELSE NULL
-END IS NOT NULL
+END = 5
 """);
     }
 
@@ -4039,10 +4036,7 @@ public override async Task Null_propagation_optimization5(bool async)
 WHERE CASE
     WHEN [g].[LeaderNickname] IS NOT NULL THEN CAST(LEN([g].[LeaderNickname]) AS int)
     ELSE NULL
-END = 5 AND CASE
-    WHEN [g].[LeaderNickname] IS NOT NULL THEN CAST(LEN([g].[LeaderNickname]) AS int)
-    ELSE NULL
-END IS NOT NULL
+END = 5
 """);
     }
 
@@ -4971,10 +4965,7 @@ public override async Task Null_propagation_optimization4(bool async)
 WHERE CASE
     WHEN [g].[LeaderNickname] IS NULL THEN NULL
     ELSE CAST(LEN([g].[LeaderNickname]) AS int)
-END = 5 AND CASE
-    WHEN [g].[LeaderNickname] IS NULL THEN NULL
-    ELSE CAST(LEN([g].[LeaderNickname]) AS int)
-END IS NOT NULL
+END = 5
 """);
     }