Modify test to avoid simplification

Author: roji

Diff for: src/EFCore.Cosmos/Query/Internal/SqlExpressionFactory.cs

@@ -685,10 +685,37 @@ public virtual SqlExpression Condition(SqlExpression test, SqlExpression ifTrue,
     {
         var typeMapping = ExpressionExtensions.InferTypeMapping(ifTrue, ifFalse);
 
-        return new SqlConditionalExpression(
-            ApplyTypeMapping(test, _boolTypeMapping),
-            ApplyTypeMapping(ifTrue, typeMapping),
-            ApplyTypeMapping(ifFalse, typeMapping));
+        test = ApplyTypeMapping(test, _boolTypeMapping);
+        ifTrue = ApplyTypeMapping(ifTrue, typeMapping);
+        ifFalse = ApplyTypeMapping(ifFalse, typeMapping);
+
+        // Simplify:
+        // a == b ? b : a -> a
+        // a != b ? a : b -> a
+        if (test is SqlBinaryExpression
+            {
+                OperatorType: ExpressionType.Equal or ExpressionType.NotEqual,
+                Left: var left,
+                Right: var right
+            } binary)
+        {
+            // Reverse ifEqual/ifNotEqual for ExpressionType.NotEqual for easier reasoning below
+            var (ifEqual, ifNotEqual) = binary.OperatorType is ExpressionType.Equal ? (ifTrue, ifFalse) : (ifFalse, ifTrue);
+
+            // a == b ? b : a -> a
+            if (left.Equals(ifNotEqual) && right.Equals(ifEqual))
+            {
+                return left;
+            }
+
+            // b == a ? b : a -> a
+            if (right.Equals(ifNotEqual) && left.Equals(ifEqual))
+            {
+                return right;
+            }
+        }
+
+        return new SqlConditionalExpression(test, ifTrue, ifFalse);
     }
 
     /// <summary>

Diff for: src/EFCore.Relational/Query/SqlExpressionFactory.cs

@@ -835,13 +835,16 @@ public virtual SqlExpression Case(
             && typeMappedWhenClauses is
             [
                 {
-                    Test: SqlBinaryExpression { OperatorType: ExpressionType.Equal or ExpressionType.NotEqual } binary,
+                    Test: SqlBinaryExpression
+                    {
+                        OperatorType: ExpressionType.Equal or ExpressionType.NotEqual,
+                        Left: var left,
+                        Right: var right
+                    } binary,
                     Result: var result
                 }
             ])
         {
-            var (left, right) = (binary.Left, binary.Right);
-
             // Reverse ifEqual/ifNotEqual for ExpressionType.NotEqual for easier reasoning below
             var (ifEqual, ifNotEqual) = binary.OperatorType is ExpressionType.Equal
                 ? (result, elseResult ?? Constant(null, result.Type, result.TypeMapping))

Diff for: test/EFCore.Cosmos.FunctionalTests/Query/Translations/OperatorTranslationsCosmosTest.cs

@@ -19,12 +19,11 @@ public override Task Conditional_simplifiable_equality(bool async)
             {
                 await base.Conditional_simplifiable_equality(a);
 
-                // TODO: Simplify this away, as per #35327 for relational
                 AssertSql(
                     """
 SELECT VALUE c
 FROM root c
-WHERE (((c["Int"] = 9) ? 9 : c["Int"]) > 1)
+WHERE (c["Int"] > 1)
 """);
             });
 
@@ -34,12 +33,11 @@ public override Task Conditional_simplifiable_inequality(bool async)
             {
                 await base.Conditional_simplifiable_inequality(a);
 
-                // TODO: Simplify this away, as per #35327 for relational
                 AssertSql(
                     """
 SELECT VALUE c
 FROM root c
-WHERE (((c["Int"] != 8) ? c["Int"] : 8) > 1)
+WHERE (c["Int"] > 1)
 """);
             });
 

Diff for: test/EFCore.Relational.Specification.Tests/Query/NullSemanticsQueryTestBase.cs

@@ -753,7 +753,7 @@ public virtual Task Where_equal_with_conditional(bool async)
             ss => ss.Set<NullSemanticsEntity1>().Where(
                 e => (e.NullableStringA == e.NullableStringB
                         ? e.NullableStringA
-                        : e.NullableStringB)
+                        : e.NullableStringC)
                     == e.NullableStringC).Select(e => e.Id));
 
     [ConditionalTheory]
@@ -765,7 +765,7 @@ public virtual Task Where_not_equal_with_conditional(bool async)
                 e => e.NullableStringC
                     != (e.NullableStringA == e.NullableStringB
                         ? e.NullableStringA
-                        : e.NullableStringB)).Select(e => e.Id));
+                        : e.NullableStringC)).Select(e => e.Id));
 
     [ConditionalTheory]
     [MemberData(nameof(IsAsyncData))]

Diff for: test/EFCore.SqlServer.FunctionalTests/Query/NullSemanticsQuerySqlServerTest.cs

@@ -2205,7 +2205,13 @@ public override async Task Where_equal_with_conditional(bool async)
             """
 SELECT [e].[Id]
 FROM [Entities1] AS [e]
-WHERE [e].[NullableStringB] = [e].[NullableStringC] OR ([e].[NullableStringB] IS NULL AND [e].[NullableStringC] IS NULL)
+WHERE CASE
+    WHEN [e].[NullableStringA] = [e].[NullableStringB] OR ([e].[NullableStringA] IS NULL AND [e].[NullableStringB] IS NULL) THEN [e].[NullableStringA]
+    ELSE [e].[NullableStringC]
+END = [e].[NullableStringC] OR (CASE
+    WHEN [e].[NullableStringA] = [e].[NullableStringB] OR ([e].[NullableStringA] IS NULL AND [e].[NullableStringB] IS NULL) THEN [e].[NullableStringA]
+    ELSE [e].[NullableStringC]
+END IS NULL AND [e].[NullableStringC] IS NULL)
 """);
     }
 
@@ -2217,7 +2223,16 @@ public override async Task Where_not_equal_with_conditional(bool async)
             """
 SELECT [e].[Id]
 FROM [Entities1] AS [e]
-WHERE ([e].[NullableStringC] <> [e].[NullableStringB] OR [e].[NullableStringC] IS NULL OR [e].[NullableStringB] IS NULL) AND ([e].[NullableStringC] IS NOT NULL OR [e].[NullableStringB] IS NOT NULL)
+WHERE ([e].[NullableStringC] <> CASE
+    WHEN [e].[NullableStringA] = [e].[NullableStringB] OR ([e].[NullableStringA] IS NULL AND [e].[NullableStringB] IS NULL) THEN [e].[NullableStringA]
+    ELSE [e].[NullableStringC]
+END OR [e].[NullableStringC] IS NULL OR CASE
+    WHEN [e].[NullableStringA] = [e].[NullableStringB] OR ([e].[NullableStringA] IS NULL AND [e].[NullableStringB] IS NULL) THEN [e].[NullableStringA]
+    ELSE [e].[NullableStringC]
+END IS NULL) AND ([e].[NullableStringC] IS NOT NULL OR CASE
+    WHEN [e].[NullableStringA] = [e].[NullableStringB] OR ([e].[NullableStringA] IS NULL AND [e].[NullableStringB] IS NULL) THEN [e].[NullableStringA]
+    ELSE [e].[NullableStringC]
+END IS NOT NULL)
 """);
     }