Normalize .Count != 0 to Any() in preprocessing

Closes #33644
dotnet · May 1, 2024 · bd44c94 · bd44c94
1 parent ebbc5ee
commit bd44c94
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Showing 2 changed files with 41 additions and 17 deletions.
diff --git a/src/EFCore/Query/Internal/QueryableMethodNormalizingExpressionVisitor.cs b/src/EFCore/Query/Internal/QueryableMethodNormalizingExpressionVisitor.cs
@@ -49,23 +49,47 @@ public virtual Expression Normalize(Expression expression)
     ///     any release. You should only use it directly in your code with extreme caution and knowing that
     ///     doing so can result in application failures when updating to a new Entity Framework Core release.
     /// </summary>
-    protected override Expression VisitBinary(BinaryExpression binaryExpression)
-    {
-        // Convert array[x] to array.ElementAt(x)
-        if (binaryExpression is
-            {
-                NodeType: ExpressionType.ArrayIndex,
-                Left: var source,
-                Right: var index
-            })
+    protected override Expression VisitBinary(BinaryExpression binaryExpression) =>
+        binaryExpression switch
         {
-            return VisitMethodCall(
+            // Convert array[x] to array.ElementAt(x)
+            { NodeType: ExpressionType.ArrayIndex, Left: var source, Right: var index }
+                => VisitMethodCall(
+                    Expression.Call(EnumerableMethods.ElementAt.MakeGenericMethod(source.Type.GetSequenceType()), source, index)),
+
+            // Convert x.Count > 0 and x.Count != 0 to x.Any()
+            {
+                NodeType: ExpressionType.GreaterThan or ExpressionType.NotEqual,
+                Left: MemberExpression
+                {
+                    Member: { Name: nameof(ICollection<object>.Count), DeclaringType.IsGenericType: true } member,
+                    Expression: Expression source
+                },
+                Right: ConstantExpression { Value: 0 }
+            }
+            when (member.DeclaringType.GetGenericTypeDefinition().GetInterfaces().Any(x => x.GetGenericTypeDefinition() == typeof(ICollection<>)))
+            => VisitMethodCall(
                 Expression.Call(
-                    EnumerableMethods.ElementAt.MakeGenericMethod(source.Type.GetSequenceType()), source, index));
-        }
+                    EnumerableMethods.AnyWithoutPredicate.MakeGenericMethod(source.Type.GetSequenceType()),
+                    source)),
 
-        return base.VisitBinary(binaryExpression);
-    }
+            // Same for arrays: convert x.Length > 0 and x.Length != 0 to x.Any()
+            {
+                    NodeType: ExpressionType.GreaterThan or ExpressionType.NotEqual,
+                    Left: UnaryExpression
+                    {
+                        NodeType: ExpressionType.ArrayLength,
+                        Operand: Expression source
+                    },
+                    Right: ConstantExpression { Value: 0 }
+                }
+                => VisitMethodCall(
+                    Expression.Call(
+                        EnumerableMethods.AnyWithoutPredicate.MakeGenericMethod(source.Type.GetSequenceType()),
+                        source)),
+
+            _ => base.VisitBinary(binaryExpression)
+        };
 
     /// <summary>
     ///     This is an internal API that supports the Entity Framework Core infrastructure and not subject to

diff --git a/test/EFCore.SqlServer.FunctionalTests/Query/NorthwindNavigationsQuerySqlServerTest.cs b/test/EFCore.SqlServer.FunctionalTests/Query/NorthwindNavigationsQuerySqlServerTest.cs
@@ -526,10 +526,10 @@ public override async Task Collection_select_nav_prop_predicate(bool async)
         AssertSql(
             """
 SELECT CASE
-    WHEN (
-        SELECT COUNT(*)
+    WHEN EXISTS (
+        SELECT 1
         FROM [Orders] AS [o]
-        WHERE [c].[CustomerID] = [o].[CustomerID]) > 0 THEN CAST(1 AS bit)
+        WHERE [c].[CustomerID] = [o].[CustomerID]) THEN CAST(1 AS bit)
     ELSE CAST(0 AS bit)
 END
 FROM [Customers] AS [c]