[GA] Ensure case-insensitive parameter name uniqueness

src/EFCore.Relational/Query/Internal/RelationalParameterProcessor.cs

@@ -31,7 +31,7 @@ private readonly IDictionary<FromSqlExpression, Expression> _visitedFromSqlExpre
     ///     <see cref="ISqlGenerationHelper.GenerateParameterName(string)" /> (i.e. they're prefixed), since
     ///     <see cref="DbParameter.ParameterName" /> can be prefixed or not.
     /// </summary>
-    private readonly HashSet<string> _prefixedParameterNames = [];
+    private readonly HashSet<string> _prefixedParameterNames = new(StringComparer.OrdinalIgnoreCase);
 
     private readonly Dictionary<string, SqlParameterExpression> _sqlParameters = new();
 

test/EFCore.Cosmos.FunctionalTests/Query/NorthwindWhereQueryCosmosTest.cs

@@ -1529,13 +1529,39 @@ public override async Task Using_same_parameter_twice_in_query_generates_one_sql
         AssertSql();
     }
 
-    public override async Task Two_parameters_with_same_name_get_uniquified(bool async)
-    {
-        // Concat with conversion, issue #34963.
-        await AssertTranslationFailed(() => base.Using_same_parameter_twice_in_query_generates_one_sql_parameter(async));
+    public override Task Two_parameters_with_same_name_get_uniquified(bool async)
+        => Fixture.NoSyncTest(
+            async, async a =>
+            {
+                await base.Two_parameters_with_same_name_get_uniquified(async);
 
-        AssertSql();
-    }
+                AssertSql(
+                    """
+@customerId='ANATR'
+@customerId0='ALFKI'
+
+SELECT VALUE c
+FROM root c
+WHERE ((c["id"] = @customerId) OR (c["id"] = @customerId0))
+""");
+            });
+
+    public override Task Two_parameters_with_same_case_insensitive_name_get_uniquified(bool async)
+        => Fixture.NoSyncTest(
+            async, async a =>
+            {
+                await base.Two_parameters_with_same_case_insensitive_name_get_uniquified(async);
+
+                AssertSql(
+                    """
+@customerID='ANATR'
+@customerId='ALFKI'
+
+SELECT VALUE c
+FROM root c
+WHERE ((c["id"] = @customerID) OR (c["id"] = @customerId))
+""");
+            });
 
     public override async Task Where_Queryable_ToList_Count(bool async)
     {

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

@@ -1327,16 +1327,27 @@ public virtual Task Using_same_parameter_twice_in_query_generates_one_sql_parame
                 .Select(c => c.CustomerID));
     }
 
+    private readonly string customerId = "ALFKI";
+
     [ConditionalTheory, MemberData(nameof(IsAsyncData))]
     public virtual Task Two_parameters_with_same_name_get_uniquified(bool async)
     {
-        var i = 10;
+        var customerId = "ANATR";
+
+        return AssertQuery(
+            async,
+            ss => ss.Set<Customer>().Where(c => c.CustomerID == customerId || c.CustomerID == this.customerId));
+    }
+
+    [ConditionalTheory, MemberData(nameof(IsAsyncData))]
+    public virtual Task Two_parameters_with_same_case_insensitive_name_get_uniquified(bool async)
+    {
+        var customerID = "ANATR";
 
-        // i+1 and i+2 each get parameterized using the same parameter name (since they're complex expressions).
-        // This exercises that query parameters are properly uniquified.
+        // Note the parameter names differ only by case (customerID vs. customerId)
         return AssertQuery(
             async,
-            ss => ss.Set<Customer>().Where(c => (c.CustomerID + (i + 1)) + (c.CustomerID + (i + 2)) == "ALFKI11ALFKI12"));
+            ss => ss.Set<Customer>().Where(c => c.CustomerID == customerID || c.CustomerID == customerId));
     }
 
     [ConditionalTheory, MemberData(nameof(IsAsyncData))]

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

@@ -1704,19 +1704,33 @@ WHERE CAST(@i AS nvarchar(max)) + [c].[CustomerID] + CAST(@i AS nvarchar(max)) =
 """);
     }
 
-    [ConditionalTheory]
     public override async Task Two_parameters_with_same_name_get_uniquified(bool async)
     {
         await base.Two_parameters_with_same_name_get_uniquified(async);
 
         AssertSql(
             """
-@p='11'
-@p0='12'
+@customerId='ANATR' (Size = 5) (DbType = StringFixedLength)
+@customerId0='ALFKI' (Size = 5) (DbType = StringFixedLength)
+
+SELECT [c].[CustomerID], [c].[Address], [c].[City], [c].[CompanyName], [c].[ContactName], [c].[ContactTitle], [c].[Country], [c].[Fax], [c].[Phone], [c].[PostalCode], [c].[Region]
+FROM [Customers] AS [c]
+WHERE [c].[CustomerID] = @customerId OR [c].[CustomerID] = @customerId0
+""");
+    }
+
+    public override async Task Two_parameters_with_same_case_insensitive_name_get_uniquified(bool async)
+    {
+        await base.Two_parameters_with_same_case_insensitive_name_get_uniquified(async);
+
+AssertSql(
+"""
+@customerID='ANATR' (Size = 5) (DbType = StringFixedLength)
+@customerId0='ALFKI' (Size = 5) (DbType = StringFixedLength)
 
 SELECT [c].[CustomerID], [c].[Address], [c].[City], [c].[CompanyName], [c].[ContactName], [c].[ContactTitle], [c].[Country], [c].[Fax], [c].[Phone], [c].[PostalCode], [c].[Region]
 FROM [Customers] AS [c]
-WHERE [c].[CustomerID] + CAST(@p AS nvarchar(max)) + [c].[CustomerID] + CAST(@p0 AS nvarchar(max)) = N'ALFKI11ALFKI12'
+WHERE [c].[CustomerID] = @customerID OR [c].[CustomerID] = @customerId0
 """);
     }