Fix/suppress new code style warnings.

These were detected by either .NET 9 Preview 3 SDK or Visual Studio 2022 v17.10 Preview 3.

Author: bgrainger

.editorconfig

@@ -16,13 +16,16 @@ indent_style = tab
 indent_size = 4
 
 # changes from VS2017 defaults
+csharp_style_expression_bodied_local_functions = true:suggestion
 csharp_style_expression_bodied_methods = true:suggestion
 csharp_style_expression_bodied_constructors = true:suggestion
 csharp_style_expression_bodied_operators = true:suggestion
+csharp_style_namespace_declarations = file_scoped
 csharp_prefer_braces = false:none
 csharp_indent_switch_labels = true
 csharp_space_after_cast = true
 csharp_preserve_single_line_statements = false
+dotnet_style_prefer_conditional_expression_over_return = false:suggestion
 
 # use VS2017 defaults, but make them warnings (instead of none)
 dotnet_style_qualification_for_field = false:warning
@@ -84,7 +87,11 @@ dotnet_diagnostic.CA2100.severity = none # Review SQL queries for security vulne
 dotnet_diagnostic.CA2213.severity = silent # Disposable fields should be disposed.
 dotnet_diagnostic.CA5398.severity = none # Avoid hardcoded SslProtocols values.
 dotnet_diagnostic.IDE0044.severity = error # Make fields readonly.
+dotnet_diagnostic.IDE0045.severity = suggestion # Use conditional expression for assignment.
+dotnet_diagnostic.IDE0058.severity = none # Remove unnecessary expression value.
+dotnet_diagnostic.IDE0059.severity = none # Remove unnecessary value assignment.
 dotnet_diagnostic.IDE0065.severity = error # Using directives must be placed outside of a namespace declaration.
+dotnet_diagnostic.IDE0072.severity = silent # Add missing cases to switch expression.
 dotnet_diagnostic.SA1003.severity = none # Operator must not be followed by whitespace.
 dotnet_diagnostic.SA1008.severity = none # Opening parenthesis must not be preceded by a space.
 dotnet_diagnostic.SA1009.severity = none # Closing parenthesis must not be followed by a space.

src/MySqlConnector/ColumnReaders/BinaryDateTimeColumnReader.cs

@@ -47,7 +47,7 @@ public override object ReadValue(ReadOnlySpan<byte> data, ColumnDefinitionPayloa
 
 		try
 		{
-			return m_allowZeroDateTime ? (object) new MySqlDateTime(year, month, day, hour, minute, second, microseconds) :
+			return m_allowZeroDateTime ? new MySqlDateTime(year, month, day, hour, minute, second, microseconds) :
 #if NET7_0_OR_GREATER
 				new DateTime(year, month, day, hour, minute, second, microseconds / 1000, microseconds % 1000, m_dateTimeKind);
 #else

src/MySqlConnector/ColumnReaders/GuidBinary16ColumnReader.cs

@@ -20,6 +20,6 @@ public static Guid ReadGuid(ReadOnlySpan<byte> data) =>
 #elif NETCOREAPP2_1_OR_GREATER || NETSTANDARD2_1_OR_GREATER
 		new(stackalloc byte[16] { data[3], data[2], data[1], data[0], data[5], data[4], data[7], data[6], data[8], data[9], data[10], data[11], data[12], data[13], data[14], data[15] });
 #else
-		new(new[] { data[3], data[2], data[1], data[0], data[5], data[4], data[7], data[6], data[8], data[9], data[10], data[11], data[12], data[13], data[14], data[15] });
+		new([data[3], data[2], data[1], data[0], data[5], data[4], data[7], data[6], data[8], data[9], data[10], data[11], data[12], data[13], data[14], data[15]]);
 #endif
 }

src/MySqlConnector/ColumnReaders/GuidTimeSwapBinary16ColumnReader.cs

@@ -18,6 +18,6 @@ public static Guid ReadGuid(ReadOnlySpan<byte> data) =>
 #if NETCOREAPP2_1_OR_GREATER || NETSTANDARD2_1_OR_GREATER
 		new(stackalloc byte[16] { data[7], data[6], data[5], data[4], data[3], data[2], data[1], data[0], data[8], data[9], data[10], data[11], data[12], data[13], data[14], data[15] });
 #else
-		new(new[] { data[7], data[6], data[5], data[4], data[3], data[2], data[1], data[0], data[8], data[9], data[10], data[11], data[12], data[13], data[14], data[15] });
+		new([data[7], data[6], data[5], data[4], data[3], data[2], data[1], data[0], data[8], data[9], data[10], data[11], data[12], data[13], data[14], data[15]]);
 #endif
 }

src/MySqlConnector/Core/CachedProcedure.cs

@@ -79,9 +79,9 @@ FROM information_schema.parameters
 			cmd.Parameters.AddWithValue("@component", component);
 
 			using var reader = await cmd.ExecuteReaderNoResetTimeoutAsync(CommandBehavior.Default, ioBehavior, cancellationToken).ConfigureAwait(false);
-			await reader.ReadAsync(ioBehavior, cancellationToken).ConfigureAwait(false);
+			_ = await reader.ReadAsync(ioBehavior, cancellationToken).ConfigureAwait(false);
 			routineCount = reader.GetInt32(0);
-			await reader.NextResultAsync(ioBehavior, cancellationToken).ConfigureAwait(false);
+			_ = await reader.NextResultAsync(ioBehavior, cancellationToken).ConfigureAwait(false);
 
 			while (await reader.ReadAsync(ioBehavior, cancellationToken).ConfigureAwait(false))
 			{
@@ -168,17 +168,17 @@ internal static List<CachedParameter> ParseParameters(string parametersSql)
 			if (parameter.StartsWith("INOUT ", StringComparison.OrdinalIgnoreCase))
 			{
 				direction = "INOUT";
-				parameter = parameter.Substring(6);
+				parameter = parameter[6..];
 			}
 			else if (parameter.StartsWith("OUT ", StringComparison.OrdinalIgnoreCase))
 			{
 				direction = "OUT";
-				parameter = parameter.Substring(4);
+				parameter = parameter[4..];
 			}
 			else if (parameter.StartsWith("IN ", StringComparison.OrdinalIgnoreCase))
 			{
 				direction = "IN";
-				parameter = parameter.Substring(3);
+				parameter = parameter[3..];
 			}
 
 			var parts = s_parameterName.Match(parameter);
@@ -206,7 +206,7 @@ internal static string ParseDataType(string sql, out bool unsigned, out int leng
 		}
 
 		var list = sql.Trim().Split(' ');
-		var type = string.Empty;
+		string? type;
 
 		if (list.Length < 2 || !s_typeMapping.TryGetValue(list[0] + ' ' + list[1], out type))
 		{

src/MySqlConnector/Core/ConnectionPool.cs

@@ -1,8 +1,6 @@
 using System.Collections.Concurrent;
 using System.Diagnostics;
-using System.Diagnostics.Metrics;
 using System.Net;
-using System.Security.Authentication;
 using Microsoft.Extensions.Logging;
 using MySqlConnector.Logging;
 using MySqlConnector.Protocol.Serialization;
@@ -140,7 +138,7 @@ public async ValueTask<ServerSession> GetSessionAsync(MySqlConnection connection
 				}
 			}
 
-			m_sessionSemaphore.Release();
+			_ = m_sessionSemaphore.Release();
 			throw;
 		}
 	}
@@ -172,14 +170,14 @@ public async ValueTask ReturnAsync(IOBehavior ioBehavior, ServerSession session)
 		try
 		{
 			lock (m_leasedSessions)
-				m_leasedSessions.Remove(session.Id);
+				_ = m_leasedSessions.Remove(session.Id);
 			MetricsReporter.RemoveUsed(this);
 			session.OwningConnection = null;
 			var sessionHealth = GetSessionHealth(session);
 			if (sessionHealth == 0)
 			{
 				lock (m_sessions)
-					m_sessions.AddFirst(session);
+					_ = m_sessions.AddFirst(session);
 				MetricsReporter.AddIdle(this);
 			}
 			else
@@ -194,15 +192,15 @@ public async ValueTask ReturnAsync(IOBehavior ioBehavior, ServerSession session)
 		}
 		finally
 		{
-			m_sessionSemaphore.Release();
+			_ = m_sessionSemaphore.Release();
 		}
 	}
 
 	public async Task ClearAsync(IOBehavior ioBehavior, CancellationToken cancellationToken)
 	{
 		// increment the generation of the connection pool
 		Log.ClearingConnectionPool(m_logger, Id);
-		Interlocked.Increment(ref m_generation);
+		_ = Interlocked.Increment(ref m_generation);
 		m_procedureCache = null;
 		await RecoverLeakedSessionsAsync(ioBehavior).ConfigureAwait(false);
 		await CleanPoolAsync(ioBehavior, session => session.PoolGeneration != m_generation, false, cancellationToken).ConfigureAwait(false);
@@ -406,13 +404,13 @@ private async Task CreateMinimumPooledSessions(MySqlConnection connection, IOBeh
 				var session = await ConnectSessionAsync(connection, s_createdToReachMinimumPoolSize, Stopwatch.GetTimestamp(), null, ioBehavior, cancellationToken).ConfigureAwait(false);
 				AdjustHostConnectionCount(session, 1);
 				lock (m_sessions)
-					m_sessions.AddFirst(session);
+					_ = m_sessions.AddFirst(session);
 				MetricsReporter.AddIdle(this);
 			}
 			finally
 			{
 				// connection is in pool; semaphore shouldn't be held any more
-				m_sessionSemaphore.Release();
+				_ = m_sessionSemaphore.Release();
 			}
 		}
 	}
@@ -452,7 +450,7 @@ private async ValueTask<ServerSession> ConnectSessionAsync(MySqlConnection conne
 					var redirectedSession = new ServerSession(m_connectionLogger, this, m_generation, Interlocked.Increment(ref m_lastSessionId));
 					try
 					{
-						await redirectedSession.ConnectAsync(redirectedSettings, connection, startingTimestamp, m_loadBalancer, activity, ioBehavior, cancellationToken).ConfigureAwait(false);
+						_ = await redirectedSession.ConnectAsync(redirectedSettings, connection, startingTimestamp, m_loadBalancer, activity, ioBehavior, cancellationToken).ConfigureAwait(false);
 					}
 					catch (Exception ex)
 					{
@@ -614,7 +612,7 @@ private ConnectionPool(MySqlConnectorLoggingConfiguration loggingConfiguration,
 			cs.HostNames!.Count == 1 || cs.LoadBalance == MySqlLoadBalance.FailOver ? FailOverLoadBalancer.Instance :
 			cs.LoadBalance == MySqlLoadBalance.Random ? RandomLoadBalancer.Instance :
 			cs.LoadBalance == MySqlLoadBalance.LeastConnections ? new LeastConnectionsLoadBalancer(m_hostSessions!) :
-			(ILoadBalancer) new RoundRobinLoadBalancer();
+			 new RoundRobinLoadBalancer();
 
 		// create tag lists for reporting pool metrics
 		var connectionString = cs.ConnectionStringBuilder.GetConnectionString(includePassword: false);
@@ -812,7 +810,7 @@ private static void OnAppDomainShutDown(object? sender, EventArgs e) =>
 		ClearPoolsAsync(IOBehavior.Synchronous, CancellationToken.None).GetAwaiter().GetResult();
 
 	private static readonly ConcurrentDictionary<string, ConnectionPool?> s_pools = new();
-	private static readonly List<ConnectionPool> s_allPools = new();
+	private static readonly List<ConnectionPool> s_allPools = [];
 	private static readonly Action<ILogger, int, string, Exception?> s_createdNewSession = LoggerMessage.Define<int, string>(
 		LogLevel.Debug, new EventId(EventIds.PoolCreatedNewSession, nameof(EventIds.PoolCreatedNewSession)),
 		"Pool {PoolId} has no pooled session available; created new session {SessionId}");

src/MySqlConnector/Core/ConnectionSettings.cs

@@ -1,4 +1,6 @@
+#if NETCOREAPP3_0_OR_GREATER
 using System.Net.Security;
+#endif
 using System.Security.Authentication;
 using MySqlConnector.Utilities;
 
@@ -148,7 +150,7 @@ public ConnectionSettings(MySqlConnectionStringBuilder csb)
 		static int ToSigned(uint value) => value >= int.MaxValue ? int.MaxValue : (int) value;
 	}
 
-	public ConnectionSettings CloneWith(string host, int port, string userId) => new ConnectionSettings(this, host, port, userId);
+	public ConnectionSettings CloneWith(string host, int port, string userId) => new(this, host, port, userId);
 
 	private static MySqlGuidFormat GetEffectiveGuidFormat(MySqlGuidFormat guidFormat, bool oldGuids)
 	{
@@ -326,5 +328,5 @@ private ConnectionSettings(ConnectionSettings other, string host, int port, stri
 		UseXaTransactions = other.UseXaTransactions;
 	}
 
-	private static readonly string[] s_localhostPipeServer = { "." };
+	private static readonly string[] s_localhostPipeServer = ["."];
 }

src/MySqlConnector/Core/EnlistedTransactionBase.cs

@@ -2,18 +2,18 @@
 
 namespace MySqlConnector.Core;
 
-internal abstract class EnlistedTransactionBase : IEnlistmentNotification
+internal abstract class EnlistedTransactionBase(Transaction transaction, MySqlConnection connection) : IEnlistmentNotification
 {
 	// A MySqlConnection that holds the ServerSession that was enrolled in the transaction
-	public MySqlConnection Connection { get; set; }
+	public MySqlConnection Connection { get; set; } = connection;
 
 	// Whether the connection is idle, i.e., a client has closed it and is no longer using it
 	public bool IsIdle { get; set; }
 
 	// Whether the distributed transaction was prepared successfully
 	public bool IsPrepared { get; private set; }
 
-	public Transaction Transaction { get; private set; }
+	public Transaction Transaction { get; private set; } = transaction;
 
 	public void Start()
 	{
@@ -51,12 +51,6 @@ void IEnlistmentNotification.Rollback(Enlistment enlistment)
 
 	public void InDoubt(Enlistment enlistment) => throw new NotImplementedException();
 
-	protected EnlistedTransactionBase(Transaction transaction, MySqlConnection connection)
-	{
-		Transaction = transaction;
-		Connection = connection;
-	}
-
 	protected abstract void OnStart();
 	protected abstract void OnPrepare(PreparingEnlistment enlistment);
 	protected abstract void OnCommit(Enlistment enlistment);

src/MySqlConnector/Core/ILoadBalancer.cs

@@ -35,11 +35,7 @@ public IReadOnlyList<string> LoadBalance(IReadOnlyList<string> hosts)
 			lock (m_random)
 				j = m_random.Next(i + 1);
 			if (i != j)
-			{
-				var temp = shuffled[i];
-				shuffled[i] = shuffled[j];
-				shuffled[j] = temp;
-			}
+				(shuffled[j], shuffled[i]) = (shuffled[i], shuffled[j]);
 		}
 		return shuffled;
 	}

src/MySqlConnector/Core/MetricsReporter.cs

@@ -28,13 +28,13 @@ public static void RemovePendingRequest(ConnectionPool? pool)
 
 	static MetricsReporter()
 	{
-		ActivitySourceHelper.Meter.CreateObservableUpDownCounter<int>("db.client.connections.idle.max",
+		_ = ActivitySourceHelper.Meter.CreateObservableUpDownCounter<int>("db.client.connections.idle.max",
 			observeValues: GetMaximumConnections, unit: "{connection}",
 			description: "The maximum number of idle open connections allowed; this corresponds to MaximumPoolSize in the connection string.");
-		ActivitySourceHelper.Meter.CreateObservableUpDownCounter<int>("db.client.connections.idle.min",
+		_ = ActivitySourceHelper.Meter.CreateObservableUpDownCounter<int>("db.client.connections.idle.min",
 			observeValues: GetMinimumConnections, unit: "{connection}",
 			description: "The minimum number of idle open connections allowed; this corresponds to MinimumPoolSize in the connection string.");
-		ActivitySourceHelper.Meter.CreateObservableUpDownCounter<int>("db.client.connections.max",
+		_ = ActivitySourceHelper.Meter.CreateObservableUpDownCounter<int>("db.client.connections.max",
 			observeValues: GetMaximumConnections, unit: "{connection}",
 			description: "The maximum number of open connections allowed; this corresponds to MaximumPoolSize in the connection string.");
 

src/MySqlConnector/Core/NormalizedSchema.cs

@@ -17,15 +17,13 @@ internal sealed partial class NormalizedSchema
 	private static readonly Regex s_nameRegex = new(ReName, RegexOptions.Compiled);
 #endif
 
-	public static NormalizedSchema MustNormalize(string name, string? defaultSchema = null)
-	{
-		var normalized = new NormalizedSchema(name, defaultSchema);
-		if (normalized.Component is null)
-			throw new ArgumentException("Could not determine function/procedure name", nameof(name));
-		if (normalized.Schema is null)
-			throw new ArgumentException("Could not determine schema", nameof(defaultSchema));
-		return normalized;
-	}
+	public static NormalizedSchema MustNormalize(string name, string? defaultSchema = null) =>
+		new NormalizedSchema(name, defaultSchema) switch
+		{
+			{ Component: null } => throw new ArgumentException("Could not determine function/procedure name", nameof(name)),
+			{ Schema: null } => throw new ArgumentException("Could not determine schema", nameof(defaultSchema)),
+			{ } normalized => normalized,
+		};
 
 	public NormalizedSchema(string name, string? defaultSchema = null)
 	{

src/MySqlConnector/Core/ResultSet.cs

@@ -159,7 +159,7 @@ public async Task ReadResultSetHeaderAsync(IOBehavior ioBehavior)
 					if (!Session.SupportsDeprecateEof)
 					{
 						payload = await Session.ReceiveReplyAsync(ioBehavior, CancellationToken.None).ConfigureAwait(false);
-						EofPayload.Create(payload.Span);
+						_ = EofPayload.Create(payload.Span);
 					}
 
 					if (ColumnDefinitions.Length == (Command?.OutParameters?.Count + 1) && ColumnDefinitions[0].Name == SingleCommandPayloadCreator.OutParameterSentinelColumnName)
@@ -182,16 +182,13 @@ public async Task ReadResultSetHeaderAsync(IOBehavior ioBehavior)
 		}
 	}
 
-	private static bool IsHostVerified(MySqlConnection connection)
-	{
-		return connection.SslMode == MySqlSslMode.VerifyCA
-			|| connection.SslMode == MySqlSslMode.VerifyFull;
-	}
+	private static bool IsHostVerified(MySqlConnection connection) =>
+		connection.SslMode is MySqlSslMode.VerifyCA or MySqlSslMode.VerifyFull;
 
 	public async Task ReadEntireAsync(IOBehavior ioBehavior, CancellationToken cancellationToken)
 	{
 		while (State is ResultSetState.ReadingRows or ResultSetState.ReadResultSetHeader)
-			await ReadAsync(ioBehavior, cancellationToken).ConfigureAwait(false);
+			_ = await ReadAsync(ioBehavior, cancellationToken).ConfigureAwait(false);
 	}
 
 	public bool Read()

src/MySqlConnector/Core/Row.cs

@@ -1,10 +1,11 @@
-using System.Runtime.CompilerServices;
 using System.Runtime.InteropServices;
 using System.Text;
 using MySqlConnector.ColumnReaders;
 using MySqlConnector.Protocol;
 using MySqlConnector.Protocol.Serialization;
+#if !NETCOREAPP2_1_OR_GREATER && !NETSTANDARD2_1_OR_GREATER
 using MySqlConnector.Utilities;
+#endif
 
 namespace MySqlConnector.Core;
 
@@ -30,7 +31,7 @@ public void SetData(ReadOnlyMemory<byte> data)
 			Array.Clear(m_dataOffsetLengths, 0, m_dataOffsetLengths.Length);
 			for (var column = 0; column < m_dataOffsetLengths.Length; column++)
 			{
-				if ((data.Span[(column + 2) / 8 + 1] & (1 << ((column + 2) % 8))) != 0)
+				if ((data.Span[((column + 2) / 8) + 1] & (1 << ((column + 2) % 8))) != 0)
 				{
 					// column is NULL
 					m_dataOffsetLengths[column] = (-1, 0);
@@ -40,7 +41,7 @@ public void SetData(ReadOnlyMemory<byte> data)
 			var reader = new ByteArrayReader(data.Span);
 
 			// skip packet header (1 byte) and NULL bitmap (formula for length at https://dev.mysql.com/doc/internals/en/null-bitmap.html)
-			reader.Offset += 1 + (m_dataOffsetLengths.Length + 7 + 2) / 8;
+			reader.Offset += 1 + ((m_dataOffsetLengths.Length + 7 + 2) / 8);
 			for (var column = 0; column < m_dataOffsetLengths.Length; column++)
 			{
 				if (m_dataOffsetLengths[column].Offset != -1)
@@ -341,7 +342,7 @@ public DateTime GetDateTime(int ordinal)
 		return (DateTime) value;
 	}
 
-	public DateTimeOffset GetDateTimeOffset(int ordinal) => new DateTimeOffset(DateTime.SpecifyKind(GetDateTime(ordinal), DateTimeKind.Utc));
+	public DateTimeOffset GetDateTimeOffset(int ordinal) => new(DateTime.SpecifyKind(GetDateTime(ordinal), DateTimeKind.Utc));
 
 	public Stream GetStream(int ordinal)
 	{
@@ -387,7 +388,7 @@ public float GetFloat(int ordinal)
 		{
 			float floatValue => floatValue,
 			double doubleValue when doubleValue is >= float.MinValue and <= float.MaxValue => (float) doubleValue,
-			double _ => throw new InvalidCastException("The value cannot be safely cast to Single."),
+			double => throw new InvalidCastException("The value cannot be safely cast to Single."),
 			decimal decimalValue => (float) decimalValue,
 			_ => (float) value,
 		};

src/MySqlConnector/Core/SchemaProvider.cs

@@ -1,5 +1,6 @@
+#if NET6_0_OR_GREATER
 using System.Globalization;
-using System.Text;
+#endif
 using MySqlConnector.Protocol.Serialization;
 
 namespace MySqlConnector.Core;
@@ -431,7 +432,7 @@ private async Task FillDataTableAsync(IOBehavior ioBehavior, DataTable dataTable
 			while (await reader.ReadAsync(ioBehavior, cancellationToken).ConfigureAwait(false))
 			{
 				var rowValues = new object[dataTable.Columns.Count];
-				reader.GetValues(rowValues);
+				_ = reader.GetValues(rowValues);
 				dataTable.Rows.Add(rowValues);
 			}
 		}