Replace a few stackallocs with collection expressions (#105143)

* Replace a few stackallocs with collection expressions

* Update src/libraries/System.Text.Encodings.Web/src/System/Text/Encodings/Web/OptimizedInboxTextEncoder.Ascii.cs

src/libraries/Common/src/Extensions/Logging/DebuggerDisplayFormatting.cs

@@ -31,15 +31,15 @@ internal static string DebuggerToString(string name, ILogger logger)
 
  internal static LogLevel? CalculateEnabledLogLevel(ILogger logger)
  {
- ReadOnlySpan<LogLevel> logLevels = stackalloc LogLevel[]
- {
+ ReadOnlySpan<LogLevel> logLevels =
+ [
  LogLevel.Critical,
  LogLevel.Error,
  LogLevel.Warning,
  LogLevel.Information,
  LogLevel.Debug,
  LogLevel.Trace,
- };
+ ];
 
  LogLevel? minimumLevel = null;
 

src/libraries/Common/src/System/Net/Security/MD4.cs

@@ -66,9 +66,10 @@ internal static void HashData(ReadOnlySpan<byte> source, Span<byte> destination)
 
  Span<byte> buffer = stackalloc byte[64];
  buffer.Clear();
+
  // Initialize the context
- Span<uint> state = stackalloc uint[4] { 0x67452301, 0xefcdab89, 0x98badcfe, 0x10325476 };
- Span<uint> count = stackalloc uint[2] { 0, 0 };
+ Span<uint> state = [0x67452301, 0xefcdab89, 0x98badcfe, 0x10325476];
+ Span<uint> count = [0, 0];
 
  HashCore(source, state, count, buffer);
 

src/libraries/Microsoft.Bcl.Cryptography/src/System/Security/Cryptography/SP800108HmacCounterKdfImplementationCng.cs

@@ -38,7 +38,7 @@ internal unsafe SP800108HmacCounterKdfImplementationCng(ReadOnlySpan<byte> key,
  else
  {
  // CNG requires a non-null pointer even when the length is zero.
- symmetricKeyMaterial = stackalloc byte[] { 0 };
+ symmetricKeyMaterial = [0];
  symmetricKeyMaterialLength = 0;
  }
 
@@ -82,7 +82,7 @@ internal unsafe SP800108HmacCounterKdfImplementationCng(byte[] key, HashAlgorith
  else
  {
  // CNG requires a non-null pointer even when the length is zero.
- symmetricKeyMaterial = stackalloc byte[] { 0 };
+ symmetricKeyMaterial = [0];
  symmetricKeyMaterialLength = 0;
  }
 

src/libraries/Microsoft.Extensions.Logging/src/Logger.cs

@@ -238,15 +238,15 @@ private sealed class LoggerProviderDebugView(string providerName, MessageLogger?
  return null;
  }
 
- ReadOnlySpan<LogLevel> logLevels = stackalloc LogLevel[]
- {
+ ReadOnlySpan<LogLevel> logLevels =
+ [
  LogLevel.Critical,
  LogLevel.Error,
  LogLevel.Warning,
  LogLevel.Information,
  LogLevel.Debug,
  LogLevel.Trace,
- };
+ ];
 
  LogLevel? minimumLevel = null;
 

src/libraries/System.Private.CoreLib/src/System/StartupHookProvider.cs

@@ -85,13 +85,13 @@ private static unsafe void CallStartupHook(char* pStartupHookPart)
 
  private static void ParseStartupHook(ref StartupHookNameOrPath startupHook, string startupHookPart)
  {
- ReadOnlySpan<char> disallowedSimpleAssemblyNameChars = stackalloc char[4]
- {
+ ReadOnlySpan<char> disallowedSimpleAssemblyNameChars =
+ [
  Path.DirectorySeparatorChar,
  Path.AltDirectorySeparatorChar,
  ' ',
  ','
- };
+ ];
 
  if (string.IsNullOrEmpty(startupHookPart))
  {

src/libraries/System.Private.DataContractSerialization/src/System/Xml/XmlBufferReader.cs

@@ -396,13 +396,13 @@ public decimal ReadDecimal()
  {
  byte[] buffer = GetBuffer(ValueHandleLength.Decimal, out int offset);
  ReadOnlySpan<byte> bytes = buffer.AsSpan(offset, sizeof(decimal));
- ReadOnlySpan<int> span = stackalloc int[4]
- {
+ ReadOnlySpan<int> span =
+ [
  BinaryPrimitives.ReadInt32LittleEndian(bytes.Slice(8, 4)),
  BinaryPrimitives.ReadInt32LittleEndian(bytes.Slice(12, 4)),
  BinaryPrimitives.ReadInt32LittleEndian(bytes.Slice(4, 4)),
  BinaryPrimitives.ReadInt32LittleEndian(bytes.Slice(0, 4))
- };
+ ];
 
  Advance(ValueHandleLength.Decimal);
  return new decimal(span);
@@ -975,13 +975,13 @@ public decimal GetDecimal(int offset)
  else
  {
  ReadOnlySpan<byte> bytes = _buffer.AsSpan(offset, sizeof(decimal));
- ReadOnlySpan<int> span = stackalloc int[4]
- {
+ ReadOnlySpan<int> span =
+ [
  BinaryPrimitives.ReadInt32LittleEndian(bytes.Slice(8, 4)),
  BinaryPrimitives.ReadInt32LittleEndian(bytes.Slice(12, 4)),
  BinaryPrimitives.ReadInt32LittleEndian(bytes.Slice(4, 4)),
  BinaryPrimitives.ReadInt32LittleEndian(bytes.Slice(0, 4))
- };
+ ];
 
  return new decimal(span);
  }

src/libraries/System.Security.Cryptography.Cose/src/System/Security/Cryptography/Cose/CoseHelpers.cs

@@ -47,12 +47,12 @@ internal static void WriteByteStringLength(IncrementalHash hasher, ulong value)
  if (value < (byte)CborAdditionalInfo.Additional8BitData)
  {
  initialByte = new CborInitialByte(MajorType, (CborAdditionalInfo)value);
- hasher.AppendData(stackalloc byte[] { initialByte.InitialByte });
+ hasher.AppendData([initialByte.InitialByte]);
  }
  else if (value <= byte.MaxValue)
  {
  initialByte = new CborInitialByte(MajorType, CborAdditionalInfo.Additional8BitData);
- hasher.AppendData(stackalloc byte[] { initialByte.InitialByte, (byte)value });
+ hasher.AppendData([initialByte.InitialByte, (byte)value]);
  }
  else if (value <= ushort.MaxValue)
  {

src/libraries/System.Security.Cryptography.Pkcs/src/System/Security/Cryptography/Pkcs/CmsSignature.RSA.cs

@@ -186,9 +186,7 @@ protected override RSASignaturePadding GetSignaturePadding(
  return RSASignaturePadding.Pkcs1;
  }
 
- Span<byte> expectedParameters = stackalloc byte[2];
- expectedParameters[0] = 0x05;
- expectedParameters[1] = 0x00;
+ ReadOnlySpan<byte> expectedParameters = [0x05, 0x00];
 
  if (expectedParameters.SequenceEqual(signatureParameters.Value.Span))
  {

src/libraries/System.Security.Cryptography/src/System/Security/Cryptography/Pbkdf2Implementation.Windows.cs

@@ -60,7 +60,7 @@ private static unsafe void FillKeyDerivation(
  if (password.IsEmpty)
  {
  // CNG won't accept a null pointer for the password.
- symmetricKeyMaterial = stackalloc byte[1];
+ symmetricKeyMaterial = [0];
  symmetricKeyMaterialLength = 0;
  clearSpan = default;
  }

src/libraries/System.Text.Encodings.Web/src/System/Text/Encodings/Web/DefaultJavaScriptEncoder.cs

@@ -31,9 +31,9 @@ private DefaultJavaScriptEncoder(TextEncoderSettings settings, bool allowMinimal
 
  _innerEncoder = allowMinimalJsonEscaping
  ? new OptimizedInboxTextEncoder(EscaperImplementation.SingletonMinimallyEscaped, settings.GetAllowedCodePointsBitmap(), forbidHtmlSensitiveCharacters: false,
- extraCharactersToEscape: stackalloc char[] { '\"', '\\' })
+ extraCharactersToEscape: ['\"', '\\'])
  : new OptimizedInboxTextEncoder(EscaperImplementation.Singleton, settings.GetAllowedCodePointsBitmap(), forbidHtmlSensitiveCharacters: true,
- extraCharactersToEscape: stackalloc char[] { '\\', '`' });
+ extraCharactersToEscape: ['\\', '`']);
  }
 
  public override int MaxOutputCharactersPerInputCharacter => 6; // "\uXXXX" for a single char ("\uXXXX\uYYYY" [12 chars] for supplementary scalar value)

src/libraries/System.Text.Encodings.Web/src/System/Text/Encodings/Web/DefaultUrlEncoder.cs

@@ -64,7 +64,7 @@ internal DefaultUrlEncoder(TextEncoderSettings settings)
  // Basic Latin set is:
  // ALPHA / DIGIT / "-" / "." / "_" / "~" / "!" / "$" / "(" / ")" / "*" / "," / ";" / "@"
 
- _innerEncoder = new OptimizedInboxTextEncoder(EscaperImplementation.Singleton, settings.GetAllowedCodePointsBitmap(), extraCharactersToEscape: stackalloc char[] {
+ _innerEncoder = new OptimizedInboxTextEncoder(EscaperImplementation.Singleton, settings.GetAllowedCodePointsBitmap(), extraCharactersToEscape: [
  ' ', // chars from Basic Latin which aren't already disallowed by the base encoder
  '#',
  '%',
@@ -96,7 +96,7 @@ internal DefaultUrlEncoder(TextEncoderSettings settings)
  '\uFFFD',
  '\uFFFE',
  '\uFFFF',
- });
+ ]);
  }
 
  public override int MaxOutputCharactersPerInputCharacter => 9; // "%XX%YY%ZZ" for a single char ("%XX%YY%ZZ%WW" [12 chars] for supplementary scalar value)

src/libraries/System.Text.RegularExpressions/src/System/Text/RegularExpressions/RegexCharClass.cs

@@ -1541,7 +1541,7 @@ private static RegexCharClass ParseRecursive(string charClass, int start)
  /// <param name="c">The character for which to create the set.</param>
  /// <returns>The create set string.</returns>
  public static string OneToStringClass(char c)
- => CharsToStringClass(stackalloc char[1] { c });
+ => CharsToStringClass([c]);
 
  internal static unsafe string CharsToStringClass(ReadOnlySpan<char> chars)
  {