Code cleanup and formatting for System.Memory files.

src/System.Private.CoreLib/Common/System/SR.cs

@@ -30,7 +30,7 @@ private static bool UsingResourceKeys()
         // Needed for debugger integration
         internal static string GetResourceString(string resourceKey)
         {
-            return GetResourceString(resourceKey, String.Empty);
+            return GetResourceString(resourceKey, string.Empty);
         }
 
         internal static string GetResourceString(string resourceKey, string defaultString)
@@ -155,10 +155,10 @@ internal static string Format(string resourceFormat, params object[] args)
             {
                 if (UsingResourceKeys())
                 {
-                    return resourceFormat + String.Join(", ", args);
+                    return resourceFormat + string.Join(", ", args);
                 }
 
-                return String.Format(resourceFormat, args);
+                return string.Format(resourceFormat, args);
             }
 
             return resourceFormat;
@@ -168,29 +168,29 @@ internal static string Format(string resourceFormat, object p1)
         {
             if (UsingResourceKeys())
             {
-                return String.Join(", ", resourceFormat, p1);
+                return string.Join(", ", resourceFormat, p1);
             }
 
-            return String.Format(resourceFormat, p1);
+            return string.Format(resourceFormat, p1);
         }
 
         internal static string Format(string resourceFormat, object p1, object p2)
         {
             if (UsingResourceKeys())
             {
-                return String.Join(", ", resourceFormat, p1, p2);
+                return string.Join(", ", resourceFormat, p1, p2);
             }
 
-            return String.Format(resourceFormat, p1, p2);
+            return string.Format(resourceFormat, p1, p2);
         }
 
         internal static string Format(string resourceFormat, object p1, object p2, object p3)
         {
             if (UsingResourceKeys())
             {
-                return String.Join(", ", resourceFormat, p1, p2, p3);
+                return string.Join(", ", resourceFormat, p1, p2, p3);
             }
-            return String.Format(resourceFormat, p1, p2, p3);
+            return string.Format(resourceFormat, p1, p2, p3);
         }
     }
 }

src/System.Private.CoreLib/shared/System/ArgumentException.cs

@@ -23,7 +23,7 @@ namespace System
     [System.Runtime.CompilerServices.TypeForwardedFrom("mscorlib, Version=4.0.0.0, Culture=neutral, PublicKeyToken=b77a5c561934e089")]
     public class ArgumentException : SystemException
     {
-        private String _paramName;
+        private string _paramName;
 
         // Creates a new ArgumentException with its message 
         // string set to the empty string. 
@@ -36,26 +36,26 @@ public ArgumentException()
         // Creates a new ArgumentException with its message 
         // string set to message. 
         // 
-        public ArgumentException(String message)
+        public ArgumentException(string message)
             : base(message)
         {
             HResult = HResults.COR_E_ARGUMENT;
         }
 
-        public ArgumentException(String message, Exception innerException)
+        public ArgumentException(string message, Exception innerException)
             : base(message, innerException)
         {
             HResult = HResults.COR_E_ARGUMENT;
         }
 
-        public ArgumentException(String message, String paramName, Exception innerException)
+        public ArgumentException(string message, string paramName, Exception innerException)
             : base(message, innerException)
         {
             _paramName = paramName;
             HResult = HResults.COR_E_ARGUMENT;
         }
 
-        public ArgumentException(String message, String paramName)
+        public ArgumentException(string message, string paramName)
             : base(message)
         {
             _paramName = paramName;
@@ -74,22 +74,22 @@ public override void GetObjectData(SerializationInfo info, StreamingContext cont
             info.AddValue("ParamName", _paramName, typeof(string));
         }
 
-        public override String Message
+        public override string Message
         {
             get
             {
-                String s = base.Message;
-                if (!String.IsNullOrEmpty(_paramName))
+                string s = base.Message;
+                if (!string.IsNullOrEmpty(_paramName))
                 {
-                    String resourceString = SR.Format(SR.Arg_ParamName_Name, _paramName);
+                    string resourceString = SR.Format(SR.Arg_ParamName_Name, _paramName);
                     return s + Environment.NewLine + resourceString;
                 }
                 else
                     return s;
             }
         }
 
-        public virtual String ParamName
+        public virtual string ParamName
         {
             get { return _paramName; }
         }

src/System.Private.CoreLib/shared/System/ArraySegment.cs

@@ -289,7 +289,7 @@ bool ICollection<T>.Contains(T item)
         bool ICollection<T>.Remove(T item)
         {
             ThrowHelper.ThrowNotSupportedException();
-            return default(bool);
+            return default;
         }
         #endregion
 

src/System.Private.CoreLib/shared/System/Buffers/MemoryHandle.cs

@@ -2,7 +2,6 @@
 // The .NET Foundation licenses this file to you under the MIT license.
 // See the LICENSE file in the project root for more information.
 
-using System.Runtime;
 using System.Runtime.InteropServices;
 
 namespace System.Buffers

src/System.Private.CoreLib/shared/System/Buffers/MemoryManager.cs

@@ -2,7 +2,6 @@
 // The .NET Foundation licenses this file to you under the MIT license.
 // See the LICENSE file in the project root for more information.
 
-using System.Runtime;
 using System.Runtime.CompilerServices;
 
 namespace System.Buffers

src/System.Private.CoreLib/shared/System/Collections/Concurrent/ConcurrentQueue.cs

@@ -175,7 +175,7 @@ void ICollection.CopyTo(Array array, int index)
         /// cref="ICollection"/>. This property is not supported.
         /// </summary>
         /// <exception cref="NotSupportedException">The SyncRoot property is not supported.</exception>
-        object ICollection.SyncRoot { get { ThrowHelper.ThrowNotSupportedException(ExceptionResource.ConcurrentCollection_SyncRoot_NotSupported); return default(object); } }
+        object ICollection.SyncRoot { get { ThrowHelper.ThrowNotSupportedException(ExceptionResource.ConcurrentCollection_SyncRoot_NotSupported); return default; } }
 
         /// <summary>Returns an enumerator that iterates through a collection.</summary>
         /// <returns>An <see cref="IEnumerator"/> that can be used to iterate through the collection.</returns>
@@ -713,7 +713,7 @@ private bool TryDequeueSlow(out T item)
                 // check and this check, another item could have arrived).
                 if (head._nextSegment == null)
                 {
-                    item = default(T);
+                    item = default;
                     return false;
                 }
 
@@ -807,7 +807,7 @@ private bool TryPeek(out T result, bool resultUsed)
                 // and we'll traverse to that segment.
             }
 
-            result = default(T);
+            result = default;
             return false;
         }
 

src/System.Private.CoreLib/shared/System/Convert.cs

@@ -316,7 +316,7 @@ public static Object ChangeType(Object value, Type conversionType)
 
         public static Object ChangeType(Object value, Type conversionType, IFormatProvider provider)
         {
-            if (ReferenceEquals(conversionType, null))
+            if (conversionType is null)
             {
                 throw new ArgumentNullException(nameof(conversionType));
             }
@@ -2008,7 +2008,7 @@ public static string ToString(Object value, IFormatProvider provider)
             IFormattable formattable = value as IFormattable;
             if (formattable != null)
                 return formattable.ToString(null, provider);
-            return value == null ? String.Empty : value.ToString();
+            return value == null ? string.Empty : value.ToString();
         }
 
         public static string ToString(bool value)

src/System.Private.CoreLib/shared/System/DateTimeOffset.cs

@@ -806,7 +806,7 @@ public static Boolean TryParse(String input, IFormatProvider formatProvider, Dat
             styles = ValidateStyles(styles, nameof(styles));
             if (input == null)
             {
-                result = default(DateTimeOffset);
+                result = default;
                 return false;
             }
 
@@ -835,7 +835,7 @@ public static Boolean TryParseExact(String input, String format, IFormatProvider
             styles = ValidateStyles(styles, nameof(styles));
             if (input == null || format == null)
             {
-                result = default(DateTimeOffset);
+                result = default;
                 return false;
             }
 
@@ -866,7 +866,7 @@ public static Boolean TryParseExact(String input, String[] formats, IFormatProvi
             styles = ValidateStyles(styles, nameof(styles));
             if (input == null)
             {
-                result = default(DateTimeOffset);
+                result = default;
                 return false;
             }
 

src/System.Private.CoreLib/shared/System/Diagnostics/Tracing/EventProvider.cs

@@ -959,7 +959,7 @@ internal unsafe bool WriteEvent(ref EventDescriptor eventDescriptor, IntPtr even
                     List<object> dataRefObj = new List<object>(s_etwAPIMaxRefObjCount);
                     EventData* userData = stackalloc EventData[2 * argCount];
                     for (int i = 0; i < 2 * argCount; i++)
-                        userData[i] = default(EventData);
+                        userData[i] = default;
                     EventData* userDataPtr = (EventData*)userData;
                     byte* dataBuffer = stackalloc byte[s_basicTypeAllocationBufferSize * 2 * argCount]; // Assume 16 chars for non-string argument
                     byte* currentBuffer = dataBuffer;

src/System.Private.CoreLib/shared/System/Diagnostics/Tracing/EventSource.cs

@@ -3168,7 +3168,7 @@ private static byte[] CreateManifestAndDescriptors(Type eventSourceType, string
 
             if ((flags & EventManifestOptions.Strict) != 0 && (manifest.Errors.Count > 0 || exception != null))
             {
-                string msg = String.Empty;
+                string msg = string.Empty;
                 if (manifest.Errors.Count > 0)
                 {
                     bool firstError = true;
@@ -3550,7 +3550,7 @@ internal void ReportOutOfBandMessage(string msg, bool flush)
             {
 #if (!ES_BUILD_PCL && !ES_BUILD_PN)
                 // send message to debugger without delay
-                System.Diagnostics.Debugger.Log(0, null, String.Format("EventSource Error: {0}{1}", msg, Environment.NewLine));
+                System.Diagnostics.Debugger.Log(0, null, string.Format("EventSource Error: {0}{1}", msg, Environment.NewLine));
 #endif
 
                 // Send it to all listeners.
@@ -4231,7 +4231,7 @@ public class EventCommandEventArgs : EventArgs
         /// <summary>
         /// Gets the arguments for the callback.
         /// </summary>
-        public IDictionary<String, String> Arguments { get; internal set; }
+        public IDictionary<string, string> Arguments { get; internal set; }
 
         /// <summary>
         /// Enables the event that has the specified identifier.

src/System.Private.CoreLib/shared/System/Diagnostics/Tracing/StubEnvironment.cs

@@ -30,10 +30,10 @@ public static string GetResourceString(string key, params object[] args)
             if (fmt != null)
                 return string.Format(fmt, args);
 
-            string sargs = String.Empty;
+            string sargs = string.Empty;
             foreach(var arg in args)
             {
-                if (sargs != String.Empty)
+                if (sargs != string.Empty)
                     sargs += ", ";
                 sargs += arg.ToString();
             }

src/System.Private.CoreLib/shared/System/Diagnostics/Tracing/TraceLogging/EventPayload.cs

@@ -144,7 +144,7 @@ public bool TryGetValue(string key, out object value)
                 position++;
             }
 
-            value = default(object);
+            value = default;
             return false;
         }
 

src/System.Private.CoreLib/shared/System/Diagnostics/Tracing/TraceLogging/PropertyValue.cs

@@ -87,7 +87,7 @@ public struct Scalar
         private PropertyValue(object value)
         {
             _reference = value;
-            _scalar = default(Scalar);
+            _scalar = default;
             _scalarLength = 0;
         }
 

src/System.Private.CoreLib/shared/System/Diagnostics/Tracing/TraceLogging/TraceLoggingEventSource.cs

@@ -447,11 +447,11 @@ private unsafe void WriteMultiMergeInner(
             var scratch = stackalloc byte[eventTypes.scratchSize];
             var descriptors = stackalloc EventData[eventTypes.dataCount + 3];
             for(int i = 0; i < eventTypes.dataCount + 3; i++)
-                descriptors[i] = default(EventData);
+                descriptors[i] = default;
 
             var pins = stackalloc GCHandle[pinCount];
             for (int i = 0; i < pinCount; i++)
-                pins[i] = default(GCHandle);
+                pins[i] = default;
 
             fixed (byte*
                 pMetadata0 = this.providerMetadata,
@@ -563,7 +563,7 @@ internal unsafe void WriteMultiMerge(
                 var descriptorsLength = eventTypes.dataCount + eventTypes.typeInfos.Length * 2 + 3;
                 var descriptors = stackalloc EventData[descriptorsLength];
                 for(int i = 0; i < descriptorsLength; i++)
-                    descriptors[i] = default(EventData);
+                    descriptors[i] = default;
 
                 fixed (byte*
                     pMetadata0 = this.providerMetadata,
@@ -632,11 +632,11 @@ private unsafe void WriteImpl(
                     var scratch = stackalloc byte[eventTypes.scratchSize];
                     var descriptors = stackalloc EventData[eventTypes.dataCount + 3];
                     for(int i=0; i<eventTypes.dataCount + 3; i++)
-                        descriptors[i] = default(EventData);
+                        descriptors[i] = default;
 
                     var pins = stackalloc GCHandle[pinCount];
                     for (int i = 0; i < pinCount; i++)
-                        pins[i] = default(GCHandle);
+                        pins[i] = default;
 
                     fixed (byte*
                         pMetadata0 = this.providerMetadata,

src/System.Private.CoreLib/shared/System/Globalization/Calendar.cs

@@ -206,7 +206,7 @@ internal static void CheckAddResult(long ticks, DateTime minValue, DateTime maxV
             if (ticks < minValue.Ticks || ticks > maxValue.Ticks)
             {
                 throw new ArgumentException(
-                    String.Format(CultureInfo.InvariantCulture, SR.Format(SR.Argument_ResultCalendarRange,
+                    string.Format(CultureInfo.InvariantCulture, SR.Format(SR.Argument_ResultCalendarRange,
                         minValue, maxValue)));
             }
         }
@@ -818,7 +818,7 @@ internal static long TimeToTicks(int hour, int minute, int second, int milliseco
                 {
                     throw new ArgumentOutOfRangeException(
                                 nameof(millisecond),
-                                String.Format(
+                                string.Format(
                                     CultureInfo.InvariantCulture,
                                     SR.Format(SR.ArgumentOutOfRange_Range, 0, MillisPerSecond - 1)));
                 }