Nullable: All remaining exceptions

src/System.Private.CoreLib/shared/Internal/Resources/PRIExceptionInfo.cs

@@ -2,13 +2,12 @@
 // 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;
-
+#nullable enable
 namespace Internal.Resources
 {
     public class PRIExceptionInfo
     {
-        public string PackageSimpleName;
-        public string ResWFile;
+        public string? PackageSimpleName;
+        public string? ResWFile;
     }
 }

src/System.Private.CoreLib/shared/System/Collections/Generic/KeyNotFoundException.cs

@@ -2,7 +2,7 @@
 // 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;
+#nullable enable
 using System.Runtime.Serialization;
 
 namespace System.Collections.Generic
@@ -17,13 +17,13 @@ public KeyNotFoundException()
             HResult = HResults.COR_E_KEYNOTFOUND;
         }
 
-        public KeyNotFoundException(string message)
+        public KeyNotFoundException(string? message)
             : base(message)
         {
             HResult = HResults.COR_E_KEYNOTFOUND;
         }
 
-        public KeyNotFoundException(string message, Exception innerException)
+        public KeyNotFoundException(string? message, Exception? innerException)
             : base(message, innerException)
         {
             HResult = HResults.COR_E_KEYNOTFOUND;

src/System.Private.CoreLib/shared/System/Diagnostics/Contracts/ContractException.cs

@@ -2,11 +2,7 @@
 // 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;
-using System.Collections.Generic;
-using System.Diagnostics;
-using System.Diagnostics.CodeAnalysis;
-using System.Reflection;
+#nullable enable
 using System.Runtime.Serialization;
 
 namespace System.Diagnostics.Contracts
@@ -17,21 +13,21 @@ namespace System.Diagnostics.Contracts
     public sealed class ContractException : Exception
     {
         private readonly ContractFailureKind _kind;
-        private readonly string _userMessage;
-        private readonly string _condition;
+        private readonly string? _userMessage;
+        private readonly string? _condition;
 
-        public ContractFailureKind Kind { get { return _kind; } }
-        public string Failure { get { return this.Message; } }
-        public string UserMessage { get { return _userMessage; } }
-        public string Condition { get { return _condition; } }
+        public ContractFailureKind Kind => _kind;
+        public string Failure => this.Message;
+        public string? UserMessage => _userMessage;
+        public string? Condition => _condition;
 
         // Called by COM Interop, if we see COR_E_CODECONTRACTFAILED as an HRESULT.
         private ContractException()
         {
             HResult = HResults.COR_E_CODECONTRACTFAILED;
         }
 
-        public ContractException(ContractFailureKind kind, string failure, string userMessage, string condition, Exception innerException)
+        public ContractException(ContractFailureKind kind, string? failure, string? userMessage, string? condition, Exception? innerException)
             : base(failure, innerException)
         {
             HResult = HResults.COR_E_CODECONTRACTFAILED;

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

@@ -2,8 +2,7 @@
 // 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;
-using System.Resources;
+#nullable enable
 using System.Runtime.Serialization;
 
 #if ES_BUILD_STANDALONE
@@ -33,13 +32,13 @@ public EventSourceException() :
         /// <summary>
         /// Initializes a new instance of the EventSourceException class with a specified error message.
         /// </summary>
-        public EventSourceException(string message) : base(message) { }
+        public EventSourceException(string? message) : base(message) { }
 
         /// <summary>
         /// Initializes a new instance of the EventSourceException class with a specified error message 
         /// and a reference to the inner exception that is the cause of this exception.
         /// </summary>
-        public EventSourceException(string message, Exception innerException) : base(message, innerException) { }
+        public EventSourceException(string? message, Exception? innerException) : base(message, innerException) { }
 
 #if !ES_BUILD_PCL
         /// <summary>
@@ -48,7 +47,7 @@ public EventSourceException(string message, Exception innerException) : base(mes
         protected EventSourceException(SerializationInfo info, StreamingContext context) : base(info, context) { }
 #endif
 
-        internal EventSourceException(Exception innerException) :
+        internal EventSourceException(Exception? innerException) :
             base(SR.EventSource_ListenerWriteFailure, innerException) { }
     }
 }

src/System.Private.CoreLib/shared/System/IO/DirectoryNotFoundException.cs

@@ -2,6 +2,7 @@
 // The .NET Foundation licenses this file to you under the MIT license.
 // See the LICENSE file in the project root for more information.
 
+#nullable enable
 using System.Runtime.Serialization;
 
 namespace System.IO
@@ -22,13 +23,13 @@ public DirectoryNotFoundException()
             HResult = HResults.COR_E_DIRECTORYNOTFOUND;
         }
 
-        public DirectoryNotFoundException(string message)
+        public DirectoryNotFoundException(string? message)
             : base(message)
         {
             HResult = HResults.COR_E_DIRECTORYNOTFOUND;
         }
 
-        public DirectoryNotFoundException(string message, Exception innerException)
+        public DirectoryNotFoundException(string? message, Exception? innerException)
             : base(message, innerException)
         {
             HResult = HResults.COR_E_DIRECTORYNOTFOUND;

src/System.Private.CoreLib/shared/System/IO/EndOfStreamException.cs

@@ -2,6 +2,7 @@
 // The .NET Foundation licenses this file to you under the MIT license.
 // See the LICENSE file in the project root for more information.
 
+#nullable enable
 using System.Runtime.Serialization;
 
 namespace System.IO
@@ -16,13 +17,13 @@ public EndOfStreamException()
             HResult = HResults.COR_E_ENDOFSTREAM;
         }
 
-        public EndOfStreamException(string message)
+        public EndOfStreamException(string? message)
             : base(message)
         {
             HResult = HResults.COR_E_ENDOFSTREAM;
         }
 
-        public EndOfStreamException(string message, Exception innerException)
+        public EndOfStreamException(string? message, Exception? innerException)
             : base(message, innerException)
         {
             HResult = HResults.COR_E_ENDOFSTREAM;

src/System.Private.CoreLib/shared/System/IO/FileLoadException.cs

@@ -2,6 +2,7 @@
 // The .NET Foundation licenses this file to you under the MIT license.
 // See the LICENSE file in the project root for more information.
 
+#nullable enable
 using System.Runtime.Serialization;
 
 namespace System.IO
@@ -16,25 +17,25 @@ public FileLoadException()
             HResult = HResults.COR_E_FILELOAD;
         }
 
-        public FileLoadException(string message)
+        public FileLoadException(string? message)
             : base(message)
         {
             HResult = HResults.COR_E_FILELOAD;
         }
 
-        public FileLoadException(string message, Exception inner)
+        public FileLoadException(string? message, Exception? inner)
             : base(message, inner)
         {
             HResult = HResults.COR_E_FILELOAD;
         }
 
-        public FileLoadException(string message, string fileName) : base(message)
+        public FileLoadException(string? message, string? fileName) : base(message)
         {
             HResult = HResults.COR_E_FILELOAD;
             FileName = fileName;
         }
 
-        public FileLoadException(string message, string fileName, Exception inner)
+        public FileLoadException(string? message, string? fileName, Exception? inner)
             : base(message, inner)
         {
             HResult = HResults.COR_E_FILELOAD;
@@ -53,8 +54,8 @@ public override string Message
             }
         }
 
-        public string FileName { get; }
-        public string FusionLog { get; }
+        public string? FileName { get; }
+        public string? FusionLog { get; }
 
         public override string ToString()
         {

src/System.Private.CoreLib/shared/System/IO/FileNotFoundException.cs

@@ -2,6 +2,8 @@
 // The .NET Foundation licenses this file to you under the MIT license.
 // See the LICENSE file in the project root for more information.
 
+#nullable enable
+using System.Diagnostics;
 using System.Runtime.Serialization;
 
 namespace System.IO
@@ -17,26 +19,26 @@ public FileNotFoundException()
             HResult = HResults.COR_E_FILENOTFOUND;
         }
 
-        public FileNotFoundException(string message)
+        public FileNotFoundException(string? message)
             : base(message)
         {
             HResult = HResults.COR_E_FILENOTFOUND;
         }
 
-        public FileNotFoundException(string message, Exception innerException)
+        public FileNotFoundException(string? message, Exception? innerException)
             : base(message, innerException)
         {
             HResult = HResults.COR_E_FILENOTFOUND;
         }
 
-        public FileNotFoundException(string message, string fileName) 
+        public FileNotFoundException(string? message, string? fileName) 
             : base(message)
         {
             HResult = HResults.COR_E_FILENOTFOUND;
             FileName = fileName;
         }
 
-        public FileNotFoundException(string message, string fileName, Exception innerException)
+        public FileNotFoundException(string? message, string? fileName, Exception? innerException)
             : base(message, innerException)
         {
             HResult = HResults.COR_E_FILENOTFOUND;
@@ -48,6 +50,7 @@ public override string Message
             get
             {
                 SetMessageField();
+                Debug.Assert(_message != null, "_message was null after calling SetMessageField");
                 return _message;
             }
         }
@@ -65,8 +68,8 @@ private void SetMessageField()
             }
         }
 
-        public string FileName { get; }
-        public string FusionLog { get; }
+        public string? FileName { get; }
+        public string? FusionLog { get; }
 
         public override string ToString()
         {

src/System.Private.CoreLib/shared/System/IO/IOException.cs

@@ -2,7 +2,7 @@
 // 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;
+#nullable enable
 using System.Runtime.Serialization;
 
 namespace System.IO
@@ -17,19 +17,19 @@ public IOException()
             HResult = HResults.COR_E_IO;
         }
 
-        public IOException(string message)
+        public IOException(string? message)
             : base(message)
         {
             HResult = HResults.COR_E_IO;
         }
 
-        public IOException(string message, int hresult)
+        public IOException(string? message, int hresult)
             : base(message)
         {
             HResult = hresult;
         }
 
-        public IOException(string message, Exception innerException)
+        public IOException(string? message, Exception? innerException)
             : base(message, innerException)
         {
             HResult = HResults.COR_E_IO;

src/System.Private.CoreLib/shared/System/IO/PathTooLongException.cs

@@ -2,8 +2,7 @@
 // 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;
+#nullable enable
 using System.Runtime.Serialization;
 
 namespace System.IO
@@ -18,13 +17,13 @@ public PathTooLongException()
             HResult = HResults.COR_E_PATHTOOLONG;
         }
 
-        public PathTooLongException(string message)
+        public PathTooLongException(string? message)
             : base(message)
         {
             HResult = HResults.COR_E_PATHTOOLONG;
         }
 
-        public PathTooLongException(string message, Exception innerException)
+        public PathTooLongException(string? message, Exception? innerException)
             : base(message, innerException)
         {
             HResult = HResults.COR_E_PATHTOOLONG;

src/System.Private.CoreLib/shared/System/Reflection/AmbiguousMatchException.cs

@@ -2,6 +2,7 @@
 // The .NET Foundation licenses this file to you under the MIT license.
 // See the LICENSE file in the project root for more information.
 
+#nullable enable
 using System.Runtime.Serialization;
 
 namespace System.Reflection
@@ -16,13 +17,13 @@ public AmbiguousMatchException()
             HResult = HResults.COR_E_AMBIGUOUSMATCH;
         }
 
-        public AmbiguousMatchException(string message)
+        public AmbiguousMatchException(string? message)
             : base(message)
         {
             HResult = HResults.COR_E_AMBIGUOUSMATCH;
         }
 
-        public AmbiguousMatchException(string message, Exception inner)
+        public AmbiguousMatchException(string? message, Exception? inner)
             : base(message, inner)
         {
             HResult = HResults.COR_E_AMBIGUOUSMATCH;

src/System.Private.CoreLib/shared/System/Reflection/CustomAttributeFormatException.cs

@@ -2,6 +2,7 @@
 // The .NET Foundation licenses this file to you under the MIT license.
 // See the LICENSE file in the project root for more information.
 
+#nullable enable
 using System.Runtime.Serialization;
 
 namespace System.Reflection
@@ -15,12 +16,12 @@ public CustomAttributeFormatException()
         {
         }
 
-        public CustomAttributeFormatException(string message)
+        public CustomAttributeFormatException(string? message)
             : this(message, null)
         {
         }
 
-        public CustomAttributeFormatException(string message, Exception inner)
+        public CustomAttributeFormatException(string? message, Exception? inner)
             : base(message, inner)
         {
             HResult = HResults.COR_E_CUSTOMATTRIBUTEFORMAT;