Merge master to features/local-function-attributes

src/CodeStyle/Core/Analyzers/Microsoft.CodeAnalysis.CodeStyle.csproj

@@ -27,12 +27,14 @@
     <InternalsVisibleTo Include="Microsoft.CodeAnalysis.VisualBasic.CodeStyle.UnitTests" />
   </ItemGroup>
   <ItemGroup>
+    <Compile Include="..\..\..\Compilers\Core\Portable\InternalUtilities\Debug.cs" Link="Formatting\Debug.cs" />
     <Compile Include="..\..\..\Compilers\Core\Portable\InternalUtilities\EnumerableExtensions.cs" Link="Formatting\EnumerableExtensions.cs" />
     <Compile Include="..\..\..\Compilers\Core\Portable\InternalUtilities\ExceptionUtilities.cs" Link="InternalUtilities\ExceptionUtilities.cs" />
     <Compile Include="..\..\..\Compilers\Core\Portable\InternalUtilities\IReadOnlySet.cs" Link="InternalUtilities\IReadOnlySet.cs" />
     <Compile Include="..\..\..\Compilers\Core\Portable\InternalUtilities\KeyValuePairUtil.cs" Link="InternalUtilities\KeyValuePairUtil.cs" />
     <Compile Include="..\..\..\Compilers\Core\Portable\InternalUtilities\NullableAttributes.cs" Link="Formatting\NullableAttributes.cs" />
     <Compile Include="..\..\..\Compilers\Core\Portable\InternalUtilities\PerformanceSensitiveAttribute.cs" Link="PerformanceSensitiveAttribute.cs" />
+    <Compile Include="..\..\..\Compilers\Core\Portable\InternalUtilities\RoslynString.cs" Link="RoslynString.cs" />
     <Compile Include="..\..\..\Compilers\Core\Portable\InternalUtilities\SpecializedCollections.cs" Link="InternalUtilities\SpecializedCollections.cs" />
     <Compile Include="..\..\..\Compilers\Core\Portable\InternalUtilities\SpecializedCollections.Empty.Collection.cs" Link="InternalUtilities\SpecializedCollections.Empty.Collection.cs" />
     <Compile Include="..\..\..\Compilers\Core\Portable\InternalUtilities\SpecializedCollections.Empty.cs" Link="InternalUtilities\SpecializedCollections.Empty.cs" />

src/Compilers/Core/MSBuildTask/Microsoft.Build.Tasks.CodeAnalysis.csproj

@@ -39,8 +39,10 @@
     <Compile Include="..\Portable\InternalUtilities\CommandLineUtilities.cs" />
     <Compile Include="..\Portable\InternalUtilities\CompilerOptionParseUtilities.cs" />
     <Compile Include="..\Portable\InternalUtilities\IReadOnlySet.cs" />
+    <Compile Include="..\Portable\InternalUtilities\NullableAttributes.cs" />
     <Compile Include="..\Portable\InternalUtilities\PlatformInformation.cs" />
     <Compile Include="..\Portable\InternalUtilities\ReflectionUtilities.cs" />
+    <Compile Include="..\Portable\InternalUtilities\RoslynString.cs" />
     <Compile Include="..\Portable\InternalUtilities\UnicodeCharacterUtilities.cs" />
     <Compile Update="ErrorString.Designer.cs">
       <AutoGen>True</AutoGen>

src/Compilers/Core/Portable/Collections/ArrayBuilderExtensions.cs

@@ -1,5 +1,7 @@
 // Copyright (c) Microsoft.  All Rights Reserved.  Licensed under the Apache License, Version 2.0.  See License.txt in the project root for license information.
 
+#nullable enable
+
 using System;
 using System.Collections.Immutable;
 using Microsoft.CodeAnalysis.PooledObjects;
@@ -134,7 +136,7 @@ public static ImmutableArray<TResult> SelectAsArray<TItem, TArg, TResult>(this A
             }
         }
 
-        public static void AddOptional<T>(this ArrayBuilder<T> builder, T item)
+        public static void AddOptional<T>(this ArrayBuilder<T> builder, T? item)
             where T : class
         {
             if (item != null)
@@ -163,9 +165,9 @@ public static T Peek<T>(this ArrayBuilder<T> builder)
             return builder[builder.Count - 1];
         }
 
-        public static ImmutableArray<T> ToImmutableOrEmptyAndFree<T>(this ArrayBuilder<T> builderOpt)
+        public static ImmutableArray<T> ToImmutableOrEmptyAndFree<T>(this ArrayBuilder<T>? builder)
         {
-            return builderOpt?.ToImmutableAndFree() ?? ImmutableArray<T>.Empty;
+            return builder?.ToImmutableAndFree() ?? ImmutableArray<T>.Empty;
         }
 
         public static void AddIfNotNull<T>(this ArrayBuilder<T> builder, T? value)
@@ -177,7 +179,7 @@ public static void AddIfNotNull<T>(this ArrayBuilder<T> builder, T? value)
             }
         }
 
-        public static void AddIfNotNull<T>(this ArrayBuilder<T> builder, T value)
+        public static void AddIfNotNull<T>(this ArrayBuilder<T> builder, T? value)
             where T : class
         {
             if (value != null)
@@ -186,6 +188,7 @@ public static void AddIfNotNull<T>(this ArrayBuilder<T> builder, T value)
             }
         }
 
+#nullable disable
         public static void FreeAll<T>(this ArrayBuilder<T> builder, Func<T, ArrayBuilder<T>> getNested)
         {
             foreach (var item in builder)
@@ -194,5 +197,6 @@ public static void FreeAll<T>(this ArrayBuilder<T> builder, Func<T, ArrayBuilder
             }
             builder.Free();
         }
+#nullable enable
     }
 }

src/Compilers/Core/Portable/Collections/ArrayElement.cs

@@ -1,6 +1,9 @@
 // Copyright (c) Microsoft.  All Rights Reserved.  Licensed under the Apache License, Version 2.0.  See License.txt in the project root for license information.
 
+#nullable enable
+
 using System.Diagnostics;
+using System.Diagnostics.CodeAnalysis;
 
 namespace Microsoft.CodeAnalysis
 {
@@ -25,7 +28,8 @@ public static implicit operator T(ArrayElement<T> element)
         // as JIT does not know if the write goes to a stack or a heap location.
         // Assigning to Value directly easily avoids all this redundancy.
 
-        public static ArrayElement<T>[] MakeElementArray(T[] items)
+        [return: NotNullIfNotNull(parameterName: "items")]
+        public static ArrayElement<T>[]? MakeElementArray(T[]? items)
         {
             if (items == null)
             {
@@ -41,7 +45,8 @@ public static ArrayElement<T>[] MakeElementArray(T[] items)
             return array;
         }
 
-        public static T[] MakeArray(ArrayElement<T>[] items)
+        [return: NotNullIfNotNull(parameterName: "items")]
+        public static T[]? MakeArray(ArrayElement<T>[]? items)
         {
             if (items == null)
             {

src/Compilers/Core/Portable/Collections/Boxes.cs

@@ -1,5 +1,7 @@
 // Copyright (c) Microsoft.  All Rights Reserved.  Licensed under the Apache License, Version 2.0.  See License.txt in the project root for license information.
 
+#nullable enable
+
 using System;
 
 namespace Microsoft.CodeAnalysis
@@ -21,7 +23,7 @@ internal static class Boxes
         public static readonly object BoxedDoubleZero = 0.0;
         public static readonly object BoxedDecimalZero = 0m;
 
-        private static readonly object[] s_boxedAsciiChars = new object[128];
+        private static readonly object?[] s_boxedAsciiChars = new object?[128];
 
         public static object Box(bool b)
         {

src/Compilers/Core/Portable/Collections/ByteSequenceComparer.cs

@@ -1,9 +1,12 @@
 // Copyright (c) Microsoft.  All Rights Reserved.  Licensed under the Apache License, Version 2.0.  See License.txt in the project root for license information.
 
+#nullable enable
+
 using System;
 using System.Collections.Generic;
 using System.Collections.Immutable;
 using System.Diagnostics;
+using System.Diagnostics.CodeAnalysis;
 using System.Linq;
 using Microsoft.CodeAnalysis.Text;
 using Roslyn.Utilities;
@@ -41,7 +44,7 @@ internal static bool Equals(ImmutableArray<byte> x, ImmutableArray<byte> y)
             return true;
         }
 
-        internal static bool Equals(byte[] left, int leftStart, byte[] right, int rightStart, int length)
+        internal static bool Equals(byte[]? left, int leftStart, byte[]? right, int rightStart, int length)
         {
             if (left == null || right == null)
             {
@@ -64,7 +67,7 @@ internal static bool Equals(byte[] left, int leftStart, byte[] right, int rightS
             return true;
         }
 
-        internal static bool Equals(byte[] left, byte[] right)
+        internal static bool Equals(byte[]? left, byte[]? right)
         {
             if (ReferenceEquals(left, right))
             {
@@ -91,7 +94,7 @@ internal static bool Equals(byte[] left, byte[] right)
 
         internal static int GetHashCode(byte[] x)
         {
-            Debug.Assert(x != null);
+            RoslynDebug.Assert(x != null);
             return Hash.GetFNVHashCode(x);
         }
 
@@ -101,7 +104,7 @@ internal static int GetHashCode(ImmutableArray<byte> x)
             return Hash.GetFNVHashCode(x);
         }
 
-        bool IEqualityComparer<byte[]>.Equals(byte[] x, byte[] y)
+        bool IEqualityComparer<byte[]>.Equals(byte[]? x, byte[]? y)
         {
             return Equals(x, y);
         }

src/Compilers/Core/Portable/Collections/CachingDictionary.cs

@@ -1,10 +1,13 @@
 // Copyright (c) Microsoft.  All Rights Reserved.  Licensed under the Apache License, Version 2.0.  See License.txt in the project root for license information.
 
+#nullable enable
+
 using System;
 using System.Collections.Concurrent;
 using System.Collections.Generic;
 using System.Collections.Immutable;
 using System.Diagnostics;
+using System.Diagnostics.CodeAnalysis;
 using System.Threading;
 using Microsoft.CodeAnalysis.PooledObjects;
 
@@ -25,6 +28,7 @@ namespace Microsoft.CodeAnalysis.Collections
     /// Thread safe.
     /// </summary>
     internal class CachingDictionary<TKey, TElement>
+        where TKey : notnull
     {
         private readonly Func<TKey, ImmutableArray<TElement>> _getElementsOfKey;
         private readonly Func<IEqualityComparer<TKey>, HashSet<TKey>> _getKeys;
@@ -34,7 +38,7 @@ internal class CachingDictionary<TKey, TElement>
         // or something frozen (usually a regular Dictionary). The frozen Dictionary is used only once the collection
         // is fully populated. This is a memory optimization so that we don't hold onto relatively ConcurrentDictionary
         // instances once the cache is fully populated.
-        private IDictionary<TKey, ImmutableArray<TElement>> _map;
+        private IDictionary<TKey, ImmutableArray<TElement>>? _map;
 
         // This is a special sentinel value that is placed inside the map to indicate that a key was looked
         // up, but not found.
@@ -142,7 +146,7 @@ private IDictionary<TKey, ImmutableArray<TElement>> CreateDictionaryForFullyPopu
         private ImmutableArray<TElement> GetOrCreateValue(TKey key)
         {
             ImmutableArray<TElement> elements;
-            ConcurrentDictionary<TKey, ImmutableArray<TElement>> concurrentMap;
+            ConcurrentDictionary<TKey, ImmutableArray<TElement>>? concurrentMap;
 
             // Check if we're fully populated before trying to retrieve the elements.  If we are
             // and we don't get any elements back, then we don't have to go any further.
@@ -197,7 +201,7 @@ private ImmutableArray<TElement> AddToConcurrentMap(ConcurrentDictionary<TKey, I
         /// </summary>
         /// <param name="existingMap">The map to test.</param>
         /// <returns>true if the map is fully populated.</returns>
-        private static bool IsNotFullyPopulatedMap(IDictionary<TKey, ImmutableArray<TElement>> existingMap)
+        private static bool IsNotFullyPopulatedMap([NotNullWhen(returnValue: false)] IDictionary<TKey, ImmutableArray<TElement>>? existingMap)
         {
             return existingMap == null || existingMap is ConcurrentDictionary<TKey, ImmutableArray<TElement>>;
         }
@@ -207,7 +211,7 @@ private static bool IsNotFullyPopulatedMap(IDictionary<TKey, ImmutableArray<TEle
         /// </summary>
         /// <param name="existingMap">The existing map which may be null or a ConcurrentDictionary.</param>
         /// <returns></returns>
-        private IDictionary<TKey, ImmutableArray<TElement>> CreateFullyPopulatedMap(IDictionary<TKey, ImmutableArray<TElement>> existingMap)
+        private IDictionary<TKey, ImmutableArray<TElement>> CreateFullyPopulatedMap(IDictionary<TKey, ImmutableArray<TElement>>? existingMap)
         {
             Debug.Assert(IsNotFullyPopulatedMap(existingMap));
 
@@ -250,7 +254,7 @@ private IDictionary<TKey, ImmutableArray<TElement>> CreateFullyPopulatedMap(IDic
         /// </summary>
         private IDictionary<TKey, ImmutableArray<TElement>> EnsureFullyPopulated()
         {
-            IDictionary<TKey, ImmutableArray<TElement>> fullyPopulatedMap = null;
+            IDictionary<TKey, ImmutableArray<TElement>>? fullyPopulatedMap = null;
 
             var currentMap = _map;
             while (IsNotFullyPopulatedMap(currentMap))

src/Compilers/Core/Portable/Collections/ConsListExtensions.cs

@@ -1,5 +1,7 @@
 // Copyright (c) Microsoft.  All Rights Reserved.  Licensed under the Apache License, Version 2.0.  See License.txt in the project root for license information.
 
+#nullable enable
+
 using Microsoft.CodeAnalysis.Text;
 using Roslyn.Utilities;
 
@@ -10,7 +12,7 @@ namespace Microsoft.CodeAnalysis
     /// </summary>
     internal static class ConsListExtensions
     {
-        public static ConsList<T> Prepend<T>(this ConsList<T> list, T head)
+        public static ConsList<T> Prepend<T>(this ConsList<T>? list, T head)
         {
             return new ConsList<T>(head, list ?? ConsList<T>.Empty);
         }

src/Compilers/Core/Portable/Collections/HashSetExtensions.cs

@@ -1,17 +1,21 @@
 // Copyright (c) Microsoft.  All Rights Reserved.  Licensed under the Apache License, Version 2.0.  See License.txt in the project root for license information.
 
+#nullable enable
+
 using System.Collections.Generic;
+using System.Diagnostics.CodeAnalysis;
 
 namespace Microsoft.CodeAnalysis
 {
     internal static class HashSetExtensions
     {
-        internal static bool IsNullOrEmpty<T>(this HashSet<T> hashSet)
+        internal static bool IsNullOrEmpty<T>([NotNullWhen(returnValue: false)] this HashSet<T>? hashSet)
         {
             return hashSet == null || hashSet.Count == 0;
         }
 
-        internal static bool InitializeAndAdd<T>(ref HashSet<T> hashSet, T item) where T : class
+        internal static bool InitializeAndAdd<T>([NotNullIfNotNull(parameterName: "item"), NotNullWhen(returnValue: true)] ref HashSet<T>? hashSet, [NotNullWhen(returnValue: true)] T? item)
+            where T : class
         {
             if (item is null)
             {

src/Compilers/Core/Portable/Collections/IOrderedReadOnlySet.cs

@@ -1,5 +1,7 @@
 // Copyright (c) Microsoft.  All Rights Reserved.  Licensed under the Apache License, Version 2.0.  See License.txt in the project root for license information.
 
+#nullable enable
+
 using System.Collections.Generic;
 using Roslyn.Utilities;
 

src/Compilers/Core/Portable/Collections/ImmutableArrayExtensions.cs

@@ -1,5 +1,7 @@
 // Copyright (c) Microsoft.  All Rights Reserved.  Licensed under the Apache License, Version 2.0.  See License.txt in the project root for license information.
 
+#nullable enable
+
 using System;
 using System.Collections.Generic;
 using System.Collections.Immutable;
@@ -36,7 +38,7 @@ public static ImmutableArray<T> AsImmutable<T>(this IEnumerable<T> items)
         /// <param name="items">The sequence to convert.</param>
         /// <returns>An immutable copy of the contents of the sequence.</returns>
         /// <remarks>If the sequence is null, this will return an empty array.</remarks>
-        public static ImmutableArray<T> AsImmutableOrEmpty<T>(this IEnumerable<T> items)
+        public static ImmutableArray<T> AsImmutableOrEmpty<T>(this IEnumerable<T>? items)
         {
             if (items == null)
             {
@@ -53,7 +55,7 @@ public static ImmutableArray<T> AsImmutableOrEmpty<T>(this IEnumerable<T> items)
         /// <param name="items">The sequence to convert.</param>
         /// <returns>An immutable copy of the contents of the sequence.</returns>
         /// <remarks>If the sequence is null, this will return the default (null) array.</remarks>
-        public static ImmutableArray<T> AsImmutableOrNull<T>(this IEnumerable<T> items)
+        public static ImmutableArray<T> AsImmutableOrNull<T>(this IEnumerable<T>? items)
         {
             if (items == null)
             {
@@ -82,7 +84,7 @@ public static ImmutableArray<T> AsImmutable<T>(this T[] items)
         /// <param name="items">The sequence to convert</param>
         /// <returns></returns>
         /// <remarks>If the sequence is null, this will return the default (null) array.</remarks>
-        public static ImmutableArray<T> AsImmutableOrNull<T>(this T[] items)
+        public static ImmutableArray<T> AsImmutableOrNull<T>(this T[]? items)
         {
             if (items == null)
             {
@@ -98,7 +100,7 @@ public static ImmutableArray<T> AsImmutableOrNull<T>(this T[] items)
         /// <typeparam name="T"></typeparam>
         /// <param name="items">The sequence to convert</param>
         /// <returns>If the array is null, this will return an empty immutable array.</returns>
-        public static ImmutableArray<T> AsImmutableOrEmpty<T>(this T[] items)
+        public static ImmutableArray<T> AsImmutableOrEmpty<T>(this T[]? items)
         {
             if (items == null)
             {
@@ -260,7 +262,7 @@ public static ImmutableArray<T> WhereAsArray<T>(this ImmutableArray<T> array, Fu
         {
             Debug.Assert(!array.IsDefault);
 
-            ArrayBuilder<T> builder = null;
+            ArrayBuilder<T>? builder = null;
             bool none = true;
             bool all = true;
 
@@ -391,7 +393,7 @@ public static ImmutableArray<T> NullToEmpty<T>(this ImmutableArray<T> array)
         /// Returns an array of distinct elements, preserving the order in the original array.
         /// If the array has no duplicates, the original array is returned. The original array must not be null.
         /// </summary>
-        public static ImmutableArray<T> Distinct<T>(this ImmutableArray<T> array, IEqualityComparer<T> comparer = null)
+        public static ImmutableArray<T> Distinct<T>(this ImmutableArray<T> array, IEqualityComparer<T>? comparer = null)
         {
             Debug.Assert(!array.IsDefault);
 
@@ -448,7 +450,8 @@ internal static ImmutableArray<T> ConditionallyDeOrder<T>(this ImmutableArray<T>
 
         internal static ImmutableArray<TValue> Flatten<TKey, TValue>(
             this Dictionary<TKey, ImmutableArray<TValue>> dictionary,
-            IComparer<TValue> comparer = null)
+            IComparer<TValue>? comparer = null)
+            where TKey : notnull
         {
             if (dictionary.Count == 0)
             {
@@ -525,7 +528,7 @@ public static int Count<T>(this ImmutableArray<T> items, Func<T, bool> predicate
             return count;
         }
 
-        internal static Dictionary<K, ImmutableArray<T>> ToDictionary<K, T>(this ImmutableArray<T> items, Func<T, K> keySelector, IEqualityComparer<K> comparer = null)
+        internal static Dictionary<K, ImmutableArray<T>> ToDictionary<K, T>(this ImmutableArray<T> items, Func<T, K> keySelector, IEqualityComparer<K>? comparer = null)
         {
             if (items.Length == 1)
             {