Augment several "bool IsXx" APIs with [NotNullWhen(true)] (#1372)

If these methods return true, we know the argument passed in wasn't null. Annotating it as such can help reduce warnings in callers.
dotnet · Jan 8, 2020 · 25ea6c4 · 25ea6c4
1 parent 7c24ebc
commit 25ea6c4
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Showing 22 changed files with 60 additions and 46 deletions.
diff --git a/src/coreclr/src/System.Private.CoreLib/src/System/Reflection/Emit/EnumBuilder.cs b/src/coreclr/src/System.Private.CoreLib/src/System/Reflection/Emit/EnumBuilder.cs
@@ -13,13 +13,14 @@
 **
 ===========================================================*/
 
+using System.Diagnostics.CodeAnalysis;
 using CultureInfo = System.Globalization.CultureInfo;
 
 namespace System.Reflection.Emit
 {
     public sealed class EnumBuilder : TypeInfo
     {
-        public override bool IsAssignableFrom(TypeInfo? typeInfo)
+        public override bool IsAssignableFrom([NotNullWhen(true)] TypeInfo? typeInfo)
         {
             if (typeInfo == null) return false;
             return IsAssignableFrom(typeInfo.AsType());

diff --git a/...eclr/src/System.Private.CoreLib/src/System/Reflection/Emit/GenericTypeParameterBuilder.cs b/...eclr/src/System.Private.CoreLib/src/System/Reflection/Emit/GenericTypeParameterBuilder.cs
@@ -2,13 +2,14 @@
 // 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.Diagnostics.CodeAnalysis;
 using System.Globalization;
 
 namespace System.Reflection.Emit
 {
     public sealed class GenericTypeParameterBuilder : TypeInfo
     {
-        public override bool IsAssignableFrom(System.Reflection.TypeInfo? typeInfo)
+        public override bool IsAssignableFrom([NotNullWhen(true)] TypeInfo? typeInfo)
         {
             if (typeInfo == null) return false;
             return IsAssignableFrom(typeInfo.AsType());
@@ -176,7 +177,7 @@ public override Type MakeArrayType(int rank)
 
         protected override bool IsValueTypeImpl() { return false; }
 
-        public override bool IsAssignableFrom(Type? c) { throw new NotSupportedException(); }
+        public override bool IsAssignableFrom([NotNullWhen(true)] Type? c) { throw new NotSupportedException(); }
 
         public override bool IsSubclassOf(Type c) { throw new NotSupportedException(); }
         #endregion

diff --git a/src/coreclr/src/System.Private.CoreLib/src/System/Reflection/Emit/SymbolType.cs b/src/coreclr/src/System.Private.CoreLib/src/System/Reflection/Emit/SymbolType.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.
 
+using System.Diagnostics.CodeAnalysis;
 using CultureInfo = System.Globalization.CultureInfo;
 
 namespace System.Reflection.Emit
@@ -16,7 +17,7 @@ internal enum TypeKind
     // This is a kind of Type object that will represent the compound expression of a parameter type or field type.
     internal sealed class SymbolType : TypeInfo
     {
-        public override bool IsAssignableFrom(TypeInfo? typeInfo)
+        public override bool IsAssignableFrom([NotNullWhen(true)] TypeInfo? typeInfo)
         {
             if (typeInfo == null) return false;
             return IsAssignableFrom(typeInfo.AsType());

diff --git a/src/coreclr/src/System.Private.CoreLib/src/System/Reflection/Emit/TypeBuilder.cs b/src/coreclr/src/System.Private.CoreLib/src/System/Reflection/Emit/TypeBuilder.cs
@@ -4,6 +4,7 @@
 
 using System.Collections.Generic;
 using System.Diagnostics;
+using System.Diagnostics.CodeAnalysis;
 using System.Runtime.InteropServices;
 using System.Runtime.CompilerServices;
 using CultureInfo = System.Globalization.CultureInfo;
@@ -12,7 +13,7 @@ namespace System.Reflection.Emit
 {
     public sealed class TypeBuilder : TypeInfo
     {
-        public override bool IsAssignableFrom(TypeInfo? typeInfo)
+        public override bool IsAssignableFrom([NotNullWhen(true)] TypeInfo? typeInfo)
         {
             if (typeInfo == null) return false;
             return IsAssignableFrom(typeInfo.AsType());
@@ -915,7 +916,7 @@ public override MemberInfo[] GetMembers(BindingFlags bindingAttr)
             return m_bakedRuntimeType.GetMembers(bindingAttr);
         }
 
-        public override bool IsAssignableFrom(Type? c)
+        public override bool IsAssignableFrom([NotNullWhen(true)] Type? c)
         {
             if (IsTypeEqual(c, this))
                 return true;

diff --git a/...coreclr/src/System.Private.CoreLib/src/System/Reflection/Emit/TypeBuilderInstantiation.cs b/...coreclr/src/System.Private.CoreLib/src/System/Reflection/Emit/TypeBuilderInstantiation.cs
@@ -5,12 +5,13 @@
 using System.Collections;
 using System.Globalization;
 using System.Diagnostics;
+using System.Diagnostics.CodeAnalysis;
 
 namespace System.Reflection.Emit
 {
     internal sealed class TypeBuilderInstantiation : TypeInfo
     {
-        public override bool IsAssignableFrom(System.Reflection.TypeInfo? typeInfo)
+        public override bool IsAssignableFrom([NotNullWhen(true)] TypeInfo? typeInfo)
         {
             if (typeInfo == null) return false;
             return IsAssignableFrom(typeInfo.AsType());
@@ -208,7 +209,7 @@ public override bool ContainsGenericParameters
         public override MethodBase? DeclaringMethod => null;
         public override Type GetGenericTypeDefinition() { return m_type; }
         public override Type MakeGenericType(params Type[] inst) { throw new InvalidOperationException(SR.Format(SR.Arg_NotGenericTypeDefinition, this)); }
-        public override bool IsAssignableFrom(Type? c) { throw new NotSupportedException(); }
+        public override bool IsAssignableFrom([NotNullWhen(true)] Type? c) { throw new NotSupportedException(); }
 
         public override bool IsSubclassOf(Type c)
         {

diff --git a/src/coreclr/src/System.Private.CoreLib/src/System/RuntimeHandles.cs b/src/coreclr/src/System.Private.CoreLib/src/System/RuntimeHandles.cs
@@ -3,6 +3,7 @@
 // See the LICENSE file in the project root for more information.
 
 using System.Diagnostics;
+using System.Diagnostics.CodeAnalysis;
 using System.Reflection;
 using System.Runtime.CompilerServices;
 using System.Runtime.InteropServices;
@@ -35,7 +36,7 @@ internal RuntimeType GetTypeChecked()
         }
 
         [MethodImpl(MethodImplOptions.InternalCall)]
-        internal static extern bool IsInstanceOfType(RuntimeType type, object? o);
+        internal static extern bool IsInstanceOfType(RuntimeType type, [NotNullWhen(true)] object? o);
 
         internal static Type GetTypeHelper(Type typeStart, Type[]? genericArgs, IntPtr pModifiers, int cModifiers)
         {

diff --git a/src/coreclr/src/System.Private.CoreLib/src/System/RuntimeType.CoreCLR.cs b/src/coreclr/src/System.Private.CoreLib/src/System/RuntimeType.CoreCLR.cs
@@ -5,16 +5,16 @@
 using System.Collections;
 using System.Collections.Generic;
 using System.Diagnostics;
+using System.Diagnostics.CodeAnalysis;
 using System.Globalization;
 using System.Reflection;
 using System.Runtime.CompilerServices;
 using System.Runtime.InteropServices;
 using System.Text;
 using System.Threading;
+using Internal.Runtime.CompilerServices;
 using DebuggerStepThroughAttribute = System.Diagnostics.DebuggerStepThroughAttribute;
 using MdToken = System.Reflection.MetadataToken;
-using Internal.Runtime.CompilerServices;
-using System.Diagnostics.CodeAnalysis;
 
 namespace System
 {
@@ -3082,7 +3082,7 @@ public override bool IsSubclassOf(Type type)
 
 #if FEATURE_TYPEEQUIVALENCE
         // Reflexive, symmetric, transitive.
-        public override bool IsEquivalentTo(Type? other)
+        public override bool IsEquivalentTo([NotNullWhen(true)] Type? other)
         {
             if (!(other is RuntimeType otherRtType))
             {

diff --git a/src/libraries/System.Private.CoreLib/src/System/Convert.cs b/src/libraries/System.Private.CoreLib/src/System/Convert.cs
@@ -2,11 +2,11 @@
 // 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.Diagnostics;
+using System.Diagnostics.CodeAnalysis;
 using System.Globalization;
 using System.Runtime.CompilerServices;
 using System.Runtime.InteropServices;
-using System.Diagnostics;
-using System.Diagnostics.CodeAnalysis;
 
 namespace System
 {
@@ -163,7 +163,7 @@ public static TypeCode GetTypeCode(object? value)
 
         // Returns true if the given object is a database null. This operation
         // corresponds to "value.GetTypeCode() == TypeCode.DBNull".
-        public static bool IsDBNull(object? value)
+        public static bool IsDBNull([NotNullWhen(true)] object? value)
         {
             if (value == System.DBNull.Value) return true;
             return value is IConvertible convertible ? convertible.GetTypeCode() == TypeCode.DBNull : false;

diff --git a/src/libraries/System.Private.CoreLib/src/System/IO/Path.Unix.cs b/src/libraries/System.Private.CoreLib/src/System/IO/Path.Unix.cs
@@ -3,6 +3,7 @@
 // See the LICENSE file in the project root for more information.
 
 using System.Diagnostics;
+using System.Diagnostics.CodeAnalysis;
 using System.Runtime.InteropServices;
 using System.Text;
 
@@ -103,7 +104,7 @@ public static string GetTempFileName()
             return Encoding.UTF8.GetString(name, 0, name.Length - 1); // trim off the trailing '\0'
         }
 
-        public static bool IsPathRooted(string? path)
+        public static bool IsPathRooted([NotNullWhen(true)] string? path)
         {
             if (path == null)
                 return false;

diff --git a/src/libraries/System.Private.CoreLib/src/System/IO/Path.Windows.cs b/src/libraries/System.Private.CoreLib/src/System/IO/Path.Windows.cs
@@ -4,6 +4,7 @@
 
 #nullable enable
 using System.Diagnostics;
+using System.Diagnostics.CodeAnalysis;
 using System.Text;
 
 #if MS_IO_REDIST
@@ -187,7 +188,7 @@ public static string GetTempFileName()
 
         // Tests if the given path contains a root. A path is considered rooted
         // if it starts with a backslash ("\") or a valid drive letter and a colon (":").
-        public static bool IsPathRooted(string? path)
+        public static bool IsPathRooted([NotNullWhen(true)] string? path)
         {
             return path != null && IsPathRooted(path.AsSpan());
         }

diff --git a/src/libraries/System.Private.CoreLib/src/System/Reflection/SignatureType.cs b/src/libraries/System.Private.CoreLib/src/System/Reflection/SignatureType.cs
@@ -2,8 +2,9 @@
 // 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.Globalization;
 using System.Collections.Generic;
+using System.Diagnostics.CodeAnalysis;
+using System.Globalization;
 using System.Runtime.InteropServices;
 
 namespace System.Reflection
@@ -80,7 +81,7 @@ public sealed override Type MakeArrayType(int rank)
         public sealed override Type BaseType => throw new NotSupportedException(SR.NotSupported_SignatureType);
 
         public sealed override Type[] GetInterfaces() => throw new NotSupportedException(SR.NotSupported_SignatureType);
-        public sealed override bool IsAssignableFrom(Type? c) => throw new NotSupportedException(SR.NotSupported_SignatureType);
+        public sealed override bool IsAssignableFrom([NotNullWhen(true)] Type? c) => throw new NotSupportedException(SR.NotSupported_SignatureType);
         public sealed override int MetadataToken => throw new NotSupportedException(SR.NotSupported_SignatureType);
         public sealed override bool HasSameMetadataDefinitionAs(MemberInfo other) => throw new NotSupportedException(SR.NotSupported_SignatureType);
 
@@ -129,8 +130,8 @@ public sealed override Type MakeArrayType(int rank)
         public sealed override InterfaceMapping GetInterfaceMap(Type interfaceType) => throw new NotSupportedException(SR.NotSupported_SignatureType);
         protected sealed override bool IsContextfulImpl() => throw new NotSupportedException(SR.NotSupported_SignatureType);
         public sealed override bool IsEnum => throw new NotSupportedException(SR.NotSupported_SignatureType);
-        public sealed override bool IsEquivalentTo(Type? other) => throw new NotSupportedException(SR.NotSupported_SignatureType);
-        public sealed override bool IsInstanceOfType(object? o) => throw new NotSupportedException(SR.NotSupported_SignatureType);
+        public sealed override bool IsEquivalentTo([NotNullWhen(true)] Type? other) => throw new NotSupportedException(SR.NotSupported_SignatureType);
+        public sealed override bool IsInstanceOfType([NotNullWhen(true)] object? o) => throw new NotSupportedException(SR.NotSupported_SignatureType);
         protected sealed override bool IsMarshalByRefImpl() => throw new NotSupportedException(SR.NotSupported_SignatureType);
         public sealed override bool IsSecurityCritical => throw new NotSupportedException(SR.NotSupported_SignatureType);
         public sealed override bool IsSecuritySafeCritical => throw new NotSupportedException(SR.NotSupported_SignatureType);

diff --git a/src/libraries/System.Private.CoreLib/src/System/Reflection/TypeDelegator.cs b/src/libraries/System.Private.CoreLib/src/System/Reflection/TypeDelegator.cs
@@ -6,13 +6,14 @@
 //
 // This class wraps a Type object and delegates all methods to that Type.
 
+using System.Diagnostics.CodeAnalysis;
 using CultureInfo = System.Globalization.CultureInfo;
 
 namespace System.Reflection
 {
     public class TypeDelegator : TypeInfo
     {
-        public override bool IsAssignableFrom(TypeInfo? typeInfo)
+        public override bool IsAssignableFrom([NotNullWhen(true)] TypeInfo? typeInfo)
         {
             if (typeInfo == null)
                 return false;

diff --git a/src/libraries/System.Private.CoreLib/src/System/Reflection/TypeInfo.cs b/src/libraries/System.Private.CoreLib/src/System/Reflection/TypeInfo.cs
@@ -3,6 +3,7 @@
 // See the LICENSE file in the project root for more information.
 
 using System.Collections.Generic;
+using System.Diagnostics.CodeAnalysis;
 
 namespace System.Reflection
 {
@@ -50,7 +51,7 @@ public virtual IEnumerable<System.Reflection.TypeInfo> DeclaredNestedTypes
         public virtual IEnumerable<Type> ImplementedInterfaces => GetInterfaces();
 
         // a re-implementation of ISAF from Type, skipping the use of UnderlyingType
-        public virtual bool IsAssignableFrom(TypeInfo? typeInfo)
+        public virtual bool IsAssignableFrom([NotNullWhen(true)] TypeInfo? typeInfo)
         {
             if (typeInfo == null)
                 return false;

diff --git a/src/libraries/System.Private.CoreLib/src/System/RuntimeType.cs b/src/libraries/System.Private.CoreLib/src/System/RuntimeType.cs
@@ -3,6 +3,7 @@
 // See the LICENSE file in the project root for more information.
 
 using System.Collections.Generic;
+using System.Diagnostics.CodeAnalysis;
 using System.Reflection;
 using System.Runtime.CompilerServices;
 
@@ -293,17 +294,17 @@ protected override bool IsValueTypeImpl()
 
         protected override bool IsCOMObjectImpl() => RuntimeTypeHandle.IsComObject(this, false);
 
-        public override bool IsInstanceOfType(object? o) => RuntimeTypeHandle.IsInstanceOfType(this, o);
+        public override bool IsInstanceOfType([NotNullWhen(true)] object? o) => RuntimeTypeHandle.IsInstanceOfType(this, o);
 
-        public override bool IsAssignableFrom(TypeInfo? typeInfo)
+        public override bool IsAssignableFrom([NotNullWhen(true)] TypeInfo? typeInfo)
         {
             if (typeInfo == null)
                 return false;
 
             return IsAssignableFrom(typeInfo.AsType());
         }
 
-        public override bool IsAssignableFrom(Type? c)
+        public override bool IsAssignableFrom([NotNullWhen(true)] Type? c)
         {
             if (c is null)
                 return false;

diff --git a/src/libraries/System.Private.CoreLib/src/System/Type.Helpers.cs b/src/libraries/System.Private.CoreLib/src/System/Type.Helpers.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.
 
+using System.Diagnostics.CodeAnalysis;
 using System.Reflection;
 
 namespace System
@@ -330,7 +331,7 @@ public virtual bool IsSubclassOf(Type c)
             return false;
         }
 
-        public virtual bool IsAssignableFrom(Type? c)
+        public virtual bool IsAssignableFrom([NotNullWhen(true)] Type? c)
         {
             if (c == null)
                 return false;

diff --git a/src/libraries/System.Private.CoreLib/src/System/Type.cs b/src/libraries/System.Private.CoreLib/src/System/Type.cs
@@ -2,12 +2,13 @@
 // 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.Threading;
-using System.Reflection;
 using System.Diagnostics;
+using System.Diagnostics.CodeAnalysis;
 using System.Globalization;
+using System.Reflection;
 using System.Runtime.CompilerServices;
 using System.Runtime.InteropServices;
+using System.Threading;
 
 namespace System
 {
@@ -314,8 +315,8 @@ protected virtual TypeCode GetTypeCodeImpl()
 
         public virtual InterfaceMapping GetInterfaceMap(Type interfaceType) => throw new NotSupportedException(SR.NotSupported_SubclassOverride);
 
-        public virtual bool IsInstanceOfType(object? o) => o == null ? false : IsAssignableFrom(o.GetType());
-        public virtual bool IsEquivalentTo(Type? other) => this == other;
+        public virtual bool IsInstanceOfType([NotNullWhen(true)] object? o) => o == null ? false : IsAssignableFrom(o.GetType());
+        public virtual bool IsEquivalentTo([NotNullWhen(true)] Type? other) => this == other;
 
         public virtual Type GetEnumUnderlyingType()
         {

diff --git a/src/libraries/System.Private.Uri/src/System/UriExt.cs b/src/libraries/System.Private.Uri/src/System/UriExt.cs
@@ -383,7 +383,7 @@ public bool IsWellFormedOriginalString()
             return Syntax.InternalIsWellFormedOriginalString(this);
         }
 
-        public static bool IsWellFormedUriString(string? uriString, UriKind uriKind)
+        public static bool IsWellFormedUriString([NotNullWhen(true)] string? uriString, UriKind uriKind)
         {
             Uri? result;
 

diff --git a/src/libraries/System.Reflection.Emit/ref/System.Reflection.Emit.cs b/src/libraries/System.Reflection.Emit/ref/System.Reflection.Emit.cs
@@ -220,7 +220,7 @@ public sealed partial class GenericTypeParameterBuilder : System.Type
         protected override bool HasElementTypeImpl() { throw null; }
         public override object InvokeMember(string name, System.Reflection.BindingFlags invokeAttr, System.Reflection.Binder? binder, object? target, object?[]? args, System.Reflection.ParameterModifier[]? modifiers, System.Globalization.CultureInfo? culture, string[]? namedParameters) { throw null; }
         protected override bool IsArrayImpl() { throw null; }
-        public override bool IsAssignableFrom(System.Type? c) { throw null; }
+        public override bool IsAssignableFrom([System.Diagnostics.CodeAnalysis.NotNullWhen(true)] System.Type? c) { throw null; }
         protected override bool IsByRefImpl() { throw null; }
         protected override bool IsCOMObjectImpl() { throw null; }
         public override bool IsDefined(System.Type attributeType, bool inherit) { throw null; }
@@ -449,7 +449,7 @@ public sealed partial class TypeBuilder : System.Type
         protected override bool HasElementTypeImpl() { throw null; }
         public override object? InvokeMember(string name, System.Reflection.BindingFlags invokeAttr, System.Reflection.Binder? binder, object? target, object?[]? args, System.Reflection.ParameterModifier[]? modifiers, System.Globalization.CultureInfo? culture, string[]? namedParameters) { throw null; }
         protected override bool IsArrayImpl() { throw null; }
-        public override bool IsAssignableFrom(System.Type? c) { throw null; }
+        public override bool IsAssignableFrom([System.Diagnostics.CodeAnalysis.NotNullWhen(true)] System.Type? c) { throw null; }
         protected override bool IsByRefImpl() { throw null; }
         protected override bool IsCOMObjectImpl() { throw null; }
         public bool IsCreated() { throw null; }

diff --git a/src/libraries/System.Reflection.TypeExtensions/ref/System.Reflection.TypeExtensions.cs b/src/libraries/System.Reflection.TypeExtensions/ref/System.Reflection.TypeExtensions.cs
@@ -78,7 +78,7 @@ public static partial class TypeExtensions
         public static System.Reflection.PropertyInfo? GetProperty(this System.Type type, string name, System.Reflection.BindingFlags bindingAttr) { throw null; }
         public static System.Reflection.PropertyInfo? GetProperty(this System.Type type, string name, System.Type? returnType) { throw null; }
         public static System.Reflection.PropertyInfo? GetProperty(this System.Type type, string name, System.Type? returnType, System.Type[] types) { throw null; }
-        public static bool IsAssignableFrom(this System.Type type, System.Type? c) { throw null; }
-        public static bool IsInstanceOfType(this System.Type type, object? o) { throw null; }
+        public static bool IsAssignableFrom(this System.Type type, [System.Diagnostics.CodeAnalysis.NotNullWhen(true)] System.Type? c) { throw null; }
+        public static bool IsInstanceOfType(this System.Type type, [System.Diagnostics.CodeAnalysis.NotNullWhen(true)] object? o) { throw null; }
     }
 }
diff --git a/src/libraries/System.Reflection.TypeExtensions/src/System/Reflection/TypeExtensions.cs b/src/libraries/System.Reflection.TypeExtensions/src/System/Reflection/TypeExtensions.cs
@@ -201,13 +201,13 @@ public static PropertyInfo[] GetProperties(Type type, BindingFlags bindingAttr)
             return type.GetProperty(name, returnType, types);
         }
 
-        public static bool IsAssignableFrom(Type type, Type? c)
+        public static bool IsAssignableFrom(Type type, [System.Diagnostics.CodeAnalysis.NotNullWhen(true)] Type? c)
         {
             Requires.NotNull(type, nameof(type));
             return type.IsAssignableFrom(c);
         }
 
-        public static bool IsInstanceOfType(Type type, object? o)
+        public static bool IsInstanceOfType(Type type, [System.Diagnostics.CodeAnalysis.NotNullWhen(true)] object? o)
         {
             Requires.NotNull(type, nameof(type));
             return type.IsInstanceOfType(o);