Match Attributes for virtual methods and overrides

docs/error-codes.md

@@ -782,10 +782,13 @@ This is technically possible if a custom assembly defines `DynamicDependencyAttr
   }
   ```
 
-#### `IL2046` Trim analysis: Presence of 'RequiresUnreferencedCodeAttribute' on method 'method' doesn't match overridden method 'base method'. All overridden methods must have 'RequiresUnreferencedCodeAttribute'.
+#### `IL2046`: Trim analysis: Member 'member' with 'RequiresUnreferencedCodeAttribute' has a member 'member' without 'RequiresUnreferencedCodeAttribute'. For all interfaces and overrides the implementation attribute must match the definition attribute.
 
-- All overrides of a virtual method including the base method must either have or not have the `RequiresUnreferencedCodeAttribute`.
+- For all interfaces and overrides the implementation 'RequiresUnreferencedCodeAttribute' must match the definition 'RequiresUnreferecedCodeAttribute', either all the members contain the attribute o none of them.
 
+  Here is a list of posible scenarios where the warning can be generated:
+
+  A base member has the attribute but the derived member does not have the attribute
   ```C#
   public class Base
   {
@@ -795,10 +798,53 @@ This is technically possible if a custom assembly defines `DynamicDependencyAttr
 
   public class Derived : Base
   {
-    // IL2046: Presence of 'RequiresUnreferencedCodeAttribute' on method 'Derived.TestMethod()' doesn't match overridden method 'Base.TestMethod'. All overridden methods must have 'RequiresUnreferencedCodeAttribute'.
+    // IL2046: Base member 'Base.TestMethod' with 'RequiresUnreferencedCodeAttribute' has a derived member 'Derived.TestMethod()' without 'RequiresUnreferencedCodeAttribute'. For all interfaces and overrides the implementation attribute must match the definition attribute.
+    public override void TestMethod() {}
+  }
+  ```
+  A derived member has the attribute but the overriden base member does not have the attribute
+  ```C#
+  public class Base
+  {
+    public virtual void TestMethod() {}
+  }
+
+  public class Derived : Base
+  {
+    // IL2046: Member 'Derived.TestMethod()' with 'RequiresUnreferencedCodeAttribute' overrides base member 'Base.TestMethod()' without 'RequiresUnreferencedCodeAttribute'. For all interfaces and overrides the implementation attribute must match the definition attribute.
+    [RequireUnreferencedCode("Message")]
     public override void TestMethod() {}
   }
   ```
+  An interface member has the attribute but it's implementation does not have the attribute
+  ```C#
+  interface IRUC
+  {
+    [RequiresUnreferencedCode("Message")]
+    void TestMethod();
+  }
+
+  class Implementation : IRUC
+  {
+    // IL2046: Interface member 'IRUC.TestMethod()' with 'RequiresUnreferencedCodeAttribute' has an implementation member 'Implementation.TestMethod()' without 'RequiresUnreferencedCodeAttribute'. For all interfaces and overrides the implementation attribute must match the definition attribute.
+    public void TestMethod () { }
+  }
+  ```
+  An implementation member has the attribute but the interface that implementes does not have the attribute
+
+  ```C#
+  interface IRUC
+  {
+    void TestMethod();
+  }
+
+  class Implementation : IRUC
+  {
+    [RequiresUnreferencedCode("Message")]
+    // IL2046: Member 'Implementation.TestMethod()' with 'RequiresUnreferencedCodeAttribute' implements interface member 'IRUC.TestMethod()' without 'RequiresUnreferencedCodeAttribute'. For all interfaces and overrides the implementation attribute must match the definition attribute.
+    public void TestMethod () { }
+  }
+  ```
 
 #### `IL2048`: Internal attribute 'RemoveAttributeInstances' can only be used on a type, but is being used on 'member'
 
@@ -1682,3 +1728,67 @@ class Test
       MethodWithAssemblyFilesUsage();
   }
   ```
+
+#### `IL3003`: Member 'member' with 'RequiresAssemblyFilesAttribute' has a member 'member' without 'RequiresAssemblyFilesAttribute'. For all interfaces and overrides the implementation attribute must match the definition attribute.
+
+- For all interfaces and overrides the implementation 'RequiresAssemblyFilesAttribute' must match the definition 'RequiresAssemblyFilesAttribute', either all the members contain the attribute o none of them.
+
+  Here is a list of posible scenarios where the warning can be generated:
+
+  A base member has the attribute but the derived member does not have the attribute
+  ```C#
+  public class Base
+  {
+    [RequiresAssemblyFiles]
+    public virtual void TestMethod() {}
+  }
+
+  public class Derived : Base
+  {
+    // IL3003: Base member 'Base.TestMethod' with 'RequiresAssemblyFilesAttribute' has a derived member 'Derived.TestMethod()' without 'RequiresAssemblyFilesAttribute'. For all interfaces and overrides the implementation attribute must match the definition attribute.
+    public override void TestMethod() {}
+  }
+  ```
+  A derived member has the attribute but the overriden base member does not have the attribute
+  ```C#
+  public class Base
+  {
+    public virtual void TestMethod() {}
+  }
+
+  public class Derived : Base
+  {
+    // IL3003: Member 'Derived.TestMethod()' with 'RequiresAssemblyFilesAttribute' overrides base member 'Base.TestMethod()' without 'RequiresAssemblyFilesAttribute'. For all interfaces and overrides the implementation attribute must match the definition attribute.
+    [RequiresAssemblyFiles]
+    public override void TestMethod() {}
+  }
+  ```
+  An interface member has the attribute but it's implementation does not have the attribute
+  ```C#
+  interface IRAF
+  {
+    [RequiresAssemblyFiles]
+    void TestMethod();
+  }
+
+  class Implementation : IRAF
+  {
+    // IL3003: Interface member 'IRAF.TestMethod()' with 'RequiresAssemblyFilesAttribute' has an implementation member 'Implementation.TestMethod()' without 'RequiresAssemblyFilesAttribute'. For all interfaces and overrides the implementation attribute must match the definition attribute.
+    public void TestMethod () { }
+  }
+  ```
+  An implementation member has the attribute but the interface that implementes does not have the attribute
+
+  ```C#
+  interface IRAF
+  {
+    void TestMethod();
+  }
+
+  class Implementation : IRAF
+  {
+    [RequiresAssemblyFiles]
+    // IL3003: Member 'Implementation.TestMethod()' with 'RequiresAssemblyFilesAttribute' implements interface member 'IRAF.TestMethod()' without 'RequiresAssemblyFilesAttribute'. For all interfaces and overrides the implementation attribute must match the definition attribute.
+    public void TestMethod () { }
+  }
+  ```

src/ILLink.RoslynAnalyzer/ILLink.RoslynAnalyzer.csproj

@@ -18,7 +18,10 @@
 
   <!-- Shared files with the linker -->
   <ItemGroup>
-    <EmbeddedResource Include="../ILLink.Shared/SharedStrings.resx" GenerateSource="true" />
+    <EmbeddedResource Include="../ILLink.Shared/SharedStrings.resx">
+      <GenerateSource>true</GenerateSource>
+      <Namespace>ILLink.Shared</Namespace>
+    </EmbeddedResource>
     <Compile Include="../ILLink.Shared/**/*.cs" />
   </ItemGroup>
 

src/ILLink.RoslynAnalyzer/ISymbolExtensions.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.Text;
 using Microsoft.CodeAnalysis;
 
@@ -21,6 +22,17 @@ internal static bool HasAttribute (this ISymbol symbol, string attributeName)
 			return false;
 		}
 
+		internal static bool TryGetOverriddenMember (this ISymbol? symbol, [NotNullWhen (returnValue: true)] out ISymbol? overridenMember)
+		{
+			overridenMember = symbol switch {
+				IMethodSymbol method => method.OverriddenMethod,
+				IPropertySymbol property => property.OverriddenProperty,
+				IEventSymbol @event => @event.OverriddenEvent,
+				_ => null,
+			};
+			return overridenMember != null;
+		}
+
 		public static string GetDisplayName (this ISymbol symbol)
 		{
 			var sb = new StringBuilder ();

src/ILLink.RoslynAnalyzer/NullableAttributes.cs

@@ -0,0 +1,150 @@
+// Licensed to the .NET Foundation under one or more agreements.
+// The .NET Foundation licenses this file to you under the MIT license.
+// See the LICENSE file in the project root for more information.
+
+// This was copied from https://github.com/dotnet/runtime/blob/39b9607807f29e48cae4652cd74735182b31182e/src/libraries/System.Private.CoreLib/src/System/Diagnostics/CodeAnalysis/NullableAttributes.cs
+// and updated to have the scope of the attributes be internal.
+namespace System.Diagnostics.CodeAnalysis
+{
+#if !NETCOREAPP
+
+	/// <summary>Specifies that null is allowed as an input even if the corresponding type disallows it.</summary>
+	[AttributeUsage (AttributeTargets.Field | AttributeTargets.Parameter | AttributeTargets.Property, Inherited = false)]
+	internal sealed class AllowNullAttribute : Attribute { }
+
+	/// <summary>Specifies that null is disallowed as an input even if the corresponding type allows it.</summary>
+	[AttributeUsage (AttributeTargets.Field | AttributeTargets.Parameter | AttributeTargets.Property, Inherited = false)]
+	internal sealed class DisallowNullAttribute : Attribute { }
+
+	/// <summary>Specifies that an output may be null even if the corresponding type disallows it.</summary>
+	[AttributeUsage (AttributeTargets.Field | AttributeTargets.Parameter | AttributeTargets.Property | AttributeTargets.ReturnValue, Inherited = false)]
+	internal sealed class MaybeNullAttribute : Attribute { }
+
+	/// <summary>Specifies that an output will not be null even if the corresponding type allows it.</summary>
+	[AttributeUsage (AttributeTargets.Field | AttributeTargets.Parameter | AttributeTargets.Property | AttributeTargets.ReturnValue, Inherited = false)]
+	internal sealed class NotNullAttribute : Attribute { }
+
+	/// <summary>Specifies that when a method returns <see cref="ReturnValue"/>, the parameter may be null even if the corresponding type disallows it.</summary>
+	[AttributeUsage (AttributeTargets.Parameter, Inherited = false)]
+	internal sealed class MaybeNullWhenAttribute : Attribute
+	{
+		/// <summary>Initializes the attribute with the specified return value condition.</summary>
+		/// <param name="returnValue">
+		/// The return value condition. If the method returns this value, the associated parameter may be null.
+		/// </param>
+		public MaybeNullWhenAttribute (bool returnValue) => ReturnValue = returnValue;
+
+		/// <summary>Gets the return value condition.</summary>
+		public bool ReturnValue { get; }
+	}
+
+	/// <summary>Specifies that when a method returns <see cref="ReturnValue"/>, the parameter will not be null even if the corresponding type allows it.</summary>
+	[AttributeUsage (AttributeTargets.Parameter, Inherited = false)]
+	internal sealed class NotNullWhenAttribute : Attribute
+	{
+		/// <summary>Initializes the attribute with the specified return value condition.</summary>
+		/// <param name="returnValue">
+		/// The return value condition. If the method returns this value, the associated parameter will not be null.
+		/// </param>
+		public NotNullWhenAttribute (bool returnValue) => ReturnValue = returnValue;
+
+		/// <summary>Gets the return value condition.</summary>
+		public bool ReturnValue { get; }
+	}
+
+	/// <summary>Specifies that the output will be non-null if the named parameter is non-null.</summary>
+	[AttributeUsage (AttributeTargets.Parameter | AttributeTargets.Property | AttributeTargets.ReturnValue, AllowMultiple = true, Inherited = false)]
+	internal sealed class NotNullIfNotNullAttribute : Attribute
+	{
+		/// <summary>Initializes the attribute with the associated parameter name.</summary>
+		/// <param name="parameterName">
+		/// The associated parameter name.  The output will be non-null if the argument to the parameter specified is non-null.
+		/// </param>
+		public NotNullIfNotNullAttribute (string parameterName) => ParameterName = parameterName;
+
+		/// <summary>Gets the associated parameter name.</summary>
+		public string ParameterName { get; }
+	}
+
+	/// <summary>Applied to a method that will never return under any circumstance.</summary>
+	[AttributeUsage (AttributeTargets.Method, Inherited = false)]
+	internal sealed class DoesNotReturnAttribute : Attribute { }
+
+	/// <summary>Specifies that the method will not return if the associated Boolean parameter is passed the specified value.</summary>
+	[AttributeUsage (AttributeTargets.Parameter, Inherited = false)]
+	internal sealed class DoesNotReturnIfAttribute : Attribute
+	{
+		/// <summary>Initializes the attribute with the specified parameter value.</summary>
+		/// <param name="parameterValue">
+		/// The condition parameter value. Code after the method will be considered unreachable by diagnostics if the argument to
+		/// the associated parameter matches this value.
+		/// </param>
+		public DoesNotReturnIfAttribute (bool parameterValue) => ParameterValue = parameterValue;
+
+		/// <summary>Gets the condition parameter value.</summary>
+		public bool ParameterValue { get; }
+	}
+
+#endif
+
+#if !NETCOREAPP || NETCOREAPP3_1
+
+	/// <summary>Specifies that the method or property will ensure that the listed field and property members have not-null values.</summary>
+	[AttributeUsage (AttributeTargets.Method | AttributeTargets.Property, Inherited = false, AllowMultiple = true)]
+	internal sealed class MemberNotNullAttribute : Attribute
+	{
+		/// <summary>Initializes the attribute with a field or property member.</summary>
+		/// <param name="member">
+		/// The field or property member that is promised to be not-null.
+		/// </param>
+		public MemberNotNullAttribute (string member) => Members = new[] { member };
+
+		/// <summary>Initializes the attribute with the list of field and property members.</summary>
+		/// <param name="members">
+		/// The list of field and property members that are promised to be not-null.
+		/// </param>
+		public MemberNotNullAttribute (params string[] members) => Members = members;
+
+		/// <summary>Gets field or property member names.</summary>
+		public string[] Members { get; }
+	}
+
+	/// <summary>Specifies that the method or property will ensure that the listed field and property members have not-null values when returning with the specified return value condition.</summary>
+	[AttributeUsage (AttributeTargets.Method | AttributeTargets.Property, Inherited = false, AllowMultiple = true)]
+	internal sealed class MemberNotNullWhenAttribute : Attribute
+	{
+		/// <summary>Initializes the attribute with the specified return value condition and a field or property member.</summary>
+		/// <param name="returnValue">
+		/// The return value condition. If the method returns this value, the associated parameter will not be null.
+		/// </param>
+		/// <param name="member">
+		/// The field or property member that is promised to be not-null.
+		/// </param>
+		public MemberNotNullWhenAttribute (bool returnValue, string member)
+		{
+			ReturnValue = returnValue;
+			Members = new[] { member };
+		}
+
+		/// <summary>Initializes the attribute with the specified return value condition and list of field and property members.</summary>
+		/// <param name="returnValue">
+		/// The return value condition. If the method returns this value, the associated parameter will not be null.
+		/// </param>
+		/// <param name="members">
+		/// The list of field and property members that are promised to be not-null.
+		/// </param>
+		public MemberNotNullWhenAttribute (bool returnValue, params string[] members)
+		{
+			ReturnValue = returnValue;
+			Members = members;
+		}
+
+		/// <summary>Gets the return value condition.</summary>
+		public bool ReturnValue { get; }
+
+		/// <summary>Gets field or property member names.</summary>
+		public string[] Members { get; }
+	}
+
+#endif
+}