Add analyzer for RequiresAssemblyFilesAttribute (#1722)

3 files changed, 152 insertions, 5 deletions

diff --git a/test/ILLink.RoslynAnalyzer.Tests/RequiresAssemblyFilesAnalyzerTests.cs b/test/ILLink.RoslynAnalyzer.Tests/RequiresAssemblyFilesAnalyzerTests.cs
new file mode 100644
index 000000000..466f81db8
--- /dev/null
+++ b/test/ILLink.RoslynAnalyzer.Tests/RequiresAssemblyFilesAnalyzerTests.cs
@@ -0,0 +1,152 @@
+using System;
+using System.Threading.Tasks;
+using Microsoft.CodeAnalysis.Testing;
+using Xunit;
+using VerifyCS = ILLink.RoslynAnalyzer.Tests.CSharpAnalyzerVerifier<
+	ILLink.RoslynAnalyzer.RequiresAssemblyFilesAnalyzer>;
+
+namespace ILLink.RoslynAnalyzer.Tests
+{
+	public class RequiresAssemblyFilesAnalyzerTests
+	{
+		static Task VerifyRequiresAssemblyFilesAnalyzer (string source, params DiagnosticResult[] expected)
+		{
+			// TODO: Remove this once we have the new attribute in the runtime.
+			source = @"namespace System.Diagnostics.CodeAnalysis
+{
+#nullable enable
+    [AttributeUsage(AttributeTargets.Constructor |
+                    AttributeTargets.Event |
+                    AttributeTargets.Method |
+                    AttributeTargets.Property,
+                    Inherited = false,
+                    AllowMultiple = false)]
+    public sealed class RequiresAssemblyFilesAttribute : Attribute
+    {
+			public RequiresAssemblyFilesAttribute() { }
+			public string? Message { get; set; }
+			public string? Url { get; set; }
+	}
+}" + Environment.NewLine + source;
+			return VerifyCS.VerifyAnalyzerAsync (source,
+				TestCaseUtils.UseMSBuildProperties (MSBuildPropertyOptionNames.PublishSingleFile),
+				expected);
+		}
+
+		[Fact]
+		public Task SimpleDiagnosticOnEvent ()
+		{
+			var TestRequiresAssemblyFieldsOnEvent = @"
+class C
+{
+	[System.Diagnostics.CodeAnalysis.RequiresAssemblyFiles]
+	event System.EventHandler? E;
+
+	void M()
+	{
+		var handler = E;
+	}
+}";
+			return VerifyRequiresAssemblyFilesAnalyzer (TestRequiresAssemblyFieldsOnEvent,
+				VerifyCS.Diagnostic ().WithSpan (25, 17, 25, 18).WithArguments ("C.E"));
+		}
+
+		[Fact]
+		public Task SimpleDiagnosticOnMethod ()
+		{
+			var TestRequiresAssemblyFilesOnMethod = @"
+class C
+{
+	[System.Diagnostics.CodeAnalysis.RequiresAssemblyFiles]
+	void M1()
+	{
+	}
+
+	void M2()
+	{
+		M1();
+	}
+}";
+			return VerifyRequiresAssemblyFilesAnalyzer (TestRequiresAssemblyFilesOnMethod,
+				VerifyCS.Diagnostic ().WithSpan (27, 3, 27, 7).WithArguments ("C.M2()"));
+		}
+
+		[Fact]
+		public Task SimpleDiagnosticOnProperty ()
+		{
+			var TestRequiresAssemblyFilesOnProperty = @"
+class C
+{
+	[System.Diagnostics.CodeAnalysis.RequiresAssemblyFiles]
+	bool P { get; set; }
+
+	void M()
+	{
+		P = false;
+		bool b = P;
+	}
+}";
+			return VerifyRequiresAssemblyFilesAnalyzer (TestRequiresAssemblyFilesOnProperty,
+				VerifyCS.Diagnostic ().WithSpan (25, 3, 25, 4).WithArguments ("C.P"),
+				VerifyCS.Diagnostic ().WithSpan (26, 12, 26, 13).WithArguments ("C.P"));
+		}
+
+		[Fact]
+		public Task RequiresAssemblyFilesWithMessageAndUrl ()
+		{
+			var TestRequiresAssemblyFilesWithMessageAndUrl = @"
+class C
+{
+	[System.Diagnostics.CodeAnalysis.RequiresAssemblyFiles (Message = ""Message from attribute"", Url = ""https://helpurl"")]
+	void M1()
+	{
+	}
+
+	void M2()
+	{
+		M1();
+	}
+}";
+			return VerifyRequiresAssemblyFilesAnalyzer (TestRequiresAssemblyFilesWithMessageAndUrl,
+				VerifyCS.Diagnostic ().WithSpan (27, 3, 27, 7).WithArguments ("C.M2()", "Message from attribute", "https://helpurl"));
+		}
+
+		[Fact]
+		public Task NoDiagnosticIfMethodNotCalled ()
+		{
+			var TestNoDiagnosticIfMethodNotCalled = @"
+class C
+{
+	[System.Diagnostics.CodeAnalysis.RequiresAssemblyFiles]
+	void M() { }
+}";
+			return VerifyRequiresAssemblyFilesAnalyzer (TestNoDiagnosticIfMethodNotCalled);
+		}
+
+		[Fact]
+		public Task NoDiagnosticIsProducedIfCallerIsAnnotated ()
+		{
+			var TestNoDiagnosticIsProducedIfCallerIsAnnotated = @"
+class C
+{
+	void M1()
+	{
+		M2();
+	}
+
+	[System.Diagnostics.CodeAnalysis.RequiresAssemblyFiles (Message = ""Warn from M2"")]
+	void M2()
+	{
+		M3();
+	}
+
+	[System.Diagnostics.CodeAnalysis.RequiresAssemblyFiles (Message = ""Warn from M3"")]
+	void M3()
+	{
+	}
+}";
+			return VerifyRequiresAssemblyFilesAnalyzer (TestNoDiagnosticIsProducedIfCallerIsAnnotated,
+				VerifyCS.Diagnostic ().WithSpan (22, 3, 22, 7).WithArguments ("C.M2()", "Warn from M2"));
+		}
+	}
+}
diff --git a/test/ILLink.RoslynAnalyzer.Tests/RequiresUnreferencedCodeAnalyzerTests.cs b/test/ILLink.RoslynAnalyzer.Tests/RequiresUnreferencedCodeAnalyzerTests.cs
index 81899e890..25050d507 100644
--- a/test/ILLink.RoslynAnalyzer.Tests/RequiresUnreferencedCodeAnalyzerTests.cs
+++ b/test/ILLink.RoslynAnalyzer.Tests/RequiresUnreferencedCodeAnalyzerTests.cs
@@ -32,7 +32,6 @@ class C
     int M2() => M1();
 }";
 			return VerifyRequiresUnreferencedCodeAnalyzer (TestRequiresWithMessageOnlyOnMethod,
-				// (8,17): warning IL2026: Calling 'System.Int32 C::M1()' which has `RequiresUnreferencedCodeAttribute` can break functionality when trimming application code. message.
 				VerifyCS.Diagnostic ().WithSpan (8, 17, 8, 21).WithArguments ("C.M1()", "message", ""));
 		}
 
@@ -54,7 +53,6 @@ class C
 	}
 }";
 			return VerifyRequiresUnreferencedCodeAnalyzer (MessageAndUrlOnMethod,
-				// (8,3): warning IL2026: Calling 'C.RequiresWithMessageAndUrl()' which has `RequiresUnreferencedCodeAttribute` can break functionality when trimming application code. Message for --RequiresWithMessageAndUrl--.
 				VerifyCS.Diagnostic ().WithSpan (8, 3, 8, 31).WithArguments ("C.RequiresWithMessageAndUrl()", "Message for --RequiresWithMessageAndUrl--", "https://helpurl")
 				);
 		}
@@ -78,7 +76,6 @@ class C
 	}
 }";
 			return VerifyRequiresUnreferencedCodeAnalyzer (PropertyRequires,
-				// (8,7): warning IL2026: Calling 'C.PropertyRequires.get' which has `RequiresUnreferencedCodeAttribute` can break functionality when trimming application code. Message for --getter PropertyRequires--.
 				VerifyCS.Diagnostic ().WithSpan (8, 7, 8, 23).WithArguments ("C.PropertyRequires.get", "Message for --getter PropertyRequires--", "")
 				);
 		}
@@ -102,7 +99,6 @@ class C
 	}
 }";
 			return VerifyRequiresUnreferencedCodeAnalyzer (PropertyRequires,
-				// (8,3): warning IL2026: Calling 'C.PropertyRequires.set' which has `RequiresUnreferencedCodeAttribute` can break functionality when trimming application code. Message for --setter PropertyRequires--. 
 				VerifyCS.Diagnostic ().WithSpan (8, 3, 8, 19).WithArguments ("C.PropertyRequires.set", "Message for --setter PropertyRequires--", "")
 				);
 		}
diff --git a/test/ILLink.RoslynAnalyzer.Tests/TestCaseUtils.cs b/test/ILLink.RoslynAnalyzer.Tests/TestCaseUtils.cs
index d334559bf..749f9097f 100644
--- a/test/ILLink.RoslynAnalyzer.Tests/TestCaseUtils.cs
+++ b/test/ILLink.RoslynAnalyzer.Tests/TestCaseUtils.cs
@@ -11,7 +11,6 @@ using System.Runtime.CompilerServices;
 using Microsoft.CodeAnalysis;
 using Microsoft.CodeAnalysis.CSharp;
 using Microsoft.CodeAnalysis.CSharp.Syntax;
-using Mono.Linker.Tests.Cases.Expectations.Assertions;
 using Xunit;
 
 namespace ILLink.RoslynAnalyzer.Tests