Port single-file analyzer (#1665)

* Add single-file analyzer

* Add tests

* Use str constant

* Update Resources

* Update tests

* PR feedback

* Remove mysterious filename from comments

* Add helper method for single-file diagnostic verification

* Refactor MSBuild properties

* Add test with PublishSingleFile not set

5 files changed, 168 insertions, 14 deletions

diff --git a/test/ILLink.RoslynAnalyzer.Tests/AvoidAssemblyLocationInSingleFileTests.cs b/test/ILLink.RoslynAnalyzer.Tests/AvoidAssemblyLocationInSingleFileTests.cs
new file mode 100644
index 000000000..0ea712f97
--- /dev/null
+++ b/test/ILLink.RoslynAnalyzer.Tests/AvoidAssemblyLocationInSingleFileTests.cs
@@ -0,0 +1,144 @@
+// 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.
+
+using System.Threading.Tasks;
+using Microsoft.CodeAnalysis.Testing;
+using Xunit;
+using VerifyCS = ILLink.RoslynAnalyzer.Tests.CSharpAnalyzerVerifier<
+	ILLink.RoslynAnalyzer.AvoidAssemblyLocationInSingleFile>;
+
+namespace ILLink.RoslynAnalyzer.Tests
+{
+	public class AvoidAssemblyLocationInSingleFileTests
+	{
+		static Task VerifySingleFileAnalyzer (string source, params DiagnosticResult[] expected)
+		{
+			return VerifyCS.VerifyAnalyzerAsync (source,
+				TestCaseUtils.UseMSBuildProperties (MSBuildPropertyOptionNames.PublishSingleFile),
+				expected);
+		}
+
+		[Fact]
+		public Task GetExecutingAssemblyLocation ()
+		{
+			const string src = @"
+using System.Reflection;
+class C
+{
+    public string M() => Assembly.GetExecutingAssembly().Location;
+}";
+
+			return VerifySingleFileAnalyzer (src,
+				// (5,26): warning IL3000: 'System.Reflection.Assembly.Location' always returns an empty string for assemblies embedded in a single-file app. If the path to the app directory is needed, consider calling 'System.AppContext.BaseDirectory'.
+				VerifyCS.Diagnostic (AvoidAssemblyLocationInSingleFile.IL3000).WithSpan (5, 26, 5, 66).WithArguments ("System.Reflection.Assembly.Location"));
+		}
+
+		[Fact]
+		public Task AssemblyProperties ()
+		{
+			var src = @"
+using System.Reflection;
+class C
+{
+    public void M()
+    {
+        var a = Assembly.GetExecutingAssembly();
+        _ = a.Location;
+        // below methods are marked as obsolete in 5.0
+        // _ = a.CodeBase;
+        // _ = a.EscapedCodeBase;
+    }
+}";
+			return VerifySingleFileAnalyzer (src,
+				// (8,13): warning IL3000: 'System.Reflection.Assembly.Location' always returns an empty string for assemblies embedded in a single-file app. If the path to the app directory is needed, consider calling 'System.AppContext.BaseDirectory'.
+				VerifyCS.Diagnostic (AvoidAssemblyLocationInSingleFile.IL3000).WithSpan (8, 13, 8, 23).WithArguments ("System.Reflection.Assembly.Location")
+			);
+		}
+
+		[Fact]
+		public Task AssemblyMethods ()
+		{
+			var src = @"
+using System.Reflection;
+class C
+{
+    public void M()
+    {
+        var a = Assembly.GetExecutingAssembly();
+        _ = a.GetFile(""/some/file/path"");
+        _ = a.GetFiles();
+    }
+}";
+			return VerifySingleFileAnalyzer (src,
+				// (8,13): warning IL3001: Assemblies embedded in a single-file app cannot have additional files in the manifest.
+				VerifyCS.Diagnostic (AvoidAssemblyLocationInSingleFile.IL3001).WithSpan (8, 13, 8, 41).WithArguments ("System.Reflection.Assembly.GetFile(string)"),
+				// (9,13): warning IL3001: Assemblies embedded in a single-file app cannot have additional files in the manifest.
+				VerifyCS.Diagnostic (AvoidAssemblyLocationInSingleFile.IL3001).WithSpan (9, 13, 9, 25).WithArguments ("System.Reflection.Assembly.GetFiles()")
+				);
+		}
+
+		[Fact]
+		public Task AssemblyNameAttributes ()
+		{
+			var src = @"
+using System.Reflection;
+class C
+{
+    public void M()
+    {
+        var a = Assembly.GetExecutingAssembly().GetName();
+        _ = a.CodeBase;
+        _ = a.EscapedCodeBase;
+    }
+}";
+			return VerifySingleFileAnalyzer (src,
+				// (8,13): warning IL3000: 'System.Reflection.AssemblyName.CodeBase' always returns an empty string for assemblies embedded in a single-file app. If the path to the app directory is needed, consider calling 'System.AppContext.BaseDirectory'.
+				VerifyCS.Diagnostic (AvoidAssemblyLocationInSingleFile.IL3000).WithSpan (8, 13, 8, 23).WithArguments ("System.Reflection.AssemblyName.CodeBase"),
+				// (9,13): warning IL3000: 'System.Reflection.AssemblyName.EscapedCodeBase' always returns an empty string for assemblies embedded in a single-file app. If the path to the app directory is needed, consider calling 'System.AppContext.BaseDirectory'.
+				VerifyCS.Diagnostic (AvoidAssemblyLocationInSingleFile.IL3000).WithSpan (9, 13, 9, 30).WithArguments ("System.Reflection.AssemblyName.EscapedCodeBase")
+				);
+		}
+
+		[Fact]
+		public Task FalsePositive ()
+		{
+			// This is an OK use of Location and GetFile since these assemblies were loaded from
+			// a file, but the analyzer is conservative
+			var src = @"
+using System.Reflection;
+class C
+{
+    public void M()
+    {
+        var a = Assembly.LoadFrom(""/some/path/not/in/bundle"");
+        _ = a.Location;
+        _ = a.GetFiles();
+    }
+}";
+			return VerifySingleFileAnalyzer (src,
+				// (8,13): warning IL3000: 'System.Reflection.Assembly.Location' always returns an empty string for assemblies embedded in a single-file app. If the path to the app directory is needed, consider calling 'System.AppContext.BaseDirectory'.
+				VerifyCS.Diagnostic (AvoidAssemblyLocationInSingleFile.IL3000).WithSpan (8, 13, 8, 23).WithArguments ("System.Reflection.Assembly.Location"),
+				// (9,13): warning IL3001: Assemblies embedded in a single-file app cannot have additional files in the manifest.
+				VerifyCS.Diagnostic (AvoidAssemblyLocationInSingleFile.IL3001).WithSpan (9, 13, 9, 25).WithArguments ("System.Reflection.Assembly.GetFiles()")
+				);
+		}
+
+		[Fact]
+		public Task PublishSingleFileIsNotSet ()
+		{
+			var src = @"
+using System.Reflection;
+class C
+{
+    public void M()
+    {
+        var a = Assembly.GetExecutingAssembly().Location;
+    }
+}";
+			// If 'PublishSingleFile' is not set to true, no diagnostics should be produced by the analyzer. This will
+			// effectively verify that the number of produced diagnostics matches the number of expected ones (zero).
+			return VerifyCS.VerifyAnalyzerAsync (src);
+		}
+	}
+}
diff --git a/test/ILLink.RoslynAnalyzer.Tests/LinkerTestCases.cs b/test/ILLink.RoslynAnalyzer.Tests/LinkerTestCases.cs
index e63d2c02f..f205fb25e 100644
--- a/test/ILLink.RoslynAnalyzer.Tests/LinkerTestCases.cs
+++ b/test/ILLink.RoslynAnalyzer.Tests/LinkerTestCases.cs
@@ -3,8 +3,6 @@
 // See the LICENSE file in the project root for more information.
 
 using System.Collections.Generic;
-using System.Collections.Immutable;
-using Microsoft.CodeAnalysis;
 using Microsoft.CodeAnalysis.CSharp.Syntax;
 using Xunit;
 
@@ -24,7 +22,7 @@ namespace ILLink.RoslynAnalyzer.Tests
 			case "MethodWithDuplicateRequiresAttribute":
 				return;
 			}
-			RunTest (m, attrs);
+			RunTest (m, attrs, UseMSBuildProperties (MSBuildPropertyOptionNames.PublishTrimmed));
 		}
 	}
 }
diff --git a/test/ILLink.RoslynAnalyzer.Tests/AnalyzerTests.cs b/test/ILLink.RoslynAnalyzer.Tests/RequiresUnreferencedCodeAnalyzerTests.cs
index fc1ee182d..81899e890 100644
--- a/test/ILLink.RoslynAnalyzer.Tests/AnalyzerTests.cs
+++ b/test/ILLink.RoslynAnalyzer.Tests/RequiresUnreferencedCodeAnalyzerTests.cs
@@ -3,14 +3,22 @@
 // See the LICENSE file in the project root for more information.
 
 using System.Threading.Tasks;
+using Microsoft.CodeAnalysis.Testing;
 using Xunit;
 using VerifyCS = ILLink.RoslynAnalyzer.Tests.CSharpAnalyzerVerifier<
 	ILLink.RoslynAnalyzer.RequiresUnreferencedCodeAnalyzer>;
 
 namespace ILLink.RoslynAnalyzer.Tests
 {
-	public class AnalyzerTests
+	public class RequiresUnreferencedCodeAnalyzerTests
 	{
+		static Task VerifyRequiresUnreferencedCodeAnalyzer (string source, params DiagnosticResult[] expected)
+		{
+			return VerifyCS.VerifyAnalyzerAsync (source,
+				TestCaseUtils.UseMSBuildProperties (MSBuildPropertyOptionNames.PublishTrimmed),
+				expected);
+		}
+
 		[Fact]
 		public Task SimpleDiagnostic ()
 		{
@@ -23,10 +31,9 @@ class C
     int M1() => 0;
     int M2() => M1();
 }";
-			return VerifyCS.VerifyAnalyzerAsync (TestRequiresWithMessageOnlyOnMethod,
+			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", "")
-				);
+				VerifyCS.Diagnostic ().WithSpan (8, 17, 8, 21).WithArguments ("C.M1()", "message", ""));
 		}
 
 		[Fact]
@@ -46,7 +53,7 @@ class C
 	{
 	}
 }";
-			return VerifyCS.VerifyAnalyzerAsync (MessageAndUrlOnMethod,
+			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")
 				);
@@ -70,7 +77,7 @@ class C
 		get { return 42; }
 	}
 }";
-			return VerifyCS.VerifyAnalyzerAsync (PropertyRequires,
+			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--", "")
 				);
@@ -94,7 +101,7 @@ class C
 		set { }
 	}
 }";
-			return VerifyCS.VerifyAnalyzerAsync (PropertyRequires,
+			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 003823c02..c62c2d762 100644
--- a/test/ILLink.RoslynAnalyzer.Tests/TestCaseUtils.cs
+++ b/test/ILLink.RoslynAnalyzer.Tests/TestCaseUtils.cs
@@ -53,9 +53,9 @@ namespace ILLink.RoslynAnalyzer.Tests
 			}
 		}
 
-		internal static void RunTest (MethodDeclarationSyntax m, List<AttributeSyntax> attrs)
+		internal static void RunTest (MethodDeclarationSyntax m, List<AttributeSyntax> attrs, params (string, string)[] MSBuildProperties)
 		{
-			var comp = CSharpAnalyzerVerifier<RequiresUnreferencedCodeAnalyzer>.CreateCompilation (m.SyntaxTree).Result;
+			var comp = CSharpAnalyzerVerifier<RequiresUnreferencedCodeAnalyzer>.CreateCompilation (m.SyntaxTree, MSBuildProperties).Result;
 			var diags = comp.GetAnalyzerDiagnosticsAsync ().Result;
 
 			var filtered = diags.Where (d => d.Location.SourceSpan.IntersectsWith (m.Span))
@@ -181,6 +181,11 @@ In diagnostics:
 			}
 		}
 
+		internal static (string, string)[] UseMSBuildProperties (params string[] MSBuildProperties)
+		{
+			return MSBuildProperties.Select (msbp => ($"build_property.{msbp}", "true")).ToArray ();
+		}
+
 		internal static void GetDirectoryPaths (out string rootSourceDirectory, out string testAssemblyPath, [CallerFilePath] string thisFile = null)
 		{
 
diff --git a/test/ILLink.RoslynAnalyzer.Tests/Verifiers/CSharpAnalyzerVerifier`1.cs b/test/ILLink.RoslynAnalyzer.Tests/Verifiers/CSharpAnalyzerVerifier`1.cs
index 91b28b1aa..4d96f37d8 100644
--- a/test/ILLink.RoslynAnalyzer.Tests/Verifiers/CSharpAnalyzerVerifier`1.cs
+++ b/test/ILLink.RoslynAnalyzer.Tests/Verifiers/CSharpAnalyzerVerifier`1.cs
@@ -71,9 +71,9 @@ namespace ILLink.RoslynAnalyzer.Tests
 		}
 
 		/// <inheritdoc cref="AnalyzerVerifier{TAnalyzer, TTest, TVerifier}.VerifyAnalyzerAsync(string, DiagnosticResult[])"/>
-		public static async Task VerifyAnalyzerAsync (string src, params DiagnosticResult[] expected)
+		public static async Task VerifyAnalyzerAsync (string src, (string, string)[]? analyzerOptions = null, params DiagnosticResult[] expected)
 		{
-			var diags = await (await CreateCompilation (src)).GetAllDiagnosticsAsync ();
+			var diags = await (await CreateCompilation (src, analyzerOptions)).GetAllDiagnosticsAsync ();
 
 			var analyzers = ImmutableArray.Create<DiagnosticAnalyzer> (new TAnalyzer ());
 			VerifyDiagnosticResults (diags, analyzers, expected, DefaultVerifier);