feat: Protect compiler directives during mutation

docs/technical-reference/Mutation Orchestration Design.md

@@ -262,8 +262,7 @@ This class is used for several constructs:
 - `AttributeListSyntax`: Attributes must be defined at compile time.
 - `ParameterListSyntax`: Parameters and default values must be known at compile time.
 - `EnumMemberSyntax`: Enumeration value must be known at compile time
--  `RecursivePatternSyntax`: Pattern syntax must be known at compile time.
--  `UsingDirectiveSyntax`: using directives are fixed and critical for compilation
+- `UsingDirectiveSyntax`: using directives are fixed and critical for compilation
 - `FieldDeclarationSyntax`  (only const fields): cannot modify const fields at run time.
 - `LocalDeclarationStatementSyntax` (only const): cannot modify constants at run time.
 

integrationtest/TargetProjects/NetCore/EmptyTestProject/Main.cs

@@ -0,0 +1,2 @@
+
+Console.WriteLine("this is a global statement");

integrationtest/Validation/ValidationProject/ValidateStrykerResults.cs

@@ -83,7 +83,7 @@ public async Task CSharp_NetCore_SingleTestProject()
 
         var report = await strykerRunOutput.DeserializeJsonReportAsync();
 
-        CheckReportMutants(report, total: 601, ignored: 247, survived: 4, killed: 9, timeout: 2, nocoverage: 308);
+        CheckReportMutants(report, total: 606, ignored: 252, survived: 4, killed: 9, timeout: 2, nocoverage: 308);
         CheckReportTestCounts(report, total: 11);
     }
 
@@ -101,8 +101,8 @@ public async Task CSharp_NetCore_WithTwoTestProjects()
         using var strykerRunOutput = File.OpenRead(latestReport.FullName);
 
         var report = await strykerRunOutput.DeserializeJsonReportAsync();
-
-        CheckReportMutants(report, total: 601, ignored: 105, survived: 5, killed: 11, timeout: 2, nocoverage: 447);
+         
+        CheckReportMutants(report, total: 606, ignored: 105, survived: 5, killed: 11, timeout: 2, nocoverage: 452);
         CheckReportTestCounts(report, total: 21);
     }
 
@@ -121,7 +121,7 @@ public async Task CSharp_NetCore_SolutionRun()
 
         var report = await strykerRunOutput.DeserializeJsonReportAsync();
 
-        CheckReportMutants(report, total: 601, ignored: 247, survived: 4, killed: 9, timeout: 2, nocoverage: 308);
+        CheckReportMutants(report, total: 606, ignored: 252, survived: 4, killed: 9, timeout: 2, nocoverage: 308);
         CheckReportTestCounts(report, total: 23);
     }
 

src/Stryker.Core/Stryker.Core.UnitTest/AssertExtensions.cs

@@ -1,7 +1,9 @@
 using Microsoft.CodeAnalysis;
 using Microsoft.CodeAnalysis.CSharp;
+using Microsoft.CodeAnalysis.CSharp.Syntax;
 using Shouldly;
 using System;
+using System.Collections.Generic;
 using System.IO.Abstractions.TestingHelpers;
 using System.Linq;
 
@@ -32,21 +34,36 @@ public static void ShouldBeSemantically(this SyntaxTree actual, SyntaxTree expec
 
         if (!isSame)
         {
-            // find the different
-            var actualLines = actual.ToString().Split(Environment.NewLine);
-            var expectedLines = expected.ToString().Split(Environment.NewLine);
-            for (var i = 0; i < actualLines.Length; i++)
+            var diff = ScanDiff(actual.GetRoot(), expected.GetRoot());
+
+            Console.WriteLine(string.Join(Environment.NewLine, diff));
+
+        }
+    }
+
+    private static List<string> ScanDiff(SyntaxNode actual, SyntaxNode expected)
+    {
+        var actualChildren = actual.ChildNodes().ToList();
+        var expectedChildren = expected.ChildNodes().ToList();
+        var failedStatements = new List<string>();
+        for (var i = 0; i < actualChildren.Count; i++)
+        {
+            if (expectedChildren.Count <= i)
+            {
+                failedStatements.Add($"Extra statements: {actualChildren[i]}");
+                continue;
+            }
+            if ((actualChildren[i] is not StatementSyntax) || (actualChildren[i] is BlockSyntax or IfStatementSyntax or ForStatementSyntax or WhileStatementSyntax ))
+            {
+                failedStatements.AddRange(ScanDiff(actualChildren[i], expectedChildren[i]));
+                continue;
+            }
+            if (!actualChildren[i].IsEquivalentTo(expectedChildren[i]))
             {
-                if (expectedLines.Length <= i)
-                {
-                    isSame.ShouldBeTrue($"AST's are not equivalent. Line[{i + 1}]{Environment.NewLine}actual:{actualLines[i]}{Environment.NewLine}expect: nothing{Environment.NewLine}Actual(full):{Environment.NewLine}{actual}{Environment.NewLine}, expected:{Environment.NewLine}{expected}");
-                }
-                if (actualLines[i] != expectedLines[i])
-                {
-                    isSame.ShouldBeTrue($"AST's are not equivalent. Line[{i + 1}]{Environment.NewLine}actual:{actualLines[i]}{Environment.NewLine}expect:{expectedLines[i]}{Environment.NewLine}Actual(full):{Environment.NewLine}{actual}{Environment.NewLine}, expected:{Environment.NewLine}{expected}");
-                }
+                failedStatements.Add($"Not equivalent. Actual:{Environment.NewLine}{actualChildren[i]}{Environment.NewLine}Expected:{Environment.NewLine}{expectedChildren[i]}");
             }
         }
+        return failedStatements;
     }
 
     public static void ShouldBeWithNewlineReplace(this string actual, string expected)

src/Stryker.Core/Stryker.Core.UnitTest/Initialisation/BuildAnalyzerTestsBase.cs

@@ -18,7 +18,7 @@ public class BuildAnalyzerTestsBase : TestBase
     protected internal const string DefaultFramework = "net6.0";
     protected readonly MockFileSystem FileSystem = new();
     protected string ProjectPath;
-    private readonly Dictionary<string, Dictionary<string, IAnalyzerResult>> _projectCache = new();
+    private readonly Dictionary<string, Dictionary<string, IAnalyzerResult>> _projectCache = [];
     protected readonly Mock<IBuildalyzerProvider> BuildalyzerProviderMock = new(MockBehavior.Strict);
 
     public BuildAnalyzerTestsBase()
@@ -41,7 +41,7 @@ protected Mock<IProjectAnalyzer> SourceProjectAnalyzerMock(string csprojPathName
         IEnumerable<string> projectReferences = null, string framework = DefaultFramework, Func<bool> success = null)
     {
         var properties = GetSourceProjectDefaultProperties();
-        projectReferences ??= new List<string>();
+        projectReferences ??= [];
 
         return BuildProjectAnalyzerMock(csprojPathName, sourceFiles, properties, projectReferences, [framework], success);
     }
@@ -58,7 +58,7 @@ protected Mock<IProjectAnalyzer> SourceProjectAnalyzerMock(string csprojPathName
         IEnumerable<string> projectReferences , IEnumerable<string> frameworks, Func<bool> success = null)
     {
         var properties = GetSourceProjectDefaultProperties();
-        projectReferences??= new List<string>();
+        projectReferences??= [];
 
         return BuildProjectAnalyzerMock(csprojPathName, sourceFiles, properties, projectReferences, frameworks, success);
     }
@@ -81,7 +81,7 @@ public static Dictionary<string, string> GetSourceProjectDefaultProperties()
     /// <remarks>the test project references the production code project and contains no source file</remarks>
     protected Mock<IProjectAnalyzer> TestProjectAnalyzerMock(string testCsprojPathName, string csProj, IEnumerable<string> frameworks = null, bool success = true)
     {
-        frameworks??=new []{DefaultFramework};
+        frameworks??=[DefaultFramework];
         var properties = new Dictionary<string, string>{ { "IsTestProject", "True" }, { "Language", "C#" } };
         var projectReferences =  string.IsNullOrEmpty(csProj) ? [] : GetProjectResult(csProj, frameworks.First()).ProjectReferences.Append(csProj).ToList();
         return BuildProjectAnalyzerMock(testCsprojPathName, [], properties, projectReferences, frameworks, () => success);
@@ -110,7 +110,7 @@ private IAnalyzerResult GetProjectResult(string projectFile, string expectedFram
     /// <returns>a tuple with the framework kind first and the version next</returns>
     protected static (FrameworkKind kind, decimal version) ParseFramework(string framework)
     {
-        FrameworkKind kind;
+
         decimal version;
 
         if (framework.StartsWith("netcoreapp"))
@@ -153,7 +153,7 @@ protected enum FrameworkKind
     /// <returns><paramref name="framework"/> if the framework is among the target, the best match if available, null otherwise.</returns>
     protected static string PickCompatibleFramework(string framework, IEnumerable<string> frameworks)
     {
-        var parsed = ParseFramework(framework);
+        var (kind, version) = ParseFramework(framework);
 
         string bestCandidate = null;
         var bestVersion = 1.0m;
@@ -164,12 +164,12 @@ protected static string PickCompatibleFramework(string framework, IEnumerable<st
                 return framework;
             }
             var parsedCandidate = ParseFramework(candidate);
-            if (parsedCandidate.kind != parsed.kind)
+            if (parsedCandidate.kind != kind)
             {
                 continue;
             }
 
-            if (parsedCandidate.version > parsed.version || parsedCandidate.version <= bestVersion)
+            if (parsedCandidate.version > version || parsedCandidate.version <= bestVersion)
             {
                 continue;
             }
@@ -264,7 +264,7 @@ internal Mock<IProjectAnalyzer> BuildProjectAnalyzerMock(string csprojPathName,
         return projectAnalyzerMock;
     }
 
-    private IAnalyzerResults BuildAnalyzerResultsMock(IDictionary<string, IAnalyzerResult> projectAnalyzerResults)
+    private static IAnalyzerResults BuildAnalyzerResultsMock(IDictionary<string, IAnalyzerResult> projectAnalyzerResults)
     {
         var analyzerResults = projectAnalyzerResults.Values.ToList();
         var sourceProjectAnalyzerResultsMock = new Mock<IAnalyzerResults>(MockBehavior.Strict);