feat: Migrate NullConditionalAssertion to IOperation (#280)

* feat: Migrate NullConditionalAssertion to IOperation

* feat: Migrate NullConditionalAssertion to IOperation

Author: Meir017

src/FluentAssertions.Analyzers.Tests/Tips/NullConditionalAssertionTests.cs

@@ -18,14 +18,15 @@ public class NullConditionalAssertionTests
         public void NullConditionalMayNotExecuteTest(string assertion)
         {
             DiagnosticVerifier.VerifyDiagnostic(new DiagnosticVerifierArguments()
-                .WithDiagnosticAnalyzer<NullConditionalAssertionAnalyzer>()
+                .WithDiagnosticAnalyzer<FluentAssertionsOperationAnalyzer>()
                 .WithSources(Code(assertion))
                 .WithPackageReferences(PackageReference.FluentAssertions_6_12_0)
                 .WithExpectedDiagnostics(new DiagnosticResult
                 {
-                    Id = NullConditionalAssertionAnalyzer.DiagnosticId,
-                    Message = NullConditionalAssertionAnalyzer.Message,
-                    Severity = Microsoft.CodeAnalysis.DiagnosticSeverity.Warning,
+                    Id = FluentAssertionsOperationAnalyzer.DiagnosticId,
+                    Message = DiagnosticMetadata.NullConditionalMayNotExecute.Message,
+                    Severity = Microsoft.CodeAnalysis.DiagnosticSeverity.Info, // TODO: change to warning
+                    VisitorName = nameof(DiagnosticMetadata.NullConditionalMayNotExecute),
                     Locations = new DiagnosticResultLocation[]
                     {
                         new DiagnosticResultLocation("Test0.cs", 11, 13)
@@ -37,12 +38,12 @@ public void NullConditionalMayNotExecuteTest(string assertion)
         [DataTestMethod]
         [AssertionDiagnostic("(actual?.MyProperty).Should().Be(\"test\"{0});")]
         [AssertionDiagnostic("actual.MyProperty.Should().Be(actual?.MyProperty{0});")]
-        [AssertionDiagnostic("actual.MyList.Where(obj => obj?.ToString() == null).Count().Should().Be(0{0});")]
+        [AssertionDiagnostic("actual.MyList.Where(obj => obj?.ToString() == null).Should().HaveCount(6{0});")]
         [Implemented]
         public void NullConditionalWillStillExecuteTest(string assertion)
         {
             DiagnosticVerifier.VerifyDiagnostic(new DiagnosticVerifierArguments()
-                .WithDiagnosticAnalyzer<NullConditionalAssertionAnalyzer>()
+                .WithDiagnosticAnalyzer<FluentAssertionsOperationAnalyzer>()
                 .WithSources(Code(assertion))
                 .WithPackageReferences(PackageReference.FluentAssertions_6_12_0)
             );

src/FluentAssertions.Analyzers.Tests/Tips/SanityTests.cs

@@ -441,9 +441,9 @@ public class MyCollectionType { }";
                 .WithPackageReferences(PackageReference.FluentAssertions_6_12_0)
                 .WithExpectedDiagnostics(new DiagnosticResult()
                 {
-                    Id = NullConditionalAssertionAnalyzer.DiagnosticId,
-                    Message = NullConditionalAssertionAnalyzer.Message,
-                    Severity = DiagnosticSeverity.Warning,
+                    Id = FluentAssertionsOperationAnalyzer.DiagnosticId,
+                    Message = DiagnosticMetadata.NullConditionalMayNotExecute.Message,
+                    Severity = DiagnosticSeverity.Info, // TODO: change to warning
                     Locations = new[] { new DiagnosticResultLocation("Test0.cs", 13, 9) }
                 })
             );

src/FluentAssertions.Analyzers/Constants.cs

@@ -18,7 +18,6 @@ public static class CodeSmell
     {
         public const string Category = "FluentAssertionCodeSmell";
 
-        public const string NullConditionalAssertion = $"{DiagnosticProperties.IdPrefix}0800";
         public const string AsyncVoid = $"{DiagnosticProperties.IdPrefix}0801";
         public const string ShouldEquals = $"{DiagnosticProperties.IdPrefix}0802";
     }

src/FluentAssertions.Analyzers/Tips/DiagnosticMetadata.cs

@@ -108,6 +108,7 @@ private DiagnosticMetadata(string message, string helpLink, [CallerMemberName] s
     public static DiagnosticMetadata CollectionShouldEqual_CollectionShouldEquals = new("Use .Should().Equal()", string.Empty);
     public static DiagnosticMetadata ShouldEquals = new("Use .Should().Be() or .Should().BeEquivalentTo or .Should().Equal() or other equivalency assertion", string.Empty);
     public static DiagnosticMetadata ShouldBe_ShouldEquals = new("Use .Should().Be()", string.Empty);
+    public static DiagnosticMetadata NullConditionalMayNotExecute = new("Use .Should() instead of ?.Should()", string.Empty);
 
     private static string GetHelpLink(string id) => $"https://fluentassertions.com/tips/#{id}";
 }

src/FluentAssertions.Analyzers/Tips/FluentAssertionsCodeFixProvider.cs

@@ -25,7 +25,7 @@ protected override CreateChangedDocument TryComputeFix(IInvocationOperation asse
             return null;
         }
 
-        if (visitorName is nameof(DiagnosticMetadata.ShouldEquals))
+        if (visitorName is nameof(DiagnosticMetadata.ShouldEquals) or nameof(DiagnosticMetadata.NullConditionalMayNotExecute))
         {
             return null;
         }

src/FluentAssertions.Analyzers/Tips/FluentAssertionsOperationAnalyzer.Utils.cs

@@ -5,6 +5,7 @@
 using System.Linq;
 using System.Threading.Tasks;
 using Microsoft.CodeAnalysis;
+using Microsoft.CodeAnalysis.Editing;
 using Microsoft.CodeAnalysis.Operations;
 
 namespace FluentAssertions.Analyzers;
@@ -36,6 +37,22 @@ private static bool TryGetExceptionPropertyAssertion(IInvocationOperation assert
         return false;
     }
 
+    private static bool HasConditionalAccessAncestor(IInvocationOperation invocation)
+    {
+        var current = invocation.Parent;
+        while (current is not null)
+        {
+            if (current.Kind is OperationKind.ConditionalAccess)
+            {
+                return true;
+            }
+
+            current = current.Parent;
+        }
+
+        return false;
+    }
+
     private class FluentAssertionsMetadata
     {
         public FluentAssertionsMetadata(Compilation compilation)

src/FluentAssertions.Analyzers/Tips/FluentAssertionsOperationAnalyzer.cs

@@ -49,10 +49,12 @@ private static void AnalyzeInvocation(OperationAnalysisContext context, FluentAs
         {
             return;
         }
-        
-        if (assertion.Parent.Kind is OperationKind.ConditionalAccess)
+
+        if (HasConditionalAccessAncestor(invocation))
         {
-            return; // Handled by NullConditionalAssertionAnalyzer
+            var expressionStatement = invocation.GetFirstAncestor<IExpressionStatementOperation>();
+            context.ReportDiagnostic(CreateDiagnostic(expressionStatement, DiagnosticMetadata.NullConditionalMayNotExecute));
+            return;
         }
 
         var subject = invocation.Arguments[0].Value;