Make code fix available in arguments

Author: AArnott

src/CSharpIsNullAnalyzer.CodeFixes/CSIsNull001Fixer.cs

@@ -34,7 +34,7 @@ public override async Task RegisterCodeFixesAsync(CodeFixContext context)
                 if (diagnostic.Id == CSIsNull001.Id)
                 {
                     SyntaxNode? syntaxRoot = await context.Document.GetSyntaxRootAsync(context.CancellationToken);
-                    BinaryExpressionSyntax? expr = syntaxRoot?.FindNode(diagnostic.Location.SourceSpan).FirstAncestorOrSelf<BinaryExpressionSyntax>();
+                    BinaryExpressionSyntax? expr = syntaxRoot?.FindNode(diagnostic.Location.SourceSpan, getInnermostNodeForTie: true).FirstAncestorOrSelf<BinaryExpressionSyntax>();
                     if (expr is not null)
                     {
                         context.RegisterCodeFix(

src/CSharpIsNullAnalyzer.CodeFixes/CSIsNull002Fixer.cs

@@ -46,7 +46,7 @@ public override async Task RegisterCodeFixesAsync(CodeFixContext context)
                 if (diagnostic.Id == CSIsNull002.Id)
                 {
                     SyntaxNode? syntaxRoot = await context.Document.GetSyntaxRootAsync(context.CancellationToken);
-                    BinaryExpressionSyntax? expr = syntaxRoot?.FindNode(diagnostic.Location.SourceSpan).FirstAncestorOrSelf<BinaryExpressionSyntax>();
+                    BinaryExpressionSyntax? expr = syntaxRoot?.FindNode(diagnostic.Location.SourceSpan, getInnermostNodeForTie: true).FirstAncestorOrSelf<BinaryExpressionSyntax>();
                     if (expr is not null)
                     {
                         context.RegisterCodeFix(

test/CSharpIsNullAnalyzer.Tests/CSIsNull001Tests.cs

@@ -98,4 +98,32 @@ void Method(object o)
 
         await VerifyCS.VerifyCodeFixAsync(source, fixedSource);
     }
+
+    [Fact]
+    public async Task EqualsInArgument_ProducesDiagnostic()
+    {
+        string source = @"
+class Test
+{
+    void Method(object o)
+    {
+        Other(o [|== null|]);
+    }
+
+    void Other(bool condition) { }
+}";
+
+        string fixedSource = @"
+class Test
+{
+    void Method(object o)
+    {
+        Other(o is null);
+    }
+
+    void Other(bool condition) { }
+}";
+
+        await VerifyCS.VerifyCodeFixAsync(source, fixedSource);
+    }
 }

test/CSharpIsNullAnalyzer.Tests/CSIsNull002Tests.cs

@@ -137,4 +137,44 @@ void Method(object o)
         await VerifyCS.VerifyCodeFixAsync(source, fixedSource1, CSIsNull002Fixer.IsObjectEquivalenceKey);
         await VerifyCS.VerifyCodeFixAsync(source, fixedSource2, CSIsNull002Fixer.IsNotNullEquivalenceKey);
     }
+
+    [Fact]
+    public async Task NullNotEqualsInArgument_ProducesDiagnostic()
+    {
+        string source = @"
+class Test
+{
+    void Method(object o)
+    {
+        Other([|null !=|] o);
+    }
+
+    void Other(bool condition) { }
+}";
+
+        string fixedSource1 = @"
+class Test
+{
+    void Method(object o)
+    {
+        Other(o is object);
+    }
+
+    void Other(bool condition) { }
+}";
+
+        string fixedSource2 = @"
+class Test
+{
+    void Method(object o)
+    {
+        Other(o is not null);
+    }
+
+    void Other(bool condition) { }
+}";
+
+        await VerifyCS.VerifyCodeFixAsync(source, fixedSource1, CSIsNull002Fixer.IsObjectEquivalenceKey);
+        await VerifyCS.VerifyCodeFixAsync(source, fixedSource2, CSIsNull002Fixer.IsNotNullEquivalenceKey);
+    }
 }