New rule S2166: Classes named like "Exception" should extend "Exception" or a subclass

analyzers/rspec/cs/S2166_c#.html

@@ -0,0 +1,40 @@
+<p>Clear, communicative naming is important in code. It helps maintainers and API users understand the intentions for and uses of a unit of code.
+Using "exception" in the name of a class that does not extend <code>Exception</code> or one of its subclasses is a clear violation of the expectation
+that a class' name will indicate what it is and/or does.</p>
+<h2>Noncompliant Code Example</h2>
+<pre>
+public class FruitException // Noncompliant - this has nothing to do with Exception
+{
+  private Fruit expected;
+  private string unusualCharacteristics;
+  private bool appropriateForCommercialExploitation;
+  // ...
+}
+
+public class CarException // Noncompliant - does not derive from any Exception-based class
+{
+  public CarException(string message, Exception inner)
+  {
+     // ...
+  }
+}
+</pre>
+<h2>Compliant Solution</h2>
+<pre>
+public class FruitSport // Compliant - class name does not end with 'Exception'
+{
+  private Fruit expected;
+  private string unusualCharacteristics;
+  private bool appropriateForCommercialExploitation;
+  // ...
+}
+
+public class CarException: Exception // Compliant - correctly extends System.Exception
+{
+  public CarException(string message, Exception inner): base(message, inner)
+  {
+     // ...
+  }
+}
+</pre>
+

analyzers/rspec/cs/S2166_c#.json

@@ -0,0 +1,19 @@
+{
+  "title": "Classes named like \"Exception\" should extend \"Exception\" or a subclass",
+  "type": "CODE_SMELL",
+  "status": "ready",
+  "remediation": {
+    "func": "Constant\/Issue",
+    "constantCost": "5min"
+  },
+  "tags": [
+    "convention",
+    "error-handling",
+    "pitfall"
+  ],
+  "defaultSeverity": "Major",
+  "ruleSpecification": "RSPEC-2166",
+  "sqKey": "S2166",
+  "scope": "Main",
+  "quickfix": "unknown"
+}

analyzers/rspec/cs/Sonar_way_profile.json

@@ -62,6 +62,7 @@
     "S2114",
     "S2115",
     "S2123",
+    "S2166",
     "S2178",
     "S2183",
     "S2184",

analyzers/rspec/vbnet/S2166_vb.net.html

@@ -0,0 +1,35 @@
+<p>Clear, communicative naming is important in code. It helps maintainers and API users understand the intentions for and uses of a unit of code.
+Using "exception" in the name of a class that does not extend <code>Exception</code> or one of its subclasses is a clear violation of the expectation
+that a class' name will indicate what it is and/or does.</p>
+<h2>Noncompliant Code Example</h2>
+<pre>
+Public Class FruitException ' Noncompliant - this has nothing to do with Exception
+    Private expected As Fruit
+    Private unusualCharacteristics As String
+    Private appropriateForCommercialExploitation As Boolean
+    ' ...
+End Class
+
+Public Class CarException ' Noncompliant - does not derive from any Exception-based class
+    Public Sub New(ByVal message As String, ByVal inner As Exception)
+        ' ...
+    End Sub
+End Class
+</pre>
+<h2>Compliant Solution</h2>
+<pre>
+Public Class FruitSport ' Compliant - class name does not end with 'Exception'
+    Private expected As Fruit
+    Private unusualCharacteristics As String
+    Private appropriateForCommercialExploitation As Boolean
+    ' ...
+End Class
+
+Public Class CarException Inherits Exception ' Compliant - correctly extends System.Exception
+    Public Sub New(ByVal message As String, ByVal inner As Exception)
+        MyBase.New(message, inner)
+        ' ...
+    End Sub
+End Class
+</pre>
+

analyzers/rspec/vbnet/S2166_vb.net.json

@@ -0,0 +1,19 @@
+{
+  "title": "Classes named like \"Exception\" should extend \"Exception\" or a subclass",
+  "type": "CODE_SMELL",
+  "status": "ready",
+  "remediation": {
+    "func": "Constant\/Issue",
+    "constantCost": "5min"
+  },
+  "tags": [
+    "convention",
+    "error-handling",
+    "pitfall"
+  ],
+  "defaultSeverity": "Major",
+  "ruleSpecification": "RSPEC-2166",
+  "sqKey": "S2166",
+  "scope": "Main",
+  "quickfix": "unknown"
+}

analyzers/rspec/vbnet/Sonar_way_profile.json

@@ -38,6 +38,7 @@
     "S1940",
     "S2068",
     "S2077",
+    "S2166",
     "S2178",
     "S2222",
     "S2225",

analyzers/src/SonarAnalyzer.CSharp/Rules/ClassNamedException.cs

@@ -0,0 +1,29 @@
+/*
+ * SonarAnalyzer for .NET
+ * Copyright (C) 2015-2023 SonarSource SA
+ * mailto: contact AT sonarsource DOT com
+ *
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU Lesser General Public
+ * License as published by the Free Software Foundation; either
+ * version 3 of the License, or (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+ * Lesser General Public License for more details.
+ *
+ * You should have received a copy of the GNU Lesser General Public License
+ * along with this program; if not, write to the Free Software Foundation,
+ * Inc., 51 Franklin Street, Fifth Floor, Boston, MA  02110-1301, USA.
+ */
+
+using Microsoft.CodeAnalysis.CSharp;
+
+namespace SonarAnalyzer.Rules.CSharp;
+
+[DiagnosticAnalyzer(LanguageNames.CSharp)]
+public sealed class ClassNamedException : ClassNamedExceptionBase<SyntaxKind>
+{
+    protected override ILanguageFacade<SyntaxKind> Language => CSharpFacade.Instance;
+}

analyzers/src/SonarAnalyzer.Common/Rules/ClassNamedExceptionBase.cs

@@ -0,0 +1,48 @@
+/*
+ * SonarAnalyzer for .NET
+ * Copyright (C) 2015-2023 SonarSource SA
+ * mailto: contact AT sonarsource DOT com
+ *
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU Lesser General Public
+ * License as published by the Free Software Foundation; either
+ * version 3 of the License, or (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+ * Lesser General Public License for more details.
+ *
+ * You should have received a copy of the GNU Lesser General Public License
+ * along with this program; if not, write to the Free Software Foundation,
+ * Inc., 51 Franklin Street, Fifth Floor, Boston, MA  02110-1301, USA.
+ */
+
+namespace SonarAnalyzer.Rules;
+
+public abstract class ClassNamedExceptionBase<TSyntaxKind> : SonarDiagnosticAnalyzer<TSyntaxKind>
+    where TSyntaxKind : struct
+{
+    private const string DiagnosticId = "S2166";
+
+    protected override string MessageFormat => "Rename this class to remove \"(e|E)xception\" or correct its inheritance.";
+
+    protected ClassNamedExceptionBase() : base(DiagnosticId) { }
+
+    protected override void Initialize(SonarAnalysisContext context) =>
+        context.RegisterNodeAction(
+        Language.GeneratedCodeRecognizer,
+        c =>
+        {
+            if (Language.Syntax.NodeIdentifier(c.Node) is { IsMissing: false } classIdentifier
+             && classIdentifier.ValueText.EndsWith("Exception", StringComparison.InvariantCultureIgnoreCase)
+             && c.SemanticModel.GetDeclaredSymbol(c.Node) is INamedTypeSymbol { } classSymbol
+             && !classSymbol.IsStatic
+             && !classSymbol.DerivesFrom(KnownType.System_Exception))
+            {
+                c.ReportIssue(Diagnostic.Create(Rule, classIdentifier.GetLocation()));
+            }
+        },
+        Language.SyntaxKind.ClassDeclaration);
+
+}

analyzers/src/SonarAnalyzer.VisualBasic/Rules/ClassNamedException.cs

@@ -0,0 +1,27 @@
+/*
+ * SonarAnalyzer for .NET
+ * Copyright (C) 2015-2023 SonarSource SA
+ * mailto: contact AT sonarsource DOT com
+ *
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU Lesser General Public
+ * License as published by the Free Software Foundation; either
+ * version 3 of the License, or (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+ * Lesser General Public License for more details.
+ *
+ * You should have received a copy of the GNU Lesser General Public License
+ * along with this program; if not, write to the Free Software Foundation,
+ * Inc., 51 Franklin Street, Fifth Floor, Boston, MA  02110-1301, USA.
+ */
+
+namespace SonarAnalyzer.Rules.VisualBasic;
+
+[DiagnosticAnalyzer(LanguageNames.VisualBasic)]
+public sealed class ClassNamedException : ClassNamedExceptionBase<SyntaxKind>
+{
+    protected override ILanguageFacade<SyntaxKind> Language => VisualBasicFacade.Instance;
+}

analyzers/tests/SonarAnalyzer.UnitTest/PackagingTests/RuleTypeMappingCS.cs

@@ -2090,7 +2090,7 @@ internal static class RuleTypeMappingCS
         // ["S2163"],
         // ["S2164"],
         // ["S2165"],
-        // ["S2166"],
+        ["S2166"] = "CODE_SMELL",
         // ["S2167"],
         // ["S2168"],
         // ["S2169"],

analyzers/tests/SonarAnalyzer.UnitTest/PackagingTests/RuleTypeMappingVB.cs

@@ -2090,7 +2090,7 @@ internal static class RuleTypeMappingVB
         // ["S2163"],
         // ["S2164"],
         // ["S2165"],
-        // ["S2166"],
+        ["S2166"] = "CODE_SMELL",
         // ["S2167"],
         // ["S2168"],
         // ["S2169"],

analyzers/tests/SonarAnalyzer.UnitTest/Rules/ClassNamedExceptionTest.cs

@@ -0,0 +1,53 @@
+/*
+ * SonarAnalyzer for .NET
+ * Copyright (C) 2015-2023 SonarSource SA
+ * mailto: contact AT sonarsource DOT com
+ *
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU Lesser General Public
+ * License as published by the Free Software Foundation; either
+ * version 3 of the License, or (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+ * Lesser General Public License for more details.
+ *
+ * You should have received a copy of the GNU Lesser General Public License
+ * along with this program; if not, write to the Free Software Foundation,
+ * Inc., 51 Franklin Street, Fifth Floor, Boston, MA  02110-1301, USA.
+ */
+
+
+using CS = SonarAnalyzer.Rules.CSharp;
+using VB = SonarAnalyzer.Rules.VisualBasic;
+
+namespace SonarAnalyzer.UnitTest.Rules;
+
+[TestClass]
+public class ClassNamedExceptionTest
+{
+    private readonly VerifierBuilder builderCS = new VerifierBuilder<CS.ClassNamedException>();
+    private readonly VerifierBuilder builderVB = new VerifierBuilder<VB.ClassNamedException>();
+
+    [TestMethod]
+    public void ClassNamedException_CS() => builderCS
+        .AddPaths("ClassNamedException.cs")
+        .Verify();
+
+    [TestMethod]
+    public void ClassNamedException_FromCSharp9() => builderCS
+        .AddPaths("ClassNamedException.CSharp9.cs")
+        .WithOptions(ParseOptionsHelper.FromCSharp9)
+        .Verify();
+
+    [TestMethod]
+    public void ClassNamedException_FromCSharp10() => builderCS
+        .AddPaths("ClassNamedException.CSharp10.cs")
+        .WithOptions(ParseOptionsHelper.FromCSharp10)
+        .Verify();
+
+    [TestMethod]
+    public void ClassNamedException_VB() =>
+        builderVB.AddPaths("ClassNamedException.vb").Verify();
+}

analyzers/tests/SonarAnalyzer.UnitTest/TestCases/ClassNamedException.CSharp10.cs

@@ -0,0 +1 @@
+record struct RecordStructException { } // Compliant - record structs cannot inherit from Exception

analyzers/tests/SonarAnalyzer.UnitTest/TestCases/ClassNamedException.CSharp9.cs

@@ -0,0 +1 @@
+record RecordException { } // Compliant - records cannot inherit from Exception

analyzers/tests/SonarAnalyzer.UnitTest/TestCases/ClassNamedException.cs

@@ -0,0 +1,32 @@
+using System;
+
+class CustomException { }                                        // Noncompliant {{Rename this class to remove "(e|E)xception" or correct its inheritance.}}
+//    ^^^^^^^^^^^^^^^
+class Customexception { }                                        // Noncompliant
+class CustomEXCEPTION { }                                        // Noncompliant
+
+class ExceptionHandler { }                                       // Compliant - "Exception" is not at end of the name of the class
+class SimpleClass { }
+class SimpleExceptionClass: Exception { }
+
+class OuterClass
+{
+    class InnerException { }                                     // Noncompliant
+}
+
+interface IEmptyInterfaceException { }                           // Compliant - interfaces cannot inherit from Exception
+struct StructException { }                                       // Compliant - structs cannot inherit from Exception
+enum EnumException { }                                           // Compliant - enums cannot inherit from Exception
+
+class ExtendsException: Exception { }                            // Compliant - direct subclass of Exception
+class ImplementsAnInterfaceAndExtendsException: Exception, IEmptyInterfaceException { }
+class ExtendsNullReferenceException : NullReferenceException { } // Compliant - indirect subclass of Exception
+
+class ExtendsCustomException: CustomException { }                // Noncompliant - CustomException is not an Exception subclass
+
+partial class PartialClassDoesNotExtendException { }             // Noncompliant
+
+partial class PartialClassExtendsException { }                   // Compliant - the other part of the class extends Exception
+partial class PartialClassExtendsException: Exception { }
+
+static class StaticException { }                                 // Compliant - static classes cannot inherit from Exception