Fix S112 FN: When using null-coalesce operator (#7911)

analyzers/its/expected/Automapper/AutoMapper--net461-S112.json

@@ -0,0 +1,17 @@
+{
+"issues":  [
+{
+"id":  "S112",
+"message":  "'System.NullReferenceException' should not be thrown by user code.",
+"location":  {
+"uri":  "https://github.com/SonarSource/sonar-dotnet/blob/master/analyzers/its/sources/AutoMapper/src/AutoMapper/Mapper.cs#L151",
+"region":  {
+"startLine":  151,
+"startColumn":  117,
+"endLine":  151,
+"endColumn":  164
+}
+}
+}
+]
+}

analyzers/its/expected/Automapper/AutoMapper--netstandard2.0-S112.json

@@ -0,0 +1,17 @@
+{
+"issues":  [
+{
+"id":  "S112",
+"message":  "'System.NullReferenceException' should not be thrown by user code.",
+"location":  {
+"uri":  "https://github.com/SonarSource/sonar-dotnet/blob/master/analyzers/its/sources/AutoMapper/src/AutoMapper/Mapper.cs#L151",
+"region":  {
+"startLine":  151,
+"startColumn":  117,
+"endLine":  151,
+"endColumn":  164
+}
+}
+}
+]
+}

analyzers/its/expected/Net5/Net5--net5.0-S112.json

@@ -12,6 +12,19 @@
 "endColumn":  34
 }
 }
+},
+{
+"id":  "S112",
+"message":  "'System.Exception' should not be thrown by user code.",
+"location":  {
+"uri":  "https://github.com/SonarSource/sonar-dotnet/blob/master/analyzers/its/sources/Net5/Net5/S3877.cs#L15",
+"region":  {
+"startLine":  15,
+"startColumn":  44,
+"endLine":  15,
+"endColumn":  59
+}
+}
 }
 ]
 }

analyzers/its/expected/akka.net/Akka.Benchmarks--netcoreapp3.1-S112.json

@@ -0,0 +1,17 @@
+{
+"issues":  [
+{
+"id":  "S112",
+"message":  "'System.Exception' should not be thrown by user code.",
+"location":  {
+"uri":  "https://github.com/SonarSource/sonar-dotnet/blob/master/analyzers/its/sources/akka.net/src/benchmark/Akka.Benchmarks/IO/TcpOperationsBenchmarks.cs#L149",
+"region":  {
+"startLine":  149,
+"startColumn":  55,
+"endLine":  149,
+"endColumn":  89
+}
+}
+}
+]
+}

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

@@ -18,23 +18,16 @@
  * Inc., 51 Franklin Street, Fifth Floor, Boston, MA  02110-1301, USA.
  */
 
-namespace SonarAnalyzer.Rules.CSharp
-{
-    [DiagnosticAnalyzer(LanguageNames.CSharp)]
-    public sealed class ThrowReservedExceptions : ThrowReservedExceptionsBase
-    {
-        private static readonly DiagnosticDescriptor rule =
-            DescriptorFactory.Create(DiagnosticId, MessageFormat);
-        public override ImmutableArray<DiagnosticDescriptor> SupportedDiagnostics { get; } = ImmutableArray.Create(rule);
+namespace SonarAnalyzer.Rules.CSharp;
 
-        protected override void Initialize(SonarAnalysisContext context)
-        {
-            context.RegisterNodeAction(
-                c => ReportReservedExceptionCreation(c, ((ThrowStatementSyntax)c.Node).Expression),
-                SyntaxKind.ThrowStatement);
-        }
+[DiagnosticAnalyzer(LanguageNames.CSharp)]
+public sealed class ThrowReservedExceptions : ThrowReservedExceptionsBase<SyntaxKind>
+{
+    protected override ILanguageFacade<SyntaxKind> Language => CSharpFacade.Instance;
 
-        protected override bool IsObjectCreation(SyntaxNode throwStatementExpression) =>
-            throwStatementExpression.IsKind(SyntaxKind.ObjectCreationExpression);
+    protected override void Initialize(SonarAnalysisContext context)
+    {
+        context.RegisterNodeAction(c => Process(c, ((ThrowStatementSyntax)c.Node).Expression), SyntaxKind.ThrowStatement);
+        context.RegisterNodeAction(c => Process(c, ((ThrowExpressionSyntaxWrapper)c.Node).Expression), SyntaxKindEx.ThrowExpression);
     }
 }

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

@@ -18,40 +18,35 @@
  * Inc., 51 Franklin Street, Fifth Floor, Boston, MA  02110-1301, USA.
  */
 
-namespace SonarAnalyzer.Rules
+namespace SonarAnalyzer.Rules;
+
+public abstract class ThrowReservedExceptionsBase<TSyntaxKind> : SonarDiagnosticAnalyzer<TSyntaxKind>
+    where TSyntaxKind : struct
 {
-    public abstract class ThrowReservedExceptionsBase : SonarDiagnosticAnalyzer
-    {
-        internal const string DiagnosticId = "S112";
-        internal const string MessageFormat = "'{0}' should not be thrown by user code.";
+    protected const string DiagnosticId = "S112";
 
-        internal static readonly ImmutableArray<KnownType> ReservedExceptionTypeNames =
-            ImmutableArray.Create(
-                KnownType.System_Exception,
-                KnownType.System_ApplicationException,
-                KnownType.System_SystemException,
-                KnownType.System_ExecutionEngineException,
-                KnownType.System_IndexOutOfRangeException,
-                KnownType.System_NullReferenceException,
-                KnownType.System_OutOfMemoryException
-            );
+    private readonly ImmutableArray<KnownType> reservedExceptions = ImmutableArray.Create(
+        KnownType.System_Exception,
+        KnownType.System_ApplicationException,
+        KnownType.System_SystemException,
+        KnownType.System_ExecutionEngineException,
+        KnownType.System_IndexOutOfRangeException,
+        KnownType.System_NullReferenceException,
+        KnownType.System_OutOfMemoryException);
 
-        protected void ReportReservedExceptionCreation(SonarSyntaxNodeReportingContext context,
-            SyntaxNode throwStatementExpression)
-        {
-            if (throwStatementExpression == null ||
-                !IsObjectCreation(throwStatementExpression))
-            {
-                return;
-            }
+    protected override string MessageFormat => "'{0}' should not be thrown by user code.";
 
-            var expressionType = context.SemanticModel.GetTypeInfo(throwStatementExpression).Type;
-            if (expressionType.IsAny(ReservedExceptionTypeNames))
+    protected ThrowReservedExceptionsBase() : base(DiagnosticId) { }
+
+    protected void Process(SonarSyntaxNodeReportingContext context, SyntaxNode thrownExpression)
+    {
+        if (thrownExpression is not null && Language.Syntax.IsAnyKind(thrownExpression, Language.SyntaxKind.ObjectCreationExpressions))
+        {
+            var expressionType = context.SemanticModel.GetTypeInfo(thrownExpression).Type;
+            if (expressionType.IsAny(reservedExceptions))
             {
-                context.ReportIssue(Diagnostic.Create(SupportedDiagnostics[0], throwStatementExpression.GetLocation(), expressionType.ToDisplayString()));
+                context.ReportIssue(Diagnostic.Create(Rule, thrownExpression.GetLocation(), expressionType.ToDisplayString()));
             }
         }
-
-        protected abstract bool IsObjectCreation(SyntaxNode throwStatementExpression);
     }
 }

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

@@ -18,24 +18,13 @@
  * Inc., 51 Franklin Street, Fifth Floor, Boston, MA  02110-1301, USA.
  */
 
-namespace SonarAnalyzer.Rules.VisualBasic
-{
-    [DiagnosticAnalyzer(LanguageNames.VisualBasic)]
-    public sealed class ThrowReservedExceptions : ThrowReservedExceptionsBase
-    {
-        private static readonly DiagnosticDescriptor rule =
-            DescriptorFactory.Create(DiagnosticId, MessageFormat);
-
-        public override ImmutableArray<DiagnosticDescriptor> SupportedDiagnostics { get; } = ImmutableArray.Create(rule);
+namespace SonarAnalyzer.Rules.VisualBasic;
 
-        protected override void Initialize(SonarAnalysisContext context)
-        {
-            context.RegisterNodeAction(
-                c => ReportReservedExceptionCreation(c, ((ThrowStatementSyntax)c.Node).Expression),
-                SyntaxKind.ThrowStatement);
-        }
+[DiagnosticAnalyzer(LanguageNames.VisualBasic)]
+public sealed class ThrowReservedExceptions : ThrowReservedExceptionsBase<SyntaxKind>
+{
+    protected override ILanguageFacade<SyntaxKind> Language => VisualBasicFacade.Instance;
 
-        protected override bool IsObjectCreation(SyntaxNode throwStatementExpression) =>
-           throwStatementExpression.IsKind(SyntaxKind.ObjectCreationExpression);
-    }
+    protected override void Initialize(SonarAnalysisContext context) =>
+        context.RegisterNodeAction(c => Process(c, ((ThrowStatementSyntax)c.Node).Expression), SyntaxKind.ThrowStatement);
 }

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

@@ -21,17 +21,22 @@
 using CS = SonarAnalyzer.Rules.CSharp;
 using VB = SonarAnalyzer.Rules.VisualBasic;
 
-namespace SonarAnalyzer.UnitTest.Rules
+namespace SonarAnalyzer.UnitTest.Rules;
+
+[TestClass]
+public class ThrowReservedExceptionsTest
 {
-    [TestClass]
-    public class ThrowReservedExceptionsTest
-    {
-        [TestMethod]
-        public void ThrowReservedExceptions_CSharp() =>
-            new VerifierBuilder<CS.ThrowReservedExceptions>().AddPaths("ThrowReservedExceptions.cs").Verify();
+    private readonly VerifierBuilder builderCS = new VerifierBuilder<CS.ThrowReservedExceptions>();
+
+    [TestMethod]
+    public void ThrowReservedExceptions_CS() =>
+        builderCS.AddPaths("ThrowReservedExceptions.cs").Verify();
+
+    [TestMethod]
+    public void ThrowReservedExceptions_CSharp8() =>
+        builderCS.AddPaths("ThrowReservedExceptions.CSharp8.cs").WithOptions(ParseOptionsHelper.FromCSharp8).Verify();
 
-        [TestMethod]
-        public void ThrowReservedExceptions_VisualBasic() =>
-            new VerifierBuilder<VB.ThrowReservedExceptions>().AddPaths("ThrowReservedExceptions.vb").Verify();
-    }
+    [TestMethod]
+    public void ThrowReservedExceptions_VB() =>
+        new VerifierBuilder<VB.ThrowReservedExceptions>().AddPaths("ThrowReservedExceptions.vb").Verify();
 }

analyzers/tests/SonarAnalyzer.UnitTest/TestCases/ThrowReservedExceptions.CSharp8.cs

@@ -0,0 +1,17 @@
+using System;
+
+public class Sample
+{
+    public void NullCoalesce(object arg)
+    {
+        _ = arg ?? throw new Exception();   // Noncompliant
+        //               ^^^^^^^^^^^^^^^
+
+        _ = arg switch
+        {
+            string s => s,
+            _ => throw new Exception()      // Noncompliant
+            //         ^^^^^^^^^^^^^^^
+        };
+    }
+}

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

@@ -1,47 +1,49 @@
 using System;
 
-namespace SonarAnalyzer.UnitTest.TestCases
+public class ThrowReservedExceptions
 {
-    public class ThrowReservedExceptions
+    public void Method1()
     {
-        public void Method1()
-        {
-            throw new Exception(); // Noncompliant {{'System.Exception' should not be thrown by user code.}}
-//                ^^^^^^^^^^^^^^^
-
-            throw new ApplicationException(); // Noncompliant {{'System.ApplicationException' should not be thrown by user code.}}
-//                ^^^^^^^^^^^^^^^^^^^^^^^^^^
+        throw new Exception();                  // Noncompliant {{'System.Exception' should not be thrown by user code.}}
+//            ^^^^^^^^^^^^^^^
 
-            throw new SystemException(); // Noncompliant {{'System.SystemException' should not be thrown by user code.}}
-//                ^^^^^^^^^^^^^^^^^^^^^
+        throw new ApplicationException();       // Noncompliant {{'System.ApplicationException' should not be thrown by user code.}}
+//            ^^^^^^^^^^^^^^^^^^^^^^^^^^
 
-            throw new ExecutionEngineException(); // Noncompliant {{'System.ExecutionEngineException' should not be thrown by user code.}}
-//                ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
+        throw new SystemException();            // Noncompliant {{'System.SystemException' should not be thrown by user code.}}
+//            ^^^^^^^^^^^^^^^^^^^^^
 
-            throw new IndexOutOfRangeException(); // Noncompliant {{'System.IndexOutOfRangeException' should not be thrown by user code.}}
-//                ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
+        throw new ExecutionEngineException();   // Noncompliant {{'System.ExecutionEngineException' should not be thrown by user code.}}
+//            ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
 
-            throw new NullReferenceException(); // Noncompliant {{'System.NullReferenceException' should not be thrown by user code.}}
-//                ^^^^^^^^^^^^^^^^^^^^^^^^^^^^
+        throw new IndexOutOfRangeException();   // Noncompliant {{'System.IndexOutOfRangeException' should not be thrown by user code.}}
+//            ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
 
-            throw new OutOfMemoryException(); // Noncompliant {{'System.OutOfMemoryException' should not be thrown by user code.}}
-//                ^^^^^^^^^^^^^^^^^^^^^^^^^^
+        throw new NullReferenceException();     // Noncompliant {{'System.NullReferenceException' should not be thrown by user code.}}
+//            ^^^^^^^^^^^^^^^^^^^^^^^^^^^^
 
-            var e = new OutOfMemoryException(); // Compliant
+        throw new OutOfMemoryException();       // Noncompliant {{'System.OutOfMemoryException' should not be thrown by user code.}}
+//            ^^^^^^^^^^^^^^^^^^^^^^^^^^
 
-            throw new ArgumentNullException(); // Compliant
+        var e = new OutOfMemoryException(); // Compliant
+        throw new ArgumentNullException();  // Compliant
 
-            OutOfMemoryException e1 = (OutOfMemoryException)new ArgumentException(); // Error [CS0030] - cannot cast
+        OutOfMemoryException e1 = (OutOfMemoryException)new ArgumentException(); // Error [CS0030] - cannot cast
 
-            try
-            {
-                var a = new int[0];
-                Console.WriteLine(a[1]); // Throw exception
-            }
-            catch (IndexOutOfRangeException)
-            {
-                throw; // Compliant
-            }
+        try
+        {
+            var a = new int[0];
+            Console.WriteLine(a[1]); // Throw exception
+        }
+        catch (IndexOutOfRangeException)
+        {
+            throw; // Compliant
         }
     }
+
+    public void Arrow() =>
+        throw new Exception();          // Noncompliant
+
+    public Action Lambda() =>
+        () => throw new Exception();    // Noncompliant
 }

analyzers/tests/SonarAnalyzer.UnitTest/TestCases/ThrowReservedExceptions.vb

@@ -1,32 +1,28 @@
-Imports System
+Public Class ThrowReservedExceptions
+    Public Sub Method1()
+        Throw New Exception()                   ' Noncompliant {{'System.Exception' should not be thrown by user code.}}
+        '     ^^^^^^^^^^^^^^^
+        Throw New ApplicationException()        ' Noncompliant {{'System.ApplicationException' should not be thrown by user code.}}
+        '     ^^^^^^^^^^^^^^^^^^^^^^^^^^
+        Throw New SystemException()             ' Noncompliant {{'System.SystemException' should not be thrown by user code.}}
+        '     ^^^^^^^^^^^^^^^^^^^^^
+        Throw New ExecutionEngineException()    ' Noncompliant {{'System.ExecutionEngineException' should not be thrown by user code.}}
+        '     ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
+        Throw New IndexOutOfRangeException()    ' Noncompliant {{'System.IndexOutOfRangeException' should not be thrown by user code.}}
+        '     ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
+        Throw New NullReferenceException()      ' Noncompliant {{'System.NullReferenceException' should not be thrown by user code.}}
+        '     ^^^^^^^^^^^^^^^^^^^^^^^^^^^^
+        Throw New OutOfMemoryException()        ' Noncompliant {{'System.OutOfMemoryException' should not be thrown by user code.}}
+        '     ^^^^^^^^^^^^^^^^^^^^^^^^^^
+        Dim e = New OutOfMemoryException()  ' Compliant
+        Throw New ArgumentNullException()   ' Compliant
 
-Namespace SonarAnalyzer.UnitTest.TestCases
-    Public Class ThrowReservedExceptions
-        Public Sub Method1()
-            Throw New Exception() ' Noncompliant {{'System.Exception' should not be thrown by user code.}}
-'                 ^^^^^^^^^^^^^^^
-            Throw New ApplicationException() ' Noncompliant {{'System.ApplicationException' should not be thrown by user code.}}
-'                 ^^^^^^^^^^^^^^^^^^^^^^^^^^
-            Throw New SystemException() ' Noncompliant {{'System.SystemException' should not be thrown by user code.}}
-'                 ^^^^^^^^^^^^^^^^^^^^^
-            Throw New ExecutionEngineException() ' Noncompliant {{'System.ExecutionEngineException' should not be thrown by user code.}}
-'                 ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
-            Throw New IndexOutOfRangeException() ' Noncompliant {{'System.IndexOutOfRangeException' should not be thrown by user code.}}
-'                 ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
-            Throw New NullReferenceException() ' Noncompliant {{'System.NullReferenceException' should not be thrown by user code.}}
-'                 ^^^^^^^^^^^^^^^^^^^^^^^^^^^^
-            Throw New OutOfMemoryException() ' Noncompliant {{'System.OutOfMemoryException' should not be thrown by user code.}}
-'                 ^^^^^^^^^^^^^^^^^^^^^^^^^^
-            Dim e = New OutOfMemoryException() ' Compliant
-            Throw New ArgumentNullException() ' Compliant
-
-            Try
-                Dim a = New Integer(-1) {}
-                ' Throw exception
-                Console.WriteLine(a(1))
-            Catch generatedExceptionName As IndexOutOfRangeException ' Compliant
-                Throw
-            End Try
-        End Sub
-    End Class
-End Namespace
+        Try
+            Dim a = New Integer(-1) {}
+            ' Throw exception
+            Console.WriteLine(a(1))
+        Catch generatedExceptionName As IndexOutOfRangeException ' Compliant
+            Throw
+        End Try
+    End Sub
+End Class