From 5c8e7e33f8667eb4fccf318ae83bfad0f7ad2ef4 Mon Sep 17 00:00:00 2001
From: Martin Strecker
 <103252490+martin-strecker-sonarsource@users.noreply.github.com>
Date: Tue, 28 Feb 2023 15:28:51 +0100
Subject: [PATCH] Old SE: Handle unsupported syntax gracefully (#6768)

---
 .../Sonar/SonarExplodedGraph.cs               |  4 ++-
 .../CFG/Sonar/SonarControlFlowGraphTest.cs    | 16 ++++++++++++
 .../Sonar/SonarExplodedGraphTest.cs           | 22 +++++++++++++++-
 .../Sonar/NullPointerDereference.CSharp11.cs  | 25 +++++++++++++++++++
 4 files changed, 65 insertions(+), 2 deletions(-)

diff --git a/analyzers/src/SonarAnalyzer.CSharp/SymbolicExecution/Sonar/SonarExplodedGraph.cs b/analyzers/src/SonarAnalyzer.CSharp/SymbolicExecution/Sonar/SonarExplodedGraph.cs
index 50ff53fd26a..d677065704e 100644
--- a/analyzers/src/SonarAnalyzer.CSharp/SymbolicExecution/Sonar/SonarExplodedGraph.cs
+++ b/analyzers/src/SonarAnalyzer.CSharp/SymbolicExecution/Sonar/SonarExplodedGraph.cs
@@ -577,7 +577,9 @@ protected override void VisitInstruction(ExplodedGraphNode node)
                     break;
 
                 default:
-                    throw new NotSupportedException($"{instruction.Kind()}");
+                    // Not Supported
+                    // Do nothing
+                    break;
             }
 
             newProgramState = InvokeChecks(newProgramState, (ps, check) => check.PostProcessInstruction(node.ProgramPoint, ps));
diff --git a/analyzers/tests/SonarAnalyzer.UnitTest/CFG/Sonar/SonarControlFlowGraphTest.cs b/analyzers/tests/SonarAnalyzer.UnitTest/CFG/Sonar/SonarControlFlowGraphTest.cs
index a10a3d0447e..10db0c26c67 100644
--- a/analyzers/tests/SonarAnalyzer.UnitTest/CFG/Sonar/SonarControlFlowGraphTest.cs
+++ b/analyzers/tests/SonarAnalyzer.UnitTest/CFG/Sonar/SonarControlFlowGraphTest.cs
@@ -4141,6 +4141,22 @@ public void Cfg_OrPattern_InIf_IsNotSupported()
             exception.Message.Should().Be("OrPattern");
         }
 
+        [TestMethod]
+        public void Cfg_ParenthesizedPattern_InIf_IsNotSupported()
+        {
+            var exception = Assert.ThrowsException<NotSupportedException>(() => Build(@"if (tainted is (string s)) { }"));
+
+            exception.Message.Should().Be("ParenthesizedPattern");
+        }
+
+        [TestMethod]
+        public void Cfg_ListPattern_InIf_IsNotSupported()
+        {
+            var exception = Assert.ThrowsException<NotSupportedException>(() => Build(@"if (tainted is []) { }"));
+
+            exception.Message.Should().Be("ListPattern");
+        }
+
         [TestMethod]
         public void Cfg_Switch_Patterns_NoDefault()
         {
diff --git a/analyzers/tests/SonarAnalyzer.UnitTest/SymbolicExecution/Sonar/SonarExplodedGraphTest.cs b/analyzers/tests/SonarAnalyzer.UnitTest/SymbolicExecution/Sonar/SonarExplodedGraphTest.cs
index e3bb80b6cb0..4ab0ad9c7a6 100644
--- a/analyzers/tests/SonarAnalyzer.UnitTest/SymbolicExecution/Sonar/SonarExplodedGraphTest.cs
+++ b/analyzers/tests/SonarAnalyzer.UnitTest/SymbolicExecution/Sonar/SonarExplodedGraphTest.cs
@@ -28,7 +28,6 @@
 using SonarAnalyzer.LiveVariableAnalysis.CSharp;
 using SonarAnalyzer.SymbolicExecution.Constraints;
 using SonarAnalyzer.SymbolicExecution.Sonar;
-using SonarAnalyzer.SymbolicExecution.Sonar.Constraints;
 using SonarAnalyzer.UnitTest.CFG.Sonar;
 using SonarAnalyzer.UnitTest.Helpers;
 
@@ -901,6 +900,27 @@ public void ExplodedGraph_IsPattern_WithPositionalPattern()
             context.WalkWithInstructions(4);
         }
 
+        [DataTestMethod]
+        [DataRow("int")]
+        [DataRow("(string s)")]
+        [DataRow("1 or 2")]
+        [DataRow("1 and 2")]
+        [DataRow("not 1")]
+        [DataRow("> 5")]
+        [DataRow("[] empty")]
+        public void ExplodedGraph_SwitchStatement_UnsupportedPatternKinds(string pattern)
+        {
+            var testInput = $$"""
+                switch (new object())
+                {
+                    case {{pattern}}: break;
+                }
+                """;
+            var context = new ExplodedGraphContext(testInput);
+            var walk = () => context.WalkWithInstructions(2);
+            walk.Should().Throw<Exception>().WithMessage("Expected NumberOfExitBlockReached to be 1, but found 0.");
+        }
+
         [TestMethod]
         public void ExplodedGraph_SwitchExpressionVisit()
         {
diff --git a/analyzers/tests/SonarAnalyzer.UnitTest/TestCases/SymbolicExecution/Sonar/NullPointerDereference.CSharp11.cs b/analyzers/tests/SonarAnalyzer.UnitTest/TestCases/SymbolicExecution/Sonar/NullPointerDereference.CSharp11.cs
index c6f4e7e4528..9d0bf1f6501 100644
--- a/analyzers/tests/SonarAnalyzer.UnitTest/TestCases/SymbolicExecution/Sonar/NullPointerDereference.CSharp11.cs
+++ b/analyzers/tests/SonarAnalyzer.UnitTest/TestCases/SymbolicExecution/Sonar/NullPointerDereference.CSharp11.cs
@@ -19,4 +19,29 @@ public void ListPattern(object[] objects)
             }
         }
     }
+
+    // https://github.com/SonarSource/sonar-dotnet/issues/6766
+    public class Repo_6766
+    {
+        public void SwitchCasePattern(object o, object[] array)
+        {
+            switch (o)
+            {
+                case (1 or 2):                        // Parenthesized
+                case 3 or 4:                          // Binary
+                case > 5:                             // Relational
+                case char:                            // Type
+                case Exception { Message.Length: 1 }: // Recursive
+                case (int _, int _):                  // Recursive
+                case not "":                          // Unary
+                    break;
+            }
+            switch (array)
+            {
+                case []:         // list pattern
+                case [1, .., 2]: // list pattern with slice
+                    break;
+            }
+        }
+    }
 }