Merge pull request #32876 from alrz/fix-assert

Fix assertion in UsePatternMatching analyzer

src/EditorFeatures/CSharpTest/UsePatternMatching/CSharpAsAndNullCheckTests.cs

@@ -99,6 +99,39 @@ void M()
 }");
         }
 
+        [Fact, Trait(Traits.Feature, Traits.Features.CodeActionsInlineTypeCheck)]
+        public async Task TestInSwitchSection()
+        {
+            await TestInRegularAndScriptAsync(
+@"class C
+{
+    void M()
+    {
+        switch (o)
+        {
+            default:
+                [|var|] x = o as string;
+                if (x != null)
+                {
+                }
+        }
+    }
+}",
+@"class C
+{
+    void M()
+    {
+        switch (o)
+        {
+            default:
+                if (o is string x)
+                {
+                }
+        }
+    }
+}");
+        }
+
         [Fact, Trait(Traits.Feature, Traits.Features.CodeActionsInlineTypeCheck)]
         public async Task TestMissingOnNonDeclaration()
         {

src/Features/CSharp/Portable/UsePatternMatching/CSharpAsAndNullCheckDiagnosticAnalyzer.Analyzer.cs

@@ -34,7 +34,7 @@ internal partial class CSharpAsAndNullCheckDiagnosticAnalyzer
                 Debug.Assert(comparison != null);
                 Debug.Assert(operand != null);
                 Debug.Assert(localStatement.IsKind(SyntaxKind.LocalDeclarationStatement));
-                Debug.Assert(enclosingBlock.IsKind(SyntaxKind.Block));
+                Debug.Assert(enclosingBlock.IsKind(SyntaxKind.Block, SyntaxKind.SwitchSection));
 
                 _semanticModel = semanticModel;
                 _comparison = comparison;