Avoid deep recursion in NullabilityRewriter.VisitBinaryPattern

src/Compilers/CSharp/Portable/BoundTree/BoundNodes.xml

@@ -2529,7 +2529,7 @@
            Left.InputType is the InputType 
            Right.InputType is the Left.NarrowedType 
   -->
-  <Node Name="BoundBinaryPattern" Base="BoundPattern" HasValidate="true">
+  <Node Name="BoundBinaryPattern" Base="BoundPattern" HasValidate="true" SkipInNullabilityRewriter="true">
     <Field Name="Disjunction" Type="bool"/>
     <Field Name="Left" Type="BoundPattern"/>
     <Field Name="Right" Type="BoundPattern"/>

src/Compilers/CSharp/Portable/BoundTree/NullabilityRewriter.cs

@@ -134,6 +134,41 @@ private BoundNode VisitBinaryOperatorBase(BoundBinaryOperatorBase binaryOperator
             return currentBinary!;
         }
 
+        public override BoundNode? VisitBinaryPattern(BoundBinaryPattern node)
+        {
+            // Use an explicit stack to avoid blowing the managed stack when visiting deeply-recursive
+            // binary nodes
+            var stack = ArrayBuilder<BoundBinaryPattern>.GetInstance();
+            BoundBinaryPattern? currentBinary = node;
+
+            do
+            {
+                stack.Push(currentBinary);
+                currentBinary = currentBinary.Left as BoundBinaryPattern;
+            }
+            while (currentBinary is not null);
+
+            Debug.Assert(stack.Count > 0);
+            var leftChild = (BoundPattern)Visit(stack.Peek().Left);
+
+            do
+            {
+                currentBinary = stack.Pop();
+
+                TypeSymbol inputType = GetUpdatedSymbol(currentBinary, currentBinary.InputType);
+                TypeSymbol narrowedType = GetUpdatedSymbol(currentBinary, currentBinary.NarrowedType);
+
+                var right = (BoundPattern)Visit(currentBinary.Right);
+
+                currentBinary = currentBinary.Update(currentBinary.Disjunction, leftChild, right, inputType, narrowedType);
+
+                leftChild = currentBinary;
+            }
+            while (stack.Count > 0);
+
+            return currentBinary;
+        }
+
         public override BoundNode? VisitCompoundAssignmentOperator(BoundCompoundAssignmentOperator node)
         {
             ImmutableArray<MethodSymbol> originalUserDefinedOperatorsOpt = GetUpdatedArray(node, node.OriginalUserDefinedOperatorsOpt);

src/Compilers/CSharp/Test/EndToEnd/EndToEndTests.cs

@@ -892,11 +892,13 @@ public void ManyBinaryPatterns_01(string pattern, string expectedOutput)
         public void ManyBinaryPatterns_02()
         {
             const int numOfEnumMembers = 5_000;
-            const int capacity = 97953;
+            const int capacity = 97973;
 
             var builder = new StringBuilder(capacity);
 
             builder.Append("""
+#nullable enable
+
 class ErrorFacts
 {
     static bool Test(E code)
@@ -942,7 +944,7 @@ enum E
             var source = builder.ToString();
             RunInThread(() =>
             {
-                var comp = CreateCompilation(source, options: TestOptions.DebugDll.WithConcurrentBuild(false), parseOptions: TestOptions.RegularDefault.WithFeature("run-nullable-analysis", "never"));
+                var comp = CreateCompilation(source, options: TestOptions.DebugDll.WithConcurrentBuild(false));
 
                 var tree = comp.SyntaxTrees.Single();
                 var model = comp.GetSemanticModel(tree);
@@ -959,9 +961,9 @@ enum E
                 Assert.NotNull(ControlFlowGraph.Create((IMethodBodyOperation)operation));
 
                 model.GetDiagnostics().Verify(
-                    // (5,21): warning CS8524: The switch expression does not handle some values of its input type (it is not exhaustive) involving an unnamed enum value. For example, the pattern '(E)5000' is not covered.
+                    // (7,21): warning CS8524: The switch expression does not handle some values of its input type (it is not exhaustive) involving an unnamed enum value. For example, the pattern '(E)5000' is not covered.
                     //         return code switch
-                    Diagnostic(ErrorCode.WRN_SwitchExpressionNotExhaustiveWithUnnamedEnumValue, "switch").WithArguments("(E)" + numOfEnumMembers).WithLocation(5, 21)
+                    Diagnostic(ErrorCode.WRN_SwitchExpressionNotExhaustiveWithUnnamedEnumValue, "switch").WithArguments("(E)" + numOfEnumMembers).WithLocation(7, 21)
                     );
             });
         }