VS crashes if xml is pasted in C# editor

[vladima]

Version Used:

Steps to Reproduce:

1. create new C# console app
2. paste text below as a body of Main

      <summary>Copies a range of elements from an <see cref="T:System.Array" /> starting at the first element and pastes them into another <see cref="T:System.Array" /> starting at the first element. The length is specified as a 32-bit integer.</summary>
      <param name="sourceArray">The <see cref="T:System.Array" /> that contains the data to copy.</param>
      <param name="destinationArray">The <see cref="T:System.Array" /> that receives the data.</param>
      <param name="length">A 32-bit integer that represents the number of elements to copy.</param>
      <exception cref="T:System.ArgumentNullException">
        <paramref name="sourceArray" /> is null.-or-<paramref name="destinationArray" /> is null.</exception>
      <exception cref="T:System.RankException">
        <paramref name="sourceArray" /> and <paramref name="destinationArray" /> have different ranks.</exception>
      <exception cref="T:System.ArrayTypeMismatchException">
        <paramref name="sourceArray" /> and <paramref name="destinationArray" /> are of incompatible types.</exception>
      <exception cref="T:System.InvalidCastException">At least one element in <paramref name="sourceArray" /> cannot be cast to the type of <paramref name="destinationArray" />.</exception>
      <exception cref="T:System.ArgumentOutOfRangeException">
        <paramref name="length" /> is less than zero.</exception>
      <exception cref="T:System.ArgumentException">
        <paramref name="length" /> is greater than the number of elements in <paramref name="sourceArray" />.-or-<paramref name="length" /> is greater than the number of elements in <paramref name="destinationArray" />.</exception>

Expected Behavior:
Sea of red in the editor.

Actual Behavior:
VS crashes:

Application: devenv.exe
Framework Version: v4.0.30319
Description: The application requested process termination through System.Environment.FailFast(string message).
Message: System.NullReferenceException: Object reference not set to an instance of an object.
   at Microsoft.CodeAnalysis.CSharp.Binder.BindDeclarationPattern(DeclarationPatternSyntax node, BoundExpression operand, TypeSymbol operandType, Boolean hasErrors, DiagnosticBag diagnostics)
   at Microsoft.CodeAnalysis.CSharp.Binder.BindPattern(PatternSyntax node, BoundExpression operand, TypeSymbol operandType, Boolean hasErrors, DiagnosticBag diagnostics, Boolean wasSwitchCase)
   at Microsoft.CodeAnalysis.CSharp.Binder.BindIsPatternExpression(IsPatternExpressionSyntax node, DiagnosticBag diagnostics)
   at Microsoft.CodeAnalysis.CSharp.Binder.BindExpressionInternal(ExpressionSyntax node, DiagnosticBag diagnostics, Boolean invoked, Boolean indexed)
   at Microsoft.CodeAnalysis.CSharp.Binder.BindExpression(ExpressionSyntax node, DiagnosticBag diagnostics, Boolean invoked, Boolean indexed)
   at Microsoft.CodeAnalysis.CSharp.Binder.BindNamespaceOrTypeOrExpression(ExpressionSyntax node, DiagnosticBag diagnostics)
   at Microsoft.CodeAnalysis.CSharp.CSharpSemanticModel.Bind(Binder binder, CSharpSyntaxNode node, DiagnosticBag diagnostics)
   at Microsoft.CodeAnalysis.CSharp.MethodBodySemanticModel.Bind(Binder binder, CSharpSyntaxNode node, DiagnosticBag diagnostics)
   at Microsoft.CodeAnalysis.CSharp.MemberSemanticModel.GetBoundNodes(CSharpSyntaxNode node)
   at Microsoft.CodeAnalysis.CSharp.MemberSemanticModel.GetLowerBoundNode(CSharpSyntaxNode node)
   at Microsoft.CodeAnalysis.CSharp.MemberSemanticModel.GetBoundNodes(CSharpSyntaxNode node, CSharpSyntaxNode& bindableNode, BoundNode& lowestBoundNode, BoundNode& highestBoundNode, BoundNode& boundParent)
   at Microsoft.CodeAnalysis.CSharp.MemberSemanticModel.GetSymbolInfoWorker(CSharpSyntaxNode node, SymbolInfoOptions options, CancellationToken cancellationToken)
   at Microsoft.CodeAnalysis.CSharp.CSharpSemanticModel.GetSymbolInfo(ExpressionSyntax expression, CancellationToken cancellationToken)
   at Microsoft.CodeAnalysis.CSharp.CSharpExtensions.GetSymbolInfo(SemanticModel semanticModel, ExpressionSyntax expression, CancellationToken cancellationToken)
   at Microsoft.CodeAnalysis.CSharp.Classification.Classifiers.NameSyntaxClassifier.ClassifyTypeSyntax(NameSyntax name, SemanticModel semanticModel, CancellationToken cancellationToken)
   at Microsoft.CodeAnalysis.CSharp.Classification.Classifiers.NameSyntaxClassifier.ClassifyNode(SyntaxNode syntax, SemanticModel semanticModel, CancellationToken cancellationToken)
   at Microsoft.CodeAnalysis.Classification.AbstractClassificationService.Worker.ClassifyNode(SyntaxNode syntax)
   at Microsoft.CodeAnalysis.Classification.AbstractClassificationService.Worker.ProcessNodes()
   at Microsoft.CodeAnalysis.Classification.AbstractClassificationService.Worker.Classify(Workspace workspace, SemanticModel semanticModel, TextSpan textSpan, List`1 list, Func`2 getNodeClassifiers, Func`2 getTokenClassifiers, CancellationToken cancellationToken)
   at Microsoft.CodeAnalysis.Classification.AbstractClassificationService.<AddSemanticClassificationsAsync>d__5.MoveNext()
Stack:
   at System.Environment.FailFast(System.String, System.Exception)
   at Microsoft.CodeAnalysis.FailFast.OnFatalException(System.Exception)
   at Microsoft.CodeAnalysis.ErrorReporting.FatalError.Report(System.Exception, System.Action`1<System.Exception>)
   at Microsoft.CodeAnalysis.ErrorReporting.FatalError.ReportUnlessCanceled(System.Exception)
   at Microsoft.CodeAnalysis.Classification.AbstractClassificationService+<AddSemanticClassificationsAsync>d__5.MoveNext()
   at Microsoft.CodeAnalysis.CSharp.Binder.BindDeclarationPattern(Microsoft.CodeAnalysis.CSharp.Syntax.DeclarationPatternSyntax, Microsoft.CodeAnalysis.CSharp.BoundExpression, Microsoft.CodeAnalysis.CSharp.Symbols.TypeSymbol, Boolean, Microsoft.CodeAnalysis.DiagnosticBag)
   at Microsoft.CodeAnalysis.CSharp.Binder.BindPattern(Microsoft.CodeAnalysis.CSharp.Syntax.PatternSyntax, Microsoft.CodeAnalysis.CSharp.BoundExpression, Microsoft.CodeAnalysis.CSharp.Symbols.TypeSymbol, Boolean, Microsoft.CodeAnalysis.DiagnosticBag, Boolean)
   at Microsoft.CodeAnalysis.CSharp.Binder.BindIsPatternExpression(Microsoft.CodeAnalysis.CSharp.Syntax.IsPatternExpressionSyntax, Microsoft.CodeAnalysis.DiagnosticBag)
   at Microsoft.CodeAnalysis.CSharp.Binder.BindExpressionInternal(Microsoft.CodeAnalysis.CSharp.Syntax.ExpressionSyntax, Microsoft.CodeAnalysis.DiagnosticBag, Boolean, Boolean)
   at Microsoft.CodeAnalysis.CSharp.Binder.BindExpression(Microsoft.CodeAnalysis.CSharp.Syntax.ExpressionSyntax, Microsoft.CodeAnalysis.DiagnosticBag, Boolean, Boolean)
   at Microsoft.CodeAnalysis.CSharp.Binder.BindNamespaceOrTypeOrExpression(Microsoft.CodeAnalysis.CSharp.Syntax.ExpressionSyntax, Microsoft.CodeAnalysis.DiagnosticBag)
   at Microsoft.CodeAnalysis.CSharp.CSharpSemanticModel.Bind(Microsoft.CodeAnalysis.CSharp.Binder, Microsoft.CodeAnalysis.CSharp.CSharpSyntaxNode, Microsoft.CodeAnalysis.DiagnosticBag)
   at Microsoft.CodeAnalysis.CSharp.MethodBodySemanticModel.Bind(Microsoft.CodeAnalysis.CSharp.Binder, Microsoft.CodeAnalysis.CSharp.CSharpSyntaxNode, Microsoft.CodeAnalysis.DiagnosticBag)
   at Microsoft.CodeAnalysis.CSharp.MemberSemanticModel.GetBoundNodes(Microsoft.CodeAnalysis.CSharp.CSharpSyntaxNode)
   at Microsoft.CodeAnalysis.CSharp.MemberSemanticModel.GetLowerBoundNode(Microsoft.CodeAnalysis.CSharp.CSharpSyntaxNode)
   at Microsoft.CodeAnalysis.CSharp.MemberSemanticModel.GetBoundNodes(Microsoft.CodeAnalysis.CSharp.CSharpSyntaxNode, Microsoft.CodeAnalysis.CSharp.CSharpSyntaxNode ByRef, Microsoft.CodeAnalysis.CSharp.BoundNode ByRef, Microsoft.CodeAnalysis.CSharp.BoundNode ByRef, Microsoft.CodeAnalysis.CSharp.BoundNode ByRef)
   at Microsoft.CodeAnalysis.CSharp.MemberSemanticModel.GetSymbolInfoWorker(Microsoft.CodeAnalysis.CSharp.CSharpSyntaxNode, SymbolInfoOptions, System.Threading.CancellationToken)
   at Microsoft.CodeAnalysis.CSharp.CSharpSemanticModel.GetSymbolInfo(Microsoft.CodeAnalysis.CSharp.Syntax.ExpressionSyntax, System.Threading.CancellationToken)
   at Microsoft.CodeAnalysis.CSharp.CSharpExtensions.GetSymbolInfo(Microsoft.CodeAnalysis.SemanticModel, Microsoft.CodeAnalysis.CSharp.Syntax.ExpressionSyntax, System.Threading.CancellationToken)
   at Microsoft.CodeAnalysis.CSharp.Classification.Classifiers.NameSyntaxClassifier.ClassifyTypeSyntax(Microsoft.CodeAnalysis.CSharp.Syntax.NameSyntax, Microsoft.CodeAnalysis.SemanticModel, System.Threading.CancellationToken)
   at Microsoft.CodeAnalysis.CSharp.Classification.Classifiers.NameSyntaxClassifier.ClassifyNode(Microsoft.CodeAnalysis.SyntaxNode, Microsoft.CodeAnalysis.SemanticModel, System.Threading.CancellationToken)
   at Microsoft.CodeAnalysis.Classification.AbstractClassificationService+Worker.ClassifyNode(Microsoft.CodeAnalysis.SyntaxNode)
   at Microsoft.CodeAnalysis.Classification.AbstractClassificationService+Worker.ProcessNodes()
   at Microsoft.CodeAnalysis.Classification.AbstractClassificationService+Worker.Classify(Microsoft.CodeAnalysis.Workspace, Microsoft.CodeAnalysis.SemanticModel, Microsoft.CodeAnalysis.Text.TextSpan, System.Collections.Generic.List`1<Microsoft.CodeAnalysis.Classification.ClassifiedSpan>, System.Func`2<Microsoft.CodeAnalysis.SyntaxNode,System.Collections.Generic.List`1<Microsoft.CodeAnalysis.Classification.Classifiers.ISyntaxClassifier>>, System.Func`2<Microsoft.CodeAnalysis.SyntaxToken,System.Collections.Generic.List`1<Microsoft.CodeAnalysis.Classification.Classifiers.ISyntaxClassifier>>, System.Threading.CancellationToken)
   at Microsoft.CodeAnalysis.Classification.AbstractClassificationService+<AddSemanticClassificationsAsync>d__5.MoveNext()
   at System.Runtime.CompilerServices.AsyncTaskMethodBuilder.Start[[Microsoft.CodeAnalysis.Classification.AbstractClassificationService+<AddSemanticClassificationsAsync>d__5, Microsoft.CodeAnalysis.Workspaces, Version=2.0.0.0, Culture=neutral, PublicKeyToken=31bf3856ad364e35]](<AddSemanticClassificationsAsync>d__5 ByRef)
   at Microsoft.CodeAnalysis.Classification.AbstractClassificationService.AddSemanticClassificationsAsync(Microsoft.CodeAnalysis.Document, Microsoft.CodeAnalysis.Text.TextSpan, System.Func`2<Microsoft.CodeAnalysis.SyntaxNode,System.Collections.Generic.List`1<Microsoft.CodeAnalysis.Classification.Classifiers.ISyntaxClassifier>>, System.Func`2<Microsoft.CodeAnalysis.SyntaxToken,System.Collections.Generic.List`1<Microsoft.CodeAnalysis.Classification.Classifiers.ISyntaxClassifier>>, System.Collections.Generic.List`1<Microsoft.CodeAnalysis.Classification.ClassifiedSpan>, System.Threading.CancellationToken)
   at Microsoft.CodeAnalysis.Editor.Implementation.Classification.AbstractEditorClassificationService.AddSemanticClassificationsAsync(Microsoft.CodeAnalysis.Document, Microsoft.CodeAnalysis.Text.TextSpan, System.Collections.Generic.List`1<Microsoft.CodeAnalysis.Classification.ClassifiedSpan>, System.Threading.CancellationToken)
   at Microsoft.CodeAnalysis.Editor.Implementation.Classification.SemanticClassificationUtilities+<ClassifySpansAsync>d__2.MoveNext()
   at System.Runtime.CompilerServices.AsyncTaskMethodBuilder.Start[[Microsoft.CodeAnalysis.Editor.Implementation.Classification.SemanticClassificationUtilities+<ClassifySpansAsync>d__2, Microsoft.CodeAnalysis.EditorFeatures, Version=2.0.0.0, Culture=neutral, PublicKeyToken=31bf3856ad364e35]](<ClassifySpansAsync>d__2 ByRef)
   at Microsoft.CodeAnalysis.Editor.Implementation.Classification.SemanticClassificationUtilities.ClassifySpansAsync(Microsoft.CodeAnalysis.Editor.Tagging.TaggerContext`1<Microsoft.VisualStudio.Text.Tagging.IClassificationTag>, Microsoft.CodeAnalysis.Editor.DocumentSnapshotSpan, Microsoft.CodeAnalysis.Editor.IEditorClassificationService, Microsoft.CodeAnalysis.Editor.Shared.Utilities.ClassificationTypeMap)
   at Microsoft.CodeAnalysis.Editor.Implementation.Classification.SemanticClassificationUtilities+<TryClassifyContainingMemberSpan>d__1.MoveNext()
   at System.Runtime.CompilerServices.AsyncTaskMethodBuilder`1[[System.Boolean, mscorlib, Version=4.0.0.0, Culture=neutral, PublicKeyToken=b77a5c561934e089]].Start[[Microsoft.CodeAnalysis.Editor.Implementation.Classification.SemanticClassificationUtilities+<TryClassifyContainingMemberSpan>d__1, Microsoft.CodeAnalysis.EditorFeatures, Version=2.0.0.0, Culture=neutral, PublicKeyToken=31bf3856ad364e35]](<TryClassifyContainingMemberSpan>d__1 ByRef)
   at Microsoft.CodeAnalysis.Editor.Implementation.Classification.SemanticClassificationUtilities.TryClassifyContainingMemberSpan(Microsoft.CodeAnalysis.Editor.Tagging.TaggerContext`1<Microsoft.VisualStudio.Text.Tagging.IClassificationTag>, Microsoft.CodeAnalysis.Editor.DocumentSnapshotSpan, Microsoft.CodeAnalysis.Editor.IEditorClassificationService, Microsoft.CodeAnalysis.Editor.Shared.Utilities.ClassificationTypeMap)
   at Microsoft.CodeAnalysis.Editor.Implementation.Classification.SemanticClassificationUtilities+<ProduceTagsAsync>d__0.MoveNext()
   at System.Runtime.CompilerServices.AsyncTaskMethodBuilder.Start[[Microsoft.CodeAnalysis.Editor.Implementation.Classification.SemanticClassificationUtilities+<ProduceTagsAsync>d__0, Microsoft.CodeAnalysis.EditorFeatures, Version=2.0.0.0, Culture=neutral, PublicKeyToken=31bf3856ad364e35]](<ProduceTagsAsync>d__0 ByRef)
   at Microsoft.CodeAnalysis.Editor.Implementation.Classification.SemanticClassificationUtilities.ProduceTagsAsync(Microsoft.CodeAnalysis.Editor.Tagging.TaggerContext`1<Microsoft.VisualStudio.Text.Tagging.IClassificationTag>, Microsoft.CodeAnalysis.Editor.DocumentSnapshotSpan, Microsoft.CodeAnalysis.Editor.IEditorClassificationService, Microsoft.CodeAnalysis.Editor.Shared.Utilities.ClassificationTypeMap)
   at Microsoft.CodeAnalysis.Editor.Implementation.Classification.SemanticClassificationViewTaggerProvider.ProduceTagsAsync(Microsoft.CodeAnalysis.Editor.Tagging.TaggerContext`1<Microsoft.VisualStudio.Text.Tagging.IClassificationTag>)
   at Microsoft.CodeAnalysis.Editor.Tagging.AbstractAsynchronousTaggerProvider`1+TagSource+<RecomputeTagsAsync>d__83[[System.__Canon, mscorlib, Version=4.0.0.0, Culture=neutral, PublicKeyToken=b77a5c561934e089]].MoveNext()
   at System.Runtime.CompilerServices.AsyncTaskMethodBuilder.Start[[Microsoft.CodeAnalysis.Editor.Tagging.AbstractAsynchronousTaggerProvider`1+TagSource+<RecomputeTagsAsync>d__83[[System.__Canon, mscorlib, Version=4.0.0.0, Culture=neutral, PublicKeyToken=b77a5c561934e089]], Microsoft.CodeAnalysis.EditorFeatures, Version=2.0.0.0, Culture=neutral, PublicKeyToken=31bf3856ad364e35]](<RecomputeTagsAsync>d__83<System.__Canon> ByRef)
   at Microsoft.CodeAnalysis.Editor.Tagging.AbstractAsynchronousTaggerProvider`1+TagSource[[System.__Canon, mscorlib, Version=4.0.0.0, Culture=neutral, PublicKeyToken=b77a5c561934e089]].RecomputeTagsAsync(System.Object, System.Nullable`1<Microsoft.VisualStudio.Text.SnapshotPoint>, System.Nullable`1<Microsoft.CodeAnalysis.Text.TextChangeRange>, System.Collections.Generic.List`1<Microsoft.CodeAnalysis.Editor.DocumentSnapshotSpan>, System.Collections.Immutable.ImmutableDictionary`2<Microsoft.VisualStudio.Text.ITextBuffer,Microsoft.CodeAnalysis.Editor.Shared.Tagging.TagSpanIntervalTree`1<System.__Canon>>, System.Threading.CancellationToken)
   at Microsoft.CodeAnalysis.Editor.Tagging.AbstractAsynchronousTaggerProvider`1+TagSource+<>c__DisplayClass74_0[[System.__Canon, mscorlib, Version=4.0.0.0, Culture=neutral, PublicKeyToken=b77a5c561934e089]].<RecomputeTagsForeground>b__0(System.Threading.CancellationToken)
   at Microsoft.CodeAnalysis.Editor.Shared.Threading.AsynchronousSerialWorkQueue+<>c__DisplayClass11_0.<EnqueueBackgroundTask>b__0(System.Threading.Tasks.Task)
   at System.Threading.Tasks.ContinuationResultTaskFromTask`1[[System.__Canon, mscorlib, Version=4.0.0.0, Culture=neutral, PublicKeyToken=b77a5c561934e089]].InnerInvoke()
   at System.Threading.Tasks.Task.Execute()
   at System.Threading.Tasks.Task.ExecutionContextCallback(System.Object)
   at System.Threading.ExecutionContext.RunInternal(System.Threading.ExecutionContext, System.Threading.ContextCallback, System.Object, Boolean)
   at System.Threading.ExecutionContext.Run(System.Threading.ExecutionContext, System.Threading.ContextCallback, System.Object, Boolean)
   at System.Threading.Tasks.Task.ExecuteWithThreadLocal(System.Threading.Tasks.Task ByRef)
   at System.Threading.Tasks.Task.ExecuteEntry(Boolean)
   at System.Threading.Tasks.Task.System.Threading.IThreadPoolWorkItem.ExecuteWorkItem()
   at System.Threading.ThreadPoolWorkQueue.Dispatch()
   at System.Threading._ThreadPoolWaitCallback.PerformWaitCallback()

[CyrusNajmabadi]

Tagging @gafter @jcouv as this relates to BindDeclarationPattern

[gafter]

Here is a narrowed-down test case:

        [Fact, WorkItem(16167, "https://github.com/dotnet/roslyn/issues/16167")]
        public void Bug16167Root()
        {
            var text = @"
using System;
using System.Collections.Generic;
using System.Linq;

class C
{
    public static void Main(string[] args)
    {
        void Local1(bool b = args is string[] z1) {}
        void Local2(bool b = M(out int z2)) {}
        void Local3((int, int) ii = ((int a1, int a2) = (1, 2)) {}
    }
    public static M(out int z) z = 1;
}
";
            var compilation = CreateCompilationWithMscorlib45(text);
            var tree = compilation.SyntaxTrees[0];
            var model = compilation.GetSemanticModel(tree);
            foreach (var node in tree.GetRoot().DescendantNodes())
            {
                var _ = model.GetSymbolInfo(node);
            }
        }

[jaredpar]

This was also hit by the following Watson issue

https://devdiv.visualstudio.com/DefaultCollection/DevDiv/_workitems?_a=edit&id=363720&triage=true