Backslach in interpolated raw string literal

[ufcpp]

Version Used:

Version 17.2.0 Preview 1.0

Steps to Reproduce:

$"""
\
"""

An internal error reported when typing \.

Another steps to reproduce:

With Microsoft.CodeAnalysis.CSharp.Workspaces Version=4.2.0-1.final

using Microsoft.CodeAnalysis;
using Microsoft.CodeAnalysis.Classification;
using Microsoft.CodeAnalysis.Text;

using var ws = new AdhocWorkspace();
var proj = ws.AddProject("A", LanguageNames.CSharp);
var doc = proj.AddDocument("A.cs", """"
$"""
\
"""
"""");

var text = await doc.GetTextAsync();
var spans = await Classifier.GetClassifiedSpansAsync(doc, TextSpan.FromBounds(0, text.Length)); // IndexOutOfRangeException thrown

Expected Behavior:

No error.

Actual Behavior:

Feature 'Semantic classification' is currently unavailable due to an internal error.

Stack Trace:

Microsoft.CodeAnalysis.CSharp.EmbeddedLanguages.VirtualChars.CSharpVirtualCharService.TryAddSingleCharacterEscape(ArrayBuilder`1 result, String tokenText, Int32 offset, Int32 index)
Microsoft.CodeAnalysis.CSharp.EmbeddedLanguages.VirtualChars.CSharpVirtualCharService.TryConvertStringToVirtualChars(SyntaxToken token, String startDelimiter, String endDelimiter, Boolean escapeBraces)
Microsoft.CodeAnalysis.CSharp.EmbeddedLanguages.VirtualChars.CSharpVirtualCharService.TryConvertToVirtualCharsWorker(SyntaxToken token)
Microsoft.CodeAnalysis.EmbeddedLanguages.VirtualChars.AbstractVirtualCharService.TryConvertToVirtualChars(SyntaxToken token)
Microsoft.CodeAnalysis.EmbeddedLanguages.LanguageServices.FallbackSyntaxClassifier.AddClassifications(SyntaxToken token, SemanticModel semanticModel, ClassificationOptions options, ArrayBuilder`1 result, CancellationToken cancellationToken)
Microsoft.CodeAnalysis.Classification.Classifiers.EmbeddedLanguagesClassifier.AddClassifications(SyntaxToken token, SemanticModel semanticModel, ClassificationOptions options, ArrayBuilder`1 result, CancellationToken cancellationToken)
Microsoft.CodeAnalysis.Classification.AbstractSyntaxClassificationService.Worker.ClassifyToken(SyntaxToken syntax)
Microsoft.CodeAnalysis.Classification.AbstractSyntaxClassificationService.Worker.ProcessNodes()
Microsoft.CodeAnalysis.Classification.AbstractSyntaxClassificationService.Worker.Classify(SemanticModel semanticModel, TextSpan textSpan, ArrayBuilder`1 list, Func`2 getNodeClassifiers, Func`2 getTokenClassifiers, ClassificationOptions options, CancellationToken cancellationToken)
Microsoft.CodeAnalysis.Classification.AbstractSyntaxClassificationService.<AddSemanticClassificationsAsync>d__5.MoveNext()

[CyrusNajmabadi]

Hrmm. Not repro'ing this. Trying some more configurations.

[CyrusNajmabadi]

Got it. Working on fix now.