Add test for erroneous string literal

src/EditorFeatures/CSharpTest/Structure/StringLiteralExpressionStructureTests.cs

@@ -11,10 +11,11 @@ namespace Microsoft.CodeAnalysis.Editor.CSharp.UnitTests.Structure
 {
     public class StringLiteralExpressionStructureTests : AbstractCSharpSyntaxNodeStructureTests<LiteralExpressionSyntax>
     {
-        internal override AbstractSyntaxStructureProvider CreateProvider() => new StringLiteralExpressoinStructureProvider();
+        internal override AbstractSyntaxStructureProvider CreateProvider()
+            => new StringLiteralExpressoinStructureProvider();
 
         [Fact, Trait(Traits.Feature, Traits.Features.Outlining)]
-        public async Task TestVerbatimString()
+        public async Task TestMultiLineStringLiteral()
         {
             await VerifyBlockSpansAsync(
 @"
@@ -32,5 +33,19 @@ class
 }",
                 Region("textspan", "hint", CSharpStructureHelpers.Ellipsis, autoCollapse: true));
         }
+
+        [Fact, Trait(Traits.Feature, Traits.Features.Outlining)]
+        public async Task TestMissingOnIncompleteStringLiteral()
+        {
+            await VerifyNoBlockSpansAsync(
+@"
+class C
+{
+    void M()
+    {
+        var v = $$"";
+    }
+}");
+        }
     }
 }

src/Features/CSharp/Portable/Structure/CSharpBlockStructureProvider.cs

@@ -41,6 +41,7 @@ internal class CSharpBlockStructureProvider : AbstractBlockStructureProvider
             builder.Add<SimpleLambdaExpressionSyntax, SimpleLambdaExpressionStructureProvider>();
             builder.Add<StructDeclarationSyntax, TypeDeclarationStructureProvider, MetadataAsSource.MetadataTypeDeclarationStructureProvider>();
             builder.Add<SwitchStatementSyntax, SwitchStatementStructureProvider>();
+            builder.Add<LiteralExpressionSyntax, StringLiteralExpressoinStructureProvider>();
 
             return builder.ToImmutable();
         }

src/Features/CSharp/Portable/Structure/Providers/StringLiteralExpressoinStructureProvider.cs

@@ -12,7 +12,8 @@ internal sealed class StringLiteralExpressoinStructureProvider : AbstractSyntaxN
     {
         protected override void CollectBlockSpans(LiteralExpressionSyntax node, ArrayBuilder<BlockSpan> spans, OptionSet options, CancellationToken cancellationToken)
         {
-            if (node.IsKind(SyntaxKind.StringLiteralExpression))
+            if (node.IsKind(SyntaxKind.StringLiteralExpression) &&
+                !node.ContainsDiagnostics)
             {
                 spans.Add(new BlockSpan(
                     isCollapsible: true,