Merge pull request #9732 from jmarolf/check-if-syntaxtree-is-supported

Check if syntax tree is present

src/EditorFeatures/Test2/EditorServicesTest2.vbproj

@@ -167,6 +167,7 @@
     <Compile Include="Diagnostics\UseAutoProperty\UseAutoPropertyTests.vb" />
     <Compile Include="Expansion\LambdaParameterExpansionTests.vb" />
     <Compile Include="GoToImplementation\GoToImplementationTests.vb" />
+    <Compile Include="IntelliSense\CompletionServiceTests.vb" />
     <Compile Include="InteractivePaste\InteractivePasteCommandHandlerTests.vb" />
     <Compile Include="IntelliSense\CompletionRulesTests.vb" />
     <Compile Include="LanguageServices\SyntaxFactsServiceTests.vb" />

src/EditorFeatures/Test2/IntelliSense/CompletionServiceTests.vb

+' Copyright (c) Microsoft.  All Rights Reserved.  Licensed under the Apache License, Version 2.0.  See License.txt in the project root for license information.
+
+Imports System.Globalization
+Imports System.Threading
+Imports System.Threading.Tasks
+Imports Microsoft.CodeAnalysis.Completion
+Imports Microsoft.CodeAnalysis.CSharp.Completion
+Imports Microsoft.CodeAnalysis.CSharp.Completion.Providers
+Imports Microsoft.CodeAnalysis.Editor.UnitTests.Workspaces
+Imports Microsoft.CodeAnalysis.Options
+Imports Microsoft.CodeAnalysis.Text
+Imports Moq
+
+Namespace Microsoft.CodeAnalysis.Editor.UnitTests.IntelliSense
+    Public Class CompletionServiceTests
+        <Fact>
+        Public Async Function TestComplemtionDoesNotCrashWhenSyntaxTreeNotPresent() As Task
+            Dim workspaceDefinition =
+            <Workspace>
+                <Project Language="NoCompilation" AssemblyName="TestAssembly" CommonReferencesPortable="true">
+                    <Document>
+                        var x = {}; // e.g., TypeScript code or anything else that doesn't support compilations
+                    </Document>
+                </Project>
+            </Workspace>
+            Using workspace = Await TestWorkspace.CreateAsync(workspaceDefinition)
+                Dim document = workspace.CurrentSolution.Projects.First.Documents.First
+                Dim mockCompletionService = New Mock(Of AbstractCompletionService)
+                mockCompletionService.Setup(Function(service) service.GetDefaultCompletionProviders()).Returns({New TestCompletionProvider()})
+
+                Dim list = Await mockCompletionService.Object.GetCompletionListAsync(
+                    document:=document,
+                    position:=0,
+                    triggerInfo:=CompletionTriggerInfo.CreateInvokeCompletionTriggerInfo(),
+                    options:=Nothing,
+                    providers:=Nothing,
+                    cancellationToken:=Nothing)
+                Assert.NotNull(list)
+                Assert.NotEmpty(list.Items)
+                Assert.True(list.Items.Length = 1, "Completion list contained more than one item")
+                Assert.Equal("Completion Item From Test Completion Provider", list.Items.First.DisplayText)
+            End Using
+        End Function
+
+        Private Class TestCompletionProvider
+            Inherits CompletionListProvider
+
+            Public Overrides Function IsTriggerCharacter(text As SourceText, characterPosition As Int32, options As OptionSet) As [Boolean]
+                Return True
+            End Function
+
+            Public Overrides Function ProduceCompletionListAsync(context As CompletionListContext) As Task
+                context.AddItem(New CompletionItem(Me, "Completion Item From Test Completion Provider", filterSpan:=New TextSpan(), descriptionFactory:=Nothing, glyph:=Nothing))
+                Return Task.CompletedTask
+            End Function
+        End Class
+    End Class
+End Namespace
\ No newline at end of file

src/Features/Core/Portable/Completion/AbstractCompletionService.cs

@@ -278,17 +278,24 @@ private static CompletionItem Disambiguate(CompletionItem item, CompletionItem e
             CancellationToken cancellationToken)
         {
             var context = new CompletionListContext(document, position, triggerInfo, options, cancellationToken);
-            var root = await document.GetSyntaxRootAsync(cancellationToken).ConfigureAwait(false);
-            if (!root.FullSpan.IntersectsWith(position))
+            if (document.SupportsSyntaxTree)
             {
-                try
+                var root = await document.GetSyntaxRootAsync(cancellationToken).ConfigureAwait(false);
+                if (!root.FullSpan.IntersectsWith(position))
                 {
-                    // Trying to track down source of https://github.com/dotnet/roslyn/issues/9325
-                    var sourceText = await document.GetTextAsync(cancellationToken).ConfigureAwait(false);
-                    ReportException(position, root, sourceText);
+                    try
+                    {
+                        // Trying to track down source of https://github.com/dotnet/roslyn/issues/9325
+                        var sourceText = await document.GetTextAsync(cancellationToken).ConfigureAwait(false);
+                        ReportException(position, root, sourceText);
+                    }
+                    catch (Exception e) when (FatalError.ReportWithoutCrash(e))
+                    {
+                    }
                 }
-                catch (Exception e) when (FatalError.ReportWithoutCrash(e))
+                else
                 {
+                    await provider.ProduceCompletionListAsync(context).ConfigureAwait(false);
                 }
             }
             else