Merge pull request #28483 from MaStr11/fix_InternalsVisibleToCompletionProvider_XamlProjects

Fix InternalsVisibleToCompletionProvider showing unsupported project types

src/EditorFeatures/Test2/IntelliSense/CSharpCompletionCommandHandlerTests_InternalsVisibleTo.vb

@@ -580,5 +580,23 @@ using System.Reflection;
                 Assert.True(state.CompletionItemsContainsAll({"ClassLibrary2"}))
             End Using
         End Function
+
+        <WpfFact, Trait(Traits.Feature, Traits.Features.Completion)>
+        Public Async Function CodeCompletionIgnoresUnsupportedProjectTypes() As Task
+            Using state = TestState.CreateTestStateFromWorkspace(
+                <Workspace>
+                    <Project Language="NoCompilation" AssemblyName="ClassLibrary1"/>
+                    <Project Language="C#" CommonReferences="true" AssemblyName="TestAssembly">
+                        <Document FilePath="C.cs">
+using System.Runtime.CompilerServices;
+using System.Reflection;
+[assembly: InternalsVisibleTo("$$
+                        </Document>
+                    </Project>
+                </Workspace>)
+                state.SendInvokeCompletionList()
+                Await state.AssertNoCompletionSession()
+            End Using
+        End Function
     End Class
 End Namespace

src/EditorFeatures/TestUtilities2/Intellisense/TestState.vb

@@ -62,8 +62,10 @@ Namespace Microsoft.CodeAnalysis.Editor.UnitTests.IntelliSense
 
             If extraCompletionProviders IsNot Nothing Then
                 Dim completionService = DirectCast(languageServices.GetService(Of CompletionService), CompletionServiceWithProviders)
+                If completionService IsNot Nothing Then
                     completionService.SetTestProviders(extraCompletionProviders.Select(Function(lz) lz.Value).ToList())
                 End If
+            End If
 
             Me.SessionTestState = GetExportedValue(Of IIntelliSenseTestState)()
 

src/Features/Core/Portable/Completion/Providers/AbstractInternalsVisibleToCompletionProvider.cs

@@ -130,6 +130,11 @@ private async Task AddAssemblyCompletionItemsAsync(CompletionContext context, Ca
                     continue;
                 }
 
+                if (IsProjectTypeUnsupported(project))
+                {
+                    continue;
+                }
+
                 if (allInternalsVisibleToAttributesOfProject.Contains(project.AssemblyName))
                 {
                     continue;
@@ -145,6 +150,9 @@ private async Task AddAssemblyCompletionItemsAsync(CompletionContext context, Ca
             }
         }
 
+        private static bool IsProjectTypeUnsupported(Project project)
+            => !project.SupportsCompilation;
+
         private async Task<IImmutableSet<string>> GetAllInternalsVisibleToAssemblyNamesOfProjectAsync(CompletionContext completionContext, CancellationToken cancellationToken)
         {
             // Looking up other InternalsVisibleTo attributes of this project. This is faster than compiling all projects of the solution and checking access via