From 547350002a1e5d9d705602bbba0158a72996bad9 Mon Sep 17 00:00:00 2001
From: Brennan <brecon@microsoft.com>
Date: Mon, 27 Jan 2020 18:10:19 -0800
Subject: [PATCH] Fix nullref in ComponentsAnalyzer (#18608)

---
 Directory.Build.props                                       | 3 +++
 src/Components/Analyzers/src/InternalUsageAnalyzer.cs       | 4 ++--
 .../UsesRendererTypesInDeclarations.cs                      | 6 +++++-
 3 files changed, 10 insertions(+), 3 deletions(-)

diff --git a/Directory.Build.props b/Directory.Build.props
index 6cbe46561b..b68fd8cb66 100644
--- a/Directory.Build.props
+++ b/Directory.Build.props
@@ -30,6 +30,9 @@
     -->
     <IsStableBuild>false</IsStableBuild>
     <IsStableBuild Condition=" '$(DotNetFinalVersionKind)' == 'release' ">true</IsStableBuild>
+
+    <!-- Workaround issue with ComponentsAnalyzer throwing for interfaces -->
+    <DisableImplicitComponentsAnalyzers>true</DisableImplicitComponentsAnalyzers>
   </PropertyGroup>
 
   <Import Project="eng\FlakyTests.BeforeArcade.props" />
diff --git a/src/Components/Analyzers/src/InternalUsageAnalyzer.cs b/src/Components/Analyzers/src/InternalUsageAnalyzer.cs
index 495e4c90fa..af77a42ecc 100644
--- a/src/Components/Analyzers/src/InternalUsageAnalyzer.cs
+++ b/src/Components/Analyzers/src/InternalUsageAnalyzer.cs
@@ -126,7 +126,7 @@ namespace Microsoft.Extensions.Internal
         // Similar logic here to VisitDeclarationSymbol, keep these in sync.
         private void VisitOperationSymbol(OperationAnalysisContext context, ISymbol symbol)
         {
-            if (symbol.ContainingAssembly == context.Compilation.Assembly)
+            if (symbol == null || symbol.ContainingAssembly == context.Compilation.Assembly)
             {
                 // The type is being referenced within the same assembly. This is valid use of an "internal" type
                 return;
@@ -155,7 +155,7 @@ namespace Microsoft.Extensions.Internal
         // Similar logic here to VisitOperationSymbol, keep these in sync.
         private void VisitDeclarationSymbol(SymbolAnalysisContext context, ISymbol symbol, ISymbol symbolForDiagnostic)
         {
-            if (symbol.ContainingAssembly == context.Compilation.Assembly)
+            if (symbol == null || symbol.ContainingAssembly == context.Compilation.Assembly)
             {
                 // This is part of the compilation, avoid this analyzer when building from source.
                 return;
diff --git a/src/Components/Analyzers/test/TestFiles/ComponentInternalUsageDiagnosticsAnalyzerTest/UsesRendererTypesInDeclarations.cs b/src/Components/Analyzers/test/TestFiles/ComponentInternalUsageDiagnosticsAnalyzerTest/UsesRendererTypesInDeclarations.cs
index e2877b0df5..0a0bd11b7b 100644
--- a/src/Components/Analyzers/test/TestFiles/ComponentInternalUsageDiagnosticsAnalyzerTest/UsesRendererTypesInDeclarations.cs
+++ b/src/Components/Analyzers/test/TestFiles/ComponentInternalUsageDiagnosticsAnalyzerTest/UsesRendererTypesInDeclarations.cs
@@ -22,11 +22,15 @@ namespace Microsoft.AspNetCore.Components.Analyzers.Tests.TestFiles.ComponentInt
             throw new NotImplementedException();
         }
 
-        /*MMParameter*/protected override Task UpdateDisplayAsync(in RenderBatch renderBatch) 
+        /*MMParameter*/protected override Task UpdateDisplayAsync(in RenderBatch renderBatch)
         {
             throw new NotImplementedException();
         }
 
         /*MMReturnType*/private Renderer GetRenderer() => _field;
+
+        public interface ITestInterface
+        {
+        }
     }
 }