Fix null reference warnings in merge.

src/Features/Core/Portable/ConvertIfToSwitch/AbstractConvertIfToSwitchCodeRefactoringProvider.cs

@@ -45,7 +45,13 @@ public sealed override async Task ComputeRefactoringsAsync(CodeRefactoringContex
 
             var operations = parentBlock.Operations;
             var index = operations.IndexOf(ifOperation);
-            var analyzer = CreateAnalyzer(document.GetLanguageService<ISyntaxFactsService>(), ifStatement.SyntaxTree.Options);
+            var syntaxFactsService = document.GetLanguageService<ISyntaxFactsService>();
+            if (syntaxFactsService == null)
+            {
+                return;
+            }
+
+            var analyzer = CreateAnalyzer(syntaxFactsService, ifStatement.SyntaxTree.Options);
             var (sections, target) = analyzer.AnalyzeIfStatementSequence(operations.AsSpan().Slice(index));
             if (sections.IsDefaultOrEmpty)
             {

src/Features/Core/Portable/UseSystemHashCode/UseSystemHashCodeCodeFixProvider.cs

@@ -44,6 +44,10 @@ public override Task RegisterCodeFixesAsync(CodeFixContext context)
         {
             var generator = SyntaxGenerator.GetGenerator(document);
             var declarationService = document.GetLanguageService<ISymbolDeclarationService>();
+            if (declarationService == null)
+            {
+                return;
+            }
 
             var semanticModel = await document.RequireSemanticModelAsync(cancellationToken).ConfigureAwait(false);
             if (!Analyzer.TryGetAnalyzer(semanticModel.Compilation, out var analyzer))