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src/Features/CSharp/Portable/SimplifyTypeNames/SimplifyTypeNamesCodeFixProvider.cs

@@ -43,6 +43,10 @@ protected override string GetTitle(string diagnosticId, string nodeText)
 
         protected override SyntaxNode AddSimplificationAnnotationTo(SyntaxNode expressionSyntax)
         {
+            // Add the DoNotAllowVarAnnotation annotation.  All the code fixer
+            // does is pass the tagged node to the simplifier.  And we do *not*
+            // ever want the simplifier to produce 'var' in the 'Simplify type
+            // names' fixer.  only the 'Use var' fixer should produce 'var'.
             var annotatedexpressionSyntax = expressionSyntax.WithAdditionalAnnotations(
                 Simplifier.Annotation, Formatter.Annotation, DoNotAllowVarAnnotation.Annotation);