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Author: CyrusNajmabadi

src/Analyzers/Core/Analyzers/RemoveUnusedMembers/AbstractRemoveUnusedMembersDiagnosticAnalyzer.cs

@@ -455,6 +455,11 @@ private void AnalyzeInvocationOperation(OperationAnalysisContext operationContex
             // A method invocation is considered as a read reference to the symbol
             // to ensure that we consider the method as "used".
             OnSymbolUsage(targetMethod, ValueUsageInfo.Read);
+
+            //// If the invoked method is a reduced extension method, also mark the original
+            //// method from which it was reduced as "used".
+            if (targetMethod.ReducedFrom != null)
+                OnSymbolUsage(targetMethod.ReducedFrom, ValueUsageInfo.Read);
         }
 
         private void AnalyzeNameOfOperation(OperationAnalysisContext operationContext)