test: polish flat creation benchmark helper

Agent-Logs-Url: https://github.com/dadhi/FastExpressionCompiler/sessions/ed01d5a9-8337-4a93-a276-4c52a481fc65

Co-authored-by: dadhi <39516+dadhi@users.noreply.github.com>

Author: Copilot

test/FastExpressionCompiler.Benchmarks/LightExprVsFlatExpr_Create_ComplexExpr.cs

@@ -7,6 +7,7 @@ namespace FastExpressionCompiler.Benchmarks
     [MemoryDiagnoser, RankColumn, Orderer(BenchmarkDotNet.Order.SummaryOrderPolicy.FastestToSlowest)]
     public class LightExprVsFlatExpr_Create_ComplexExpr
     {
+        // Keep the created values reachable so the construction work is not elided.
         private FastExpressionCompiler.LightExpression.Expression<System.Func<object[], object>> _lightExpr;
         private ExprTree _flatExpr;
 

test/FastExpressionCompiler.LightExpression.UnitTests/LightExpressionTests.cs

@@ -236,10 +236,10 @@ public static Expression<Func<object[], object>> CreateComplexLightExpression_wi
             return expr;
         }
 
-        public static ExprTree CreateComplexFlatExpression(string p = null)
+        public static ExprTree CreateComplexFlatExpression(string parameterName = null)
         {
             var fe = default(ExprTree);
-            var stateParamExpr = fe.ParameterOf<object[]>(p);
+            var stateParamExpr = fe.ParameterOf<object[]>(parameterName);
             var body = fe.MemberInit(
                 fe.New(_ctorOfA,
                     fe.New(_ctorOfB),