Avoid lambda compilation for constant and member access expressions in LINQ

Author: bahusoid

src/NHibernate/Linq/Visitors/NhPartialEvaluatingExpressionVisitor.cs

@@ -20,6 +20,7 @@
 using System.Linq.Expressions;
 using NHibernate.Collection;
 using NHibernate.Engine;
+using NHibernate.Impl;
 using NHibernate.Linq.Functions;
 using NHibernate.Util;
 using Remotion.Linq.Parsing;
@@ -143,14 +144,8 @@ private Expression EvaluateSubtree(Expression subtree)
 
 				return constantExpression;
 			}
-			else
-			{
-				Expression<Func<object>> lambdaWithoutParameters = Expression.Lambda<Func<object>>(Expression.Convert(subtree, typeof(object)));
-				var compiledLambda = lambdaWithoutParameters.Compile();
 
-				object value = compiledLambda();
-				return Expression.Constant(value, subtree.Type);
-			}
+			return Expression.Constant(ExpressionProcessor.FindValue(subtree), subtree.Type);
 		}
 
 		#region NH additions