Move number type checks to TypeExtensions and extract additional method to make code more readable

Author: hazzik

src/NHibernate/Linq/Visitors/ParameterTypeLocator.cs

@@ -141,6 +141,29 @@ private static IType GetCandidateType(
 			return candidateType;
 		}
 
+		private static IType GetCandidateType(
+			ISessionFactoryImplementor sessionFactory,
+			HashSet<ConstantExpression> constantExpressions,
+			ConstantTypeLocatorVisitor visitor,
+			System.Type constantType)
+		{
+			var candidateType = GetCandidateType(sessionFactory, constantExpressions, visitor);
+			    
+			if (candidateType == null)
+			{
+				return null;
+			}
+			
+			// When comparing an integral column with a real parameter, the parameter type must remain real type
+			// and the column needs to be casted in order to prevent invalid results (e.g. Where(o => o.Integer >= 2.2d)).
+			if (constantType.IsRealNumberType() && candidateType.ReturnedClass.IsIntegralNumberType())
+			{
+				return null;
+			}
+
+			return candidateType;
+		}
+
 		private static IType GetParameterType(
 			ISessionFactoryImplementor sessionFactory,
 			HashSet<ConstantExpression> constantExpressions,