Minimize changes

Author: bahusoid

src/NHibernate/Hql/Ast/ANTLR/Tree/CaseNode.cs

@@ -29,38 +29,17 @@ public override IType  DataType
 				if (ExpectedType != null)
 					return ExpectedType;
 
-				if (base.DataType != null)
-					return base.DataType;
-
-				var dataType = GetTypeFromResultNodes();
-
-				foreach (var node in GetResultNodes().OfType<ISelectExpression>())
+				foreach (var node in GetResultNodes())
 				{
-					if (node.DataType == null && node is IExpectedTypeAwareNode typeAwareNode)
-					{
-						typeAwareNode.ExpectedType = dataType;
-					}
+					if (node is ISelectExpression select && !(node is ParameterNode))
+						return select.DataType;
 				}
 
-				base.DataType = dataType;
-				return dataType;
+				throw new HibernateException("Unable to determine data type of CASE statement.");
 			}
 			set { base.DataType = value; }
 		}
 
-		private IType GetTypeFromResultNodes()
-		{
-			foreach (var node in GetResultNodes())
-			{
-				if (node is ISelectExpression select && select.DataType != null)
-				{
-					return select.DataType;
-				}
-			}
-
-			throw new HibernateException("Unable to determine data type of CASE statement.");
-		}
-
 		public IEnumerable<IASTNode> GetResultNodes()
 		{
 			for (int i = 0; i < ChildCount; i++)

src/NHibernate/Linq/Functions/StringGenerator.cs

@@ -217,8 +217,7 @@ public override HqlTreeNode BuildHql(MethodInfo method, Expression targetObject,
 		{
 			var expression = visitor.Visit(targetObject).AsExpression();
 			var index = treeBuilder.Add(visitor.Visit(arguments[0]).AsExpression(), treeBuilder.Constant(1));
-
-			return treeBuilder.TransparentCast(treeBuilder.MethodCall("substring", expression, index, treeBuilder.Constant(1)), typeof(char));
+			return treeBuilder.MethodCall("substring", expression, index, treeBuilder.Constant(1));
 		}
 	}
 

src/NHibernate/Linq/Visitors/ParameterTypeLocator.cs

@@ -93,8 +93,8 @@ internal static void SetParameterTypes(
 					continue;
 				}
 
-				namedParameter.Type = GetParameterType(sessionFactory, constantExpressions, visitor, namedParameter, out var isGuessedType);
-				namedParameter.IsGuessedType = isGuessedType;
+				namedParameter.Type = GetParameterType(sessionFactory, constantExpressions, visitor, namedParameter, out var tryProcessInHql);
+				namedParameter.IsGuessedType = tryProcessInHql;
 			}
 		}
 
@@ -147,9 +147,9 @@ private static IType GetParameterType(
 			HashSet<ConstantExpression> constantExpressions,
 			ConstantTypeLocatorVisitor visitor,
 			NamedParameter namedParameter,
-			out bool isGuessedType)
+			out bool tryProcessInHql)
 		{
-			isGuessedType = false;
+			tryProcessInHql = false;
 			// All constant expressions have the same type/value
 			var constantExpression = constantExpressions.First();
 			var constantType = constantExpression.Type.UnwrapIfNullable();
@@ -161,8 +161,7 @@ private static IType GetParameterType(
 
 			// Leave hql logic to determine the type except when the value is a char. Hql logic detects a char as a string, which causes an exception
 			// when trying to set a string db parameter with a char value.
-			isGuessedType = !(constantExpression.Value is char);
-
+			tryProcessInHql = !(constantExpression.Value is char);
 			// No related MemberExpressions was found, guess the type by value or its type when null.
 			// When a numeric parameter is compared to different columns with different types (e.g. Where(o => o.Single >= singleParam || o.Double <= singleParam))
 			// do not change the parameter type, but instead cast the parameter when comparing with different column types.