Check ITypeHandler.Parse actually gets chance to parse values

Dapper NET40/SqlMapper.cs

@@ -1741,11 +1741,21 @@ private static CacheInfo GetCacheInfo(Identity identity, object exampleParameter
             if (!(typeMap.ContainsKey(type) || type.IsEnum || type.FullName == LinqBinary ||
                 (type.IsValueType && (underlyingType = Nullable.GetUnderlyingType(type)) != null && underlyingType.IsEnum)))
             {
+                ITypeHandler handler;
+                if (typeHandlers.TryGetValue(type, out handler))
+                {
+                    return GetHandlerDeserializer(handler, type, startBound);
+                }
                 return GetTypeDeserializer(type, reader, startBound, length, returnNullIfFirstMissing);
             }
             return GetStructDeserializer(type, underlyingType ?? type, startBound);
 
         }
+        static Func<IDataReader, object> GetHandlerDeserializer(ITypeHandler handler, Type type, int startBound)
+        {
+            return (IDataReader reader) =>
+                handler.Parse(type, reader.GetValue(startBound));
+        }
 
 #if !CSHARP30
         private sealed partial class DapperTable
@@ -3145,9 +3155,10 @@ public static void SetTypeMap(Type type, ITypeMap map)
                         {
                             Type dataType = reader.GetFieldType(index);
                             TypeCode dataTypeCode = Type.GetTypeCode(dataType), unboxTypeCode = Type.GetTypeCode(unboxType);
-                            if (dataType == unboxType || dataTypeCode == unboxTypeCode || dataTypeCode == Type.GetTypeCode(nullUnderlyingType))
+                            bool hasTypeHandler;
+                            if ((hasTypeHandler = typeHandlers.ContainsKey(unboxType)) || dataType == unboxType || dataTypeCode == unboxTypeCode || dataTypeCode == Type.GetTypeCode(nullUnderlyingType))
                             {
-                                if (typeHandlers.ContainsKey(unboxType))
+                                if (hasTypeHandler)
                                 {
 #pragma warning disable 618
                                     il.EmitCall(OpCodes.Call, typeof(TypeHandlerCache<>).MakeGenericType(unboxType).GetMethod("Parse"), null); // stack is now [target][target][typed-value]

Tests/Tests.cs

@@ -3098,6 +3098,54 @@ class PracticeRebateOrders
             public string TaxInvoiceNumber { get { return fTaxInvoiceNumber; } set { fTaxInvoiceNumber = value; } }
         }
 
+        public class RatingValueHandler : Dapper.SqlMapper.TypeHandler<RatingValue>
+        {
+            private RatingValueHandler() { }
+            public static readonly RatingValueHandler Default = new RatingValueHandler();
+            public override RatingValue Parse(object value)
+            {
+                if (value is Int32)
+                    return new RatingValue() { Value = (Int32)value };
+
+                throw new FormatException("Invalid conversion to RatingValue");
+            }
+
+            public override void SetValue(System.Data.IDbDataParameter parameter, RatingValue value)
+            {
+                // ... null, range checks etc ...
+                parameter.DbType = System.Data.DbType.Int32;
+                parameter.Value = value.Value;
+            }
+        }
+        public class RatingValue
+        {
+            public Int32 Value { get; set; }
+            // ... some other properties etc ...
+        }
+
+        public class MyResult
+        {
+            public String CategoryName { get; set; }
+            public RatingValue CategoryRating { get; set; }
+        }
+
+        public void SO24740733_TestCustomValueHandler()
+        {
+            Dapper.SqlMapper.AddTypeHandler(RatingValueHandler.Default);
+            var foo = connection.Query<MyResult>("SELECT 'Foo' AS CategoryName, 200 AS CategoryRating").Single();
+
+            foo.CategoryName.IsEqualTo("Foo");
+            foo.CategoryRating.Value.IsEqualTo(200);
+        }
+
+        public void SO24740733_TestCustomValueSingleColumn()
+        {
+            Dapper.SqlMapper.AddTypeHandler(RatingValueHandler.Default);
+            var foo = connection.Query<RatingValue>("SELECT 200 AS CategoryRating").Single();
+
+            foo.Value.IsEqualTo(200);
+        }
+
 #if POSTGRESQL
 
         class Cat