Fix and tests for http://stackoverflow.com/q/23696254/23354

Dapper NET40/SqlMapper.cs

@@ -1152,7 +1152,12 @@ private static IEnumerable<T> QueryImpl<T>(this IDbConnection cnn, CommandDefini
 
                 while (reader.Read())
                 {
-                    yield return (T)func(reader);
+                    object val = func(reader);
+                    if (val == null || val is T) {
+                        yield return (T)val;
+                    } else {
+                        yield return (T)Convert.ChangeType(val, typeof(T));
+                    }
                 }
                 // happy path; close the reader cleanly - no
                 // need for "Cancel" etc

Tests/Tests.cs

@@ -2671,7 +2671,7 @@ public void TestParameterInclusionNotSensitiveToCurrentCulture()
         public void LiteralReplacement()
         {
             connection.Execute("create table #literal1 (id int not null, foo int not null)");
-            connection.Execute("insert #literal1 (id,foo) values ({=id}, @foo)", new { id = 123, foo = 456});
+            connection.Execute("insert #literal1 (id,foo) values ({=id}, @foo)", new { id = 123, foo = 456 });
             var rows = new[] { new { id = 1, foo = 2 }, new { id = 3, foo = 4 } };
             connection.Execute("insert #literal1 (id,foo) values ({=id}, @foo)", rows);
             var count = connection.Query<int>("select count(1) from #literal1 where id={=foo}", new { foo = 123 }).Single();
@@ -2799,6 +2799,21 @@ public void DbString()
             b.IsEqualTo(6);
         }
 
+        class HasInt32
+        {
+            public int Value { get; set; }
+        }
+        // http://stackoverflow.com/q/23696254/23354
+        public void DownwardIntegerConversion()
+        {
+            const string sql = "select cast(42 as bigint) as Value";
+            int i = connection.Query<HasInt32>(sql).Single().Value;
+            Assert.IsEqualTo(42, i);
+
+            i = connection.Query<int>(sql).Single();
+            Assert.IsEqualTo(42, i);
+        }
+
         class HasDoubleDecimal
         {
             public double A { get; set; }