Merge pull request diesel-rs#1380 from diesel-rs/sg-mysql-datetime-type

Implement various "primitive" traits for `Datetime`

Author: sgrif

diesel/src/mysql/types/date_and_time.rs

@@ -42,7 +42,8 @@ macro_rules! mysql_time_impls {
 }
 
 mysql_time_impls!(Datetime);
-primitive_impls!(Datetime -> NaiveDateTime);
+queryable_impls!(Datetime -> NaiveDateTime);
+expression_impls!(Datetime -> NaiveDateTime);
 mysql_time_impls!(Timestamp);
 mysql_time_impls!(Time);
 mysql_time_impls!(Date);

diesel/src/mysql/types/mod.rs

@@ -97,3 +97,5 @@ impl QueryId for ::types::Numeric {
 /// [NaiveDateTime]: https://lifthrasiir.github.io/rust-chrono/chrono/naive/datetime/struct.NaiveDateTime.html
 #[derive(Debug, Clone, Copy, Default)]
 pub struct Datetime;
+
+primitive_impls!(Datetime);