Merge pull request #4193 from guissalustiano/multirange_functions

Extend range functions to support nullable and multirange

diesel/src/pg/expression/expression_methods.rs

@@ -2,8 +2,8 @@
 
 pub(in crate::pg) use self::private::{
     ArrayOrNullableArray, InetOrCidr, JsonIndex, JsonOrNullableJsonOrJsonbOrNullableJsonb,
-    JsonRemoveIndex, JsonbOrNullableJsonb, MultirangeOrRangeMaybeNullable, RangeHelper,
-    RangeOrNullableRange, TextOrNullableText,
+    JsonRemoveIndex, JsonbOrNullableJsonb, MultirangeOrNullableMultirange,
+    MultirangeOrRangeMaybeNullable, RangeHelper, RangeOrNullableRange, TextOrNullableText,
 };
 use super::date_and_time::{AtTimeZone, DateTimeLike};
 use super::operators::*;
@@ -3485,10 +3485,37 @@ pub(in crate::pg) mod private {
         message = "`{Self}` is neither `diesel::sql_types::Range<_>` nor `diesel::sql_types::Nullable<Range<_>>`",
         note = "try to provide an expression that produces one of the expected sql types"
     )]
-    pub trait RangeOrNullableRange {}
+    pub trait RangeOrNullableRange {
+        type Inner: SingleValue;
+    }
 
-    impl<ST> RangeOrNullableRange for Range<ST> {}
-    impl<ST> RangeOrNullableRange for Nullable<Range<ST>> {}
+    impl<ST: SingleValue> RangeOrNullableRange for Range<ST> {
+        type Inner = ST;
+    }
+    impl<ST: SingleValue> RangeOrNullableRange for Nullable<Range<ST>> {
+        type Inner = ST;
+    }
+
+    /// Marker trait used to implement `PgRangeExpressionMethods` on the appropriate
+    /// types. Once coherence takes associated types into account, we can remove
+    /// this trait.
+    #[diagnostic::on_unimplemented(
+        message = "`{Self}` is neither `diesel::sql_types::Range<_>` nor `diesel::sql_types::Nullable<Range<_>>`",
+        note = "try to provide an expression that produces one of the expected sql types"
+    )]
+    pub trait MultirangeOrNullableMultirange {
+        type Inner: SingleValue;
+        type Range: SingleValue;
+    }
+
+    impl<ST: SingleValue> MultirangeOrNullableMultirange for Multirange<ST> {
+        type Inner = ST;
+        type Range = Range<ST>;
+    }
+    impl<ST: SingleValue> MultirangeOrNullableMultirange for Nullable<Multirange<ST>> {
+        type Inner = ST;
+        type Range = Nullable<Range<ST>>;
+    }
 
     /// Marker trait used to implement `PgRangeExpressionMethods` on the appropriate
     /// types. Once coherence takes associated types into account, we can remove