fix(clinvoice_adapter_postgres): workaround for rust-lang/rust#39959

Author: Iron-E

crates/adapters/clinvoice_adapter_postgres/src/fmt/location_recursive_cte.rs

@@ -1,5 +1,3 @@
-mod display;
-
 use core::fmt::Display;
 
 use clinvoice_adapter::fmt::SnakeCase;
@@ -12,54 +10,34 @@ use clinvoice_adapter::fmt::SnakeCase;
 /// Created to avoid using `format!` every time this pattern was required, thus eagerly allocating
 /// a [`String`] even if it was only needed for pushing to another [`String`].
 #[derive(Copy, Clone, Debug, Eq, Hash, Ord, PartialEq, PartialOrd)]
-pub(crate) struct PgLocationRecursiveCte<TCurrent, TPrev>(SnakeCase<TPrev, TCurrent>)
-where
-	TCurrent: Display,
-	TPrev: Display;
+pub(crate) struct PgLocationRecursiveCte;
 
-impl<TCurrent, TPrev> PgLocationRecursiveCte<TCurrent, TPrev>
-where
-	TCurrent: Display,
-	TPrev: Display,
+impl PgLocationRecursiveCte
 {
 	/// # Summary
 	///
-	/// Return the previous occurance of the [`PgLocationRecursiveCte`], if there is one.
-	pub(crate) const fn prev(&self) -> Option<&TPrev>
+	/// Create a new recursive CTE identifier for a [`PgLocation`].
+	pub(crate) const fn new() -> SnakeCase<&'static str, &'static str>
 	{
-		if let Some((left, _)) = self.0.slice_end()
-		{
-			return Some(left);
-		}
-
-		None
+		SnakeCase::new("location")
 	}
 
 	/// # Summary
 	///
 	/// Get the [`PgLocationRecursiveCte`] representing the [`Location`](clinvoice_schema::Location) this one.
-	pub(crate) fn outer(self) -> PgLocationRecursiveCte<&'static str, SnakeCase<TPrev, TCurrent>>
-	{
-		PgLocationRecursiveCte(self.0.push("outer"))
-	}
-}
-
-impl PgLocationRecursiveCte<&'static str, &'static str>
-{
-	/// # Summary
-	///
-	/// Create a new recursive CTE identifier for a [`PgLocation`].
-	pub(crate) const fn new() -> Self
+	pub(crate) const fn outer<T>(t: T) -> SnakeCase<T, &'static str>
+	where
+		T: Display,
 	{
-		Self(SnakeCase::new("location"))
+		SnakeCase::Body(t, "outer")
 	}
 
 	/// # Summary
 	///
 	/// The ident used to refer to the rows matching some [`MatchLocation`] at the end of a `WITH
 	/// RECURSIVE`.
-	pub(crate) const fn report() -> Self
+	pub(crate) const fn report() -> SnakeCase<&'static str, &'static str>
 	{
-		Self(SnakeCase::new("location_report"))
+		SnakeCase::new("location_report")
 	}
 }

crates/adapters/clinvoice_adapter_postgres/src/fmt/location_recursive_cte/display.rs

@@ -33,8 +33,9 @@ impl PgLocation
 		/// Generate multiple Common Table Expressions for a recursive query.
 		fn generate_cte<TCurrent, TPrev, const FIRST: bool>(
 			query: &mut QueryBuilder<Postgres>,
-			ident: PgLocationRecursiveCte<TCurrent, TPrev>,
+			ident: TCurrent, /* HACK: this parameter should be `ident: SnakeCase<TPrev, TCurrent>` after rust-lang/rust#39959 */
 			match_condition: &MatchLocation,
+			prev: Option<TPrev>, /* HACK: this parameter is necessary because we can't use `ident: SnakeCase` because of rust-lang/rust#39959 */
 		) where
 			TCurrent: Display,
 			TPrev: Display,
@@ -58,11 +59,11 @@ impl PgLocation
 					.push("FROM locations")
 					.push(ALIAS_OUTER);
 
-				if let Some(prev) = ident.prev()
+				if let Some(p) = prev
 				{
 					separated
 						.push("JOIN")
-						.push(prev)
+						.push(p)
 						.push(ALIAS_INNER)
 						.push("ON (")
 						.push_unseparated(outer_columns.id)
@@ -103,7 +104,13 @@ impl PgLocation
 				MatchOuterLocation::Some(ref outer) =>
 				{
 					query.push(',');
-					generate_cte::<_, _, false>(query, ident.outer(), outer)
+					generate_cte::<_, _, false>(
+						query,
+						// HACK: remove `.to_string()` after rust-lang/rust#39959
+						PgLocationRecursiveCte::outer(&ident).to_string(),
+						outer,
+						Some(&ident),
+					)
 				},
 				MatchOuterLocation::Any | MatchOuterLocation::None =>
 				{
@@ -148,7 +155,12 @@ impl PgLocation
 
 		let mut query = QueryBuilder::new("WITH RECURSIVE ");
 
-		generate_cte::<_, _, true>(&mut query, PgLocationRecursiveCte::new(), match_condition);
+		generate_cte::<_, _, true>(
+			&mut query,
+			PgLocationRecursiveCte::new(),
+			match_condition,
+			None::<&str>,
+		);
 
 		query.push(' ');
 		query