diff --git a/src/rcore.rs b/src/rcore.rs
index 1f0ef02..a1c9465 100644
--- a/src/rcore.rs
+++ b/src/rcore.rs
@@ -89,6 +89,8 @@ pub type Mtbl<'a, Ctx, F> = <F as Factory<'a, Ctx>>::Mtbl;
 /// [`Factory::ParseError`]. Mostly useful for `type` definitions.
 pub type ParseError<'a, Ctx, F> = <F as Factory<'a, Ctx>>::ParseError;
 
+/// [`Factory::ParseError`] associated with the [`Mentionable`].
+/// Mostly useful for `type` definitions.
 pub type ParseErrorA<'a, Ctx, A> = ParseError<'a, Ctx, Fctr<'a, Ctx, A>>;
 
 /// Extension trait for factories.