refactor: improve type param names, docs & more of casting

5 files changed, 57 insertions, 74 deletions

diff --git a/src/libs/intertrait/cast/arc.rs b/src/libs/intertrait/cast/arc.rs
index 6d3867c..a1b2c30 100644
--- a/src/libs/intertrait/cast/arc.rs
+++ b/src/libs/intertrait/cast/arc.rs
@@ -17,31 +17,27 @@ use crate::libs::intertrait::{get_caster, CastFromSync};
 
 pub trait CastArc
 {
-    /// Casts an `Arc` for this trait into that for type `OtherTrait`.
-    fn cast<OtherTrait: ?Sized + 'static>(
-        self: Arc<Self>,
-    ) -> Result<Arc<OtherTrait>, CastError>;
+    /// Casts an `Arc` with `Self` into an `Arc` with `Dest`.
+    fn cast<Dest: ?Sized + 'static>(self: Arc<Self>) -> Result<Arc<Dest>, CastError>;
 }
 
 /// A blanket implementation of `CastArc` for traits extending `CastFrom`, `Sync`, and
 /// `Send`.
 impl<CastFromSelf: ?Sized + CastFromSync> CastArc for CastFromSelf
 {
-    fn cast<OtherTrait: ?Sized + 'static>(
-        self: Arc<Self>,
-    ) -> Result<Arc<OtherTrait>, CastError>
+    fn cast<Dest: ?Sized + 'static>(self: Arc<Self>) -> Result<Arc<Dest>, CastError>
     {
-        let caster = get_caster::<OtherTrait>((*self).type_id())
-            .map_err(CastError::GetCasterFailed)?;
+        let caster =
+            get_caster::<Dest>((*self).type_id()).map_err(CastError::GetCasterFailed)?;
 
         let cast_arc = caster
             .opt_cast_arc
-            .ok_or(CastError::NotArcCastable(type_name::<OtherTrait>()))?;
+            .ok_or(CastError::NotArcCastable(type_name::<Dest>()))?;
 
         cast_arc(self.arc_any()).map_err(|err| CastError::CastFailed {
             source: err,
             from: type_name::<Self>(),
-            to: type_name::<OtherTrait>(),
+            to: type_name::<Dest>(),
         })
     }
 }
diff --git a/src/libs/intertrait/cast/box.rs b/src/libs/intertrait/cast/box.rs
index 0e160f4..fcd5f70 100644
--- a/src/libs/intertrait/cast/box.rs
+++ b/src/libs/intertrait/cast/box.rs
@@ -17,26 +17,22 @@ use crate::libs::intertrait::{get_caster, CastFrom};
 
 pub trait CastBox
 {
-    /// Casts a box to this trait into that of type `OtherTrait`.
-    fn cast<OtherTrait: ?Sized + 'static>(
-        self: Box<Self>,
-    ) -> Result<Box<OtherTrait>, CastError>;
+    /// Casts a `Box` with `Self` into a `Box` with `Dest`.
+    fn cast<Dest: ?Sized + 'static>(self: Box<Self>) -> Result<Box<Dest>, CastError>;
 }
 
 /// A blanket implementation of `CastBox` for traits extending `CastFrom`.
 impl<CastFromSelf: ?Sized + CastFrom> CastBox for CastFromSelf
 {
-    fn cast<OtherTrait: ?Sized + 'static>(
-        self: Box<Self>,
-    ) -> Result<Box<OtherTrait>, CastError>
+    fn cast<Dest: ?Sized + 'static>(self: Box<Self>) -> Result<Box<Dest>, CastError>
     {
-        let caster = get_caster::<OtherTrait>((*self).type_id())
-            .map_err(CastError::GetCasterFailed)?;
+        let caster =
+            get_caster::<Dest>((*self).type_id()).map_err(CastError::GetCasterFailed)?;
 
         (caster.cast_box)(self.box_any()).map_err(|err| CastError::CastFailed {
             source: err,
             from: type_name::<Self>(),
-            to: type_name::<OtherTrait>(),
+            to: type_name::<Dest>(),
         })
     }
 }
diff --git a/src/libs/intertrait/cast/error.rs b/src/libs/intertrait/cast/error.rs
index e6d86a5..d253fc5 100644
--- a/src/libs/intertrait/cast/error.rs
+++ b/src/libs/intertrait/cast/error.rs
@@ -6,7 +6,7 @@ pub enum CastError
     #[error("Failed to get caster")]
     GetCasterFailed(#[from] GetCasterError),
 
-    #[error("Failed to cast from trait {from} to trait {to}")]
+    #[error("Failed to cast from {from} to {to}")]
     CastFailed
     {
         #[source]
@@ -15,6 +15,6 @@ pub enum CastError
         to: &'static str,
     },
 
-    #[error("Trait '{0}' can't be cast to Arc")]
+    #[error("'{0}' can't be cast to an Arc")]
     NotArcCastable(&'static str),
 }
diff --git a/src/libs/intertrait/cast/rc.rs b/src/libs/intertrait/cast/rc.rs
index 906490d..8567d1e 100644
--- a/src/libs/intertrait/cast/rc.rs
+++ b/src/libs/intertrait/cast/rc.rs
@@ -17,26 +17,22 @@ use crate::libs::intertrait::{get_caster, CastFrom};
 
 pub trait CastRc
 {
-    /// Casts an `Rc` for this trait into that for type `OtherTrait`.
-    fn cast<OtherTrait: ?Sized + 'static>(
-        self: Rc<Self>,
-    ) -> Result<Rc<OtherTrait>, CastError>;
+    /// Casts an `Rc` with `Self `into a `Rc` with `Dest`.
+    fn cast<Dest: ?Sized + 'static>(self: Rc<Self>) -> Result<Rc<Dest>, CastError>;
 }
 
 /// A blanket implementation of `CastRc` for traits extending `CastFrom`.
 impl<CastFromSelf: ?Sized + CastFrom> CastRc for CastFromSelf
 {
-    fn cast<OtherTrait: ?Sized + 'static>(
-        self: Rc<Self>,
-    ) -> Result<Rc<OtherTrait>, CastError>
+    fn cast<Dest: ?Sized + 'static>(self: Rc<Self>) -> Result<Rc<Dest>, CastError>
     {
-        let caster = get_caster::<OtherTrait>((*self).type_id())
-            .map_err(CastError::GetCasterFailed)?;
+        let caster =
+            get_caster::<Dest>((*self).type_id()).map_err(CastError::GetCasterFailed)?;
 
         (caster.cast_rc)(self.rc_any()).map_err(|err| CastError::CastFailed {
             source: err,
             from: type_name::<Self>(),
-            to: type_name::<OtherTrait>(),
+            to: type_name::<Dest>(),
         })
     }
 }
diff --git a/src/libs/intertrait/mod.rs b/src/libs/intertrait/mod.rs
index 4a9322f..d2ace67 100644
--- a/src/libs/intertrait/mod.rs
+++ b/src/libs/intertrait/mod.rs
@@ -33,18 +33,14 @@ pub mod cast;
 
 pub type BoxedCaster = Box<dyn Any + Send + Sync>;
 
-/// A distributed slice gathering constructor functions for [`Caster<T>`]s.
+/// A distributed slice gathering constructor functions for [`Caster`]s.
 ///
 /// A constructor function returns `TypeId` of a concrete type involved in the casting
-/// and a `Box` of a trait object backed by a [`Caster<T>`].
-///
-/// [`Caster<T>`]: ./struct.Caster.html
+/// and a `Box` of a type or trait backed by a [`Caster`].
 #[distributed_slice]
 pub static CASTERS: [fn() -> (TypeId, BoxedCaster)] = [..];
 
-/// A `HashMap` mapping `TypeId` of a [`Caster<T>`] to an instance of it.
-///
-/// [`Caster<T>`]: ./struct.Caster.html
+/// A `HashMap` mapping `TypeId` of a [`Caster`] to an instance of it.
 static CASTER_MAP: Lazy<AHashMap<(TypeId, TypeId), BoxedCaster>> = Lazy::new(|| {
     CASTERS
         .iter()
@@ -56,37 +52,36 @@ static CASTER_MAP: Lazy<AHashMap<(TypeId, TypeId), BoxedCaster>> = Lazy::new(||
         .collect()
 });
 
-type CastBoxFn<Trait> = fn(from: Box<dyn Any>) -> Result<Box<Trait>, CasterError>;
+type CastBoxFn<Dest> = fn(from: Box<dyn Any>) -> Result<Box<Dest>, CasterError>;
 
-type CastRcFn<Trait> = fn(from: Rc<dyn Any>) -> Result<Rc<Trait>, CasterError>;
+type CastRcFn<Dest> = fn(from: Rc<dyn Any>) -> Result<Rc<Dest>, CasterError>;
 
-type CastArcFn<Trait> =
-    fn(from: Arc<dyn Any + Sync + Send + 'static>) -> Result<Arc<Trait>, CasterError>;
+type CastArcFn<Dest> =
+    fn(from: Arc<dyn Any + Sync + Send + 'static>) -> Result<Arc<Dest>, CasterError>;
 
-/// A `Caster` knows how to cast a reference to or `Box` of a trait object for `Any`
-/// to a trait object of trait `Trait`. Each `Caster` instance is specific to a concrete
-/// type. That is, it knows how to cast to single specific trait implemented by single
-/// specific type.
-pub struct Caster<Trait: ?Sized + 'static>
+/// A `Caster` knows how to cast a type or trait to the type or trait `Dest`. Each
+/// `Caster` instance is specific to a concrete type. That is, it knows how to cast to
+/// single specific type or trait implemented by single specific type.
+pub struct Caster<Dest: ?Sized + 'static>
 {
-    /// Casts a `Box` holding a trait object for `Any` to another `Box` holding a trait
-    /// object for trait `Trait`.
-    pub cast_box: CastBoxFn<Trait>,
+    /// Casts a `Box` holding a type or trait object for `Any` to another `Box` holding a
+    /// type or trait `Dest`.
+    pub cast_box: CastBoxFn<Dest>,
 
-    /// Casts an `Rc` holding a trait object for `Any` to another `Rc` holding a trait
-    /// object for trait `Trait`.
-    pub cast_rc: CastRcFn<Trait>,
+    /// Casts an `Rc` holding a type or trait for `Any` to another `Rc` holding a type or
+    /// trait `Dest`.
+    pub cast_rc: CastRcFn<Dest>,
 
-    /// Casts an `Arc` holding a trait object for `Any + Sync + Send + 'static`
-    /// to another `Arc` holding a trait object for trait `Trait`.
-    pub opt_cast_arc: Option<CastArcFn<Trait>>,
+    /// Casts an `Arc` holding a type or trait for `Any + Sync + Send + 'static` to
+    /// another `Arc` holding a type or trait for `Dest`.
+    pub opt_cast_arc: Option<CastArcFn<Dest>>,
 }
 
-impl<Trait: ?Sized + 'static> Caster<Trait>
+impl<Dest: ?Sized + 'static> Caster<Dest>
 {
-    pub fn new(cast_box: CastBoxFn<Trait>, cast_rc: CastRcFn<Trait>) -> Caster<Trait>
+    pub fn new(cast_box: CastBoxFn<Dest>, cast_rc: CastRcFn<Dest>) -> Caster<Dest>
     {
-        Caster::<Trait> {
+        Caster::<Dest> {
             cast_box,
             cast_rc,
             opt_cast_arc: None,
@@ -95,12 +90,12 @@ impl<Trait: ?Sized + 'static> Caster<Trait>
 
     #[allow(clippy::similar_names)]
     pub fn new_sync(
-        cast_box: CastBoxFn<Trait>,
-        cast_rc: CastRcFn<Trait>,
-        cast_arc: CastArcFn<Trait>,
-    ) -> Caster<Trait>
+        cast_box: CastBoxFn<Dest>,
+        cast_rc: CastRcFn<Dest>,
+        cast_arc: CastArcFn<Dest>,
+    ) -> Caster<Dest>
     {
-        Caster::<Trait> {
+        Caster::<Dest> {
             cast_box,
             cast_rc,
             opt_cast_arc: Some(cast_arc),
@@ -121,18 +116,18 @@ pub enum CasterError
     CastArcFailed,
 }
 
-/// Returns a `Caster<S, Trait>` from a concrete type `S` to a trait `Trait` implemented
-/// by it.
-fn get_caster<Trait: ?Sized + 'static>(
+/// Returns a `Caster<Dest>` from a concrete type with the id `type_id` to a type or trait
+/// `Dest`.
+fn get_caster<Dest: ?Sized + 'static>(
     type_id: TypeId,
-) -> Result<&'static Caster<Trait>, GetCasterError>
+) -> Result<&'static Caster<Dest>, GetCasterError>
 {
     let any_caster = CASTER_MAP
-        .get(&(type_id, TypeId::of::<Caster<Trait>>()))
+        .get(&(type_id, TypeId::of::<Caster<Dest>>()))
         .ok_or(GetCasterError::NotFound)?;
 
     any_caster
-        .downcast_ref::<Caster<Trait>>()
+        .downcast_ref::<Caster<Dest>>()
         .ok_or(GetCasterError::DowncastFailed)
 }
 
@@ -186,7 +181,7 @@ pub trait CastFromSync: CastFrom + Sync + Send + 'static
     fn arc_any(self: Arc<Self>) -> Arc<dyn Any + Sync + Send + 'static>;
 }
 
-impl<Trait: Sized + Any + 'static> CastFrom for Trait
+impl<Source: Sized + Any + 'static> CastFrom for Source
 {
     fn box_any(self: Box<Self>) -> Box<dyn Any>
     {
@@ -212,7 +207,7 @@ impl CastFrom for dyn Any + 'static
     }
 }
 
-impl<Trait: Sized + Sync + Send + 'static> CastFromSync for Trait
+impl<Source: Sized + Sync + Send + 'static> CastFromSync for Source
 {
     fn arc_any(self: Arc<Self>) -> Arc<dyn Any + Sync + Send + 'static>
     {