fix(parser): Improve AnyValue debug output

src/parser/matches/any_value.rs

@@ -1,15 +1,98 @@
-#[derive(Clone, Debug)]
+#[derive(Clone)]
 pub struct AnyValue {
     inner: std::sync::Arc<dyn std::any::Any + Send + Sync + 'static>,
+    // While we can extract `TypeId` from `inner`, the debug repr is of a number, so let's track
+    // the type_name in debug builds.
+    id: AnyValueId,
 }
 
 impl AnyValue {
-    pub(crate) fn new(inner: impl std::any::Any + Send + Sync + 'static) -> Self {
+    pub(crate) fn new<V: std::any::Any + Send + Sync + 'static>(inner: V) -> Self {
+        let id = AnyValueId::of::<V>();
         let inner = std::sync::Arc::new(inner);
-        Self { inner }
+        Self { inner, id }
     }
 
     pub(crate) fn downcast_ref<T: std::any::Any>(&self) -> Option<&T> {
         self.inner.downcast_ref::<T>()
     }
 }
+
+impl std::fmt::Debug for AnyValue {
+    fn fmt(&self, f: &mut std::fmt::Formatter<'_>) -> Result<(), std::fmt::Error> {
+        f.debug_struct("AnyValue").field("inner", &self.id).finish()
+    }
+}
+
+#[derive(Copy, Clone)]
+pub(crate) struct AnyValueId {
+    type_id: std::any::TypeId,
+    #[cfg(debug_assertions)]
+    type_name: &'static str,
+}
+
+impl AnyValueId {
+    pub(crate) fn of<A: ?Sized + 'static>() -> Self {
+        Self {
+            type_id: std::any::TypeId::of::<A>(),
+            #[cfg(debug_assertions)]
+            type_name: std::any::type_name::<A>(),
+        }
+    }
+}
+
+impl PartialEq for AnyValueId {
+    fn eq(&self, other: &Self) -> bool {
+        self.type_id == other.type_id
+    }
+}
+
+impl Eq for AnyValueId {}
+
+impl PartialOrd for AnyValueId {
+    fn partial_cmp(&self, other: &Self) -> Option<std::cmp::Ordering> {
+        self.type_id.partial_cmp(&other.type_id)
+    }
+}
+
+impl Ord for AnyValueId {
+    fn cmp(&self, other: &Self) -> std::cmp::Ordering {
+        self.type_id.cmp(&other.type_id)
+    }
+}
+
+impl std::hash::Hash for AnyValueId {
+    fn hash<H: std::hash::Hasher>(&self, state: &mut H) {
+        self.type_id.hash(state);
+    }
+}
+
+impl std::fmt::Debug for AnyValueId {
+    fn fmt(&self, f: &mut std::fmt::Formatter<'_>) -> Result<(), std::fmt::Error> {
+        #[cfg(not(debug_assertions))]
+        {
+            self.type_id.fmt(f)
+        }
+        #[cfg(debug_assertions)]
+        {
+            f.debug_struct(self.type_name).finish()
+        }
+    }
+}
+
+impl<'a, A: ?Sized + 'static> From<&'a A> for AnyValueId {
+    fn from(_: &'a A) -> Self {
+        Self::of::<A>()
+    }
+}
+
+#[cfg(test)]
+mod test {
+    use super::*;
+
+    #[test]
+    #[cfg(debug_assertions)]
+    fn debug_impl() {
+        assert_eq!(format!("{:?}", AnyValue::new(5)), "AnyValue { inner: i32 }");
+    }
+}