Implement Value for Valuable expose in tracing

tracing-core/src/field.rs

@@ -181,7 +181,7 @@ pub struct Iter {
 pub trait Visit {
     /// Visits an arbitrary value from Valuable
     #[cfg(feature = "valuable")]
-    fn record_value(&mut self, field: &Field, value: &(dyn valuable::Valuable)) {
+    fn record_value(&mut self, field: &Field, value: &dyn valuable::Valuable) {
         self.record_debug(field, &value)
     }
 
@@ -429,6 +429,17 @@ impl Value for dyn std::error::Error + 'static {
     }
 }
 
+#[cfg(feature = "valuable")]
+impl crate::sealed::Sealed for dyn valuable::Valuable {}
+
+#[cfg(feature = "valuable")]
+#[cfg_attr(docsrs, doc(cfg(feature = "valuable")))]
+impl Value for dyn valuable::Valuable {
+    fn record(&self, key: &Field, visitor: &mut dyn Visit) {
+        visitor.record_value(key, self)
+    }
+}
+
 impl<'a, T: ?Sized> crate::sealed::Sealed for &'a T where T: Value + crate::sealed::Sealed + 'a {}
 
 impl<'a, T: ?Sized> Value for &'a T

tracing/Cargo.toml

@@ -66,6 +66,7 @@ alloc = ["tracing-core/alloc"]
 std = ["tracing-core/std", "alloc"]
 log-always = ["log"]
 attributes = ["tracing-attributes"]
+valuable = ["tracing-core/valuable"]
 
 [[bench]]
 name = "subscriber"