value-bag distinct

Signed-off-by: tison <wander4096@gmail.com>

src/kv/value.rs

@@ -3,6 +3,7 @@
 //! This module defines the [`Value`] type and supporting APIs for
 //! capturing and serializing them.
 
+use alloc::borrow::Cow;
 use std::fmt;
 
 pub use crate::kv::Error;
@@ -432,20 +433,21 @@ mod std_support {
         }
     }
 
-    impl<'v> Value<'v> {
-        /// Try to convert this value into a string.
-        pub fn to_cow_str(&self) -> Option<Cow<'v, str>> {
-            self.inner.to_str()
-        }
-    }
-
     impl<'v> From<&'v String> for Value<'v> {
         fn from(v: &'v String) -> Self {
             Value::from(&**v)
         }
     }
 }
 
+#[cfg(all(feature = "std", feature = "value-bag"))]
+impl<'v> Value<'v> {
+    /// Try to convert this value into a string.
+    pub fn to_cow_str(&self) -> Option<Cow<'v, str>> {
+        self.inner.to_str()
+    }
+}
+
 /// A visitor for a [`Value`].
 ///
 /// Also see [`Value`'s documentation on seralization]. Value visitors are a simple alternative

src/lib.rs

@@ -389,6 +389,7 @@ compile_error!("multiple release_max_level_* features set");
 
 #[cfg(all(not(feature = "std"), not(test)))]
 extern crate core as std;
+extern crate alloc;
 
 use std::cfg;
 #[cfg(feature = "std")]