Discourage comparing str with Encoding using PartialEq

Author: madsmtm

objc2-encode/CHANGELOG.md

@@ -11,6 +11,10 @@ The format is based on [Keep a Changelog](https://keepachangelog.com/en/1.0.0/).
   `Encoding::equivalent_to_start_of_str` methods for more precise comparison
   semantics.
 
+### Changed
+* Discourage comparing `str` with `Encoding` using `PartialEq`. This trait
+  impl might get removed in a future version.
+
 
 ## 2.0.0-beta.0 - 2021-11-22
 

objc2-encode/src/encoding.rs

@@ -195,16 +195,38 @@ impl fmt::Display for Encoding<'_> {
     }
 }
 
+// TODO: Deprecate and remove these PartialEq impls
+
+/// Partial equality between an [`Encoding`] and a [`str`].
+///
+/// Using this is heavily discouraged, since it is not transitive; use
+/// [`Encoding::equivalent_to_str`] instead for more correct semantics.
 impl PartialEq<str> for Encoding<'_> {
+    /// Using this is discouraged.
     fn eq(&self, other: &str) -> bool {
         self.equivalent_to_str(other)
     }
+
+    /// Using this is discouraged.
+    fn ne(&self, other: &str) -> bool {
+        !self.eq(other)
+    }
 }
 
+/// Partial equality between an [`Encoding`] and a [`str`].
+///
+/// Using this is heavily discouraged, since it is not transitive; use
+/// [`Encoding::equivalent_to_str`] instead for more correct semantics.
 impl PartialEq<Encoding<'_>> for str {
+    /// Using this is discouraged.
     fn eq(&self, other: &Encoding<'_>) -> bool {
         other.equivalent_to_str(self)
     }
+
+    /// Using this is discouraged.
+    fn ne(&self, other: &Encoding<'_>) -> bool {
+        !self.eq(other)
+    }
 }
 
 #[cfg(test)]