Rollup merge of #61003 - nnethercote:rm-InternedString-PartialEq-impls, r=petrochenkov

Remove impls for `InternedString`/string equality.

`Symbol` received the same treatment in #60630.

Also, we can derive `PartialEq` for `InternedString`.

r? @petrochenkov

src/libsyntax_pos/symbol.rs

@@ -1147,7 +1147,7 @@ impl Encodable for LocalInternedString {
 /// assert_ne!(Symbol::gensym("x"), Symbol::gensym("x"))
 /// assert_eq!(Symbol::gensym("x").as_interned_str(), Symbol::gensym("x").as_interned_str())
 /// ```
-#[derive(Clone, Copy, Eq)]
+#[derive(Clone, Copy, PartialEq, Eq)]
 pub struct InternedString {
     symbol: Symbol,
 }
@@ -1212,42 +1212,6 @@ impl Ord for InternedString {
     }
 }
 
-impl<T: std::ops::Deref<Target = str>> PartialEq<T> for InternedString {
-    fn eq(&self, other: &T) -> bool {
-        self.with(|string| string == other.deref())
-    }
-}
-
-impl PartialEq<InternedString> for InternedString {
-    fn eq(&self, other: &InternedString) -> bool {
-        self.symbol == other.symbol
-    }
-}
-
-impl PartialEq<InternedString> for str {
-    fn eq(&self, other: &InternedString) -> bool {
-        other.with(|string| self == string)
-    }
-}
-
-impl<'a> PartialEq<InternedString> for &'a str {
-    fn eq(&self, other: &InternedString) -> bool {
-        other.with(|string| *self == string)
-    }
-}
-
-impl PartialEq<InternedString> for String {
-    fn eq(&self, other: &InternedString) -> bool {
-        other.with(|string| self == string)
-    }
-}
-
-impl<'a> PartialEq<InternedString> for &'a String {
-    fn eq(&self, other: &InternedString) -> bool {
-        other.with(|string| *self == string)
-    }
-}
-
 impl fmt::Debug for InternedString {
     fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
         self.with(|str| fmt::Debug::fmt(&str, f))