impl PartialEq<{str,String}> for {Path,PathBuf}

Comparison of paths and strings is expected to be possible and needed
e.g. in tests. This change adds the impls os `PartialEq` between strings
and paths, both owned and unsized, in both directions.

ACP: rust-lang/libs-team#151

Author: Kixunil

library/std/src/path.rs

@@ -1885,6 +1885,38 @@ impl cmp::PartialEq for PathBuf {
     }
 }
 
+#[stable(feature = "eq-str-for-path", since = "CURRENT_RUSTC_VERSION")]
+impl cmp::PartialEq<str> for PathBuf {
+    #[inline]
+    fn eq(&self, other: &str) -> bool {
+        &*self == other
+    }
+}
+
+#[stable(feature = "eq-str-for-path", since = "CURRENT_RUSTC_VERSION")]
+impl cmp::PartialEq<PathBuf> for str {
+    #[inline]
+    fn eq(&self, other: &PathBuf) -> bool {
+        other == self
+    }
+}
+
+#[stable(feature = "eq-str-for-path", since = "CURRENT_RUSTC_VERSION")]
+impl cmp::PartialEq<String> for PathBuf {
+    #[inline]
+    fn eq(&self, other: &String) -> bool {
+        **self == **other
+    }
+}
+
+#[stable(feature = "eq-str-for-path", since = "CURRENT_RUSTC_VERSION")]
+impl cmp::PartialEq<PathBuf> for String {
+    #[inline]
+    fn eq(&self, other: &PathBuf) -> bool {
+        other == self
+    }
+}
+
 #[stable(feature = "rust1", since = "1.0.0")]
 impl Hash for PathBuf {
     fn hash<H: Hasher>(&self, h: &mut H) {
@@ -3003,6 +3035,39 @@ impl cmp::PartialEq for Path {
     }
 }
 
+#[stable(feature = "eq-str-for-path", since = "CURRENT_RUSTC_VERSION")]
+impl cmp::PartialEq<str> for Path {
+    #[inline]
+    fn eq(&self, other: &str) -> bool {
+        let other: &OsStr = other.as_ref();
+        self == other
+    }
+}
+
+#[stable(feature = "eq-str-for-path", since = "CURRENT_RUSTC_VERSION")]
+impl cmp::PartialEq<Path> for str {
+    #[inline]
+    fn eq(&self, other: &Path) -> bool {
+        other == self
+    }
+}
+
+#[stable(feature = "eq-str-for-path", since = "CURRENT_RUSTC_VERSION")]
+impl cmp::PartialEq<String> for Path {
+    #[inline]
+    fn eq(&self, other: &String) -> bool {
+        self == &*other
+    }
+}
+
+#[stable(feature = "eq-str-for-path", since = "CURRENT_RUSTC_VERSION")]
+impl cmp::PartialEq<Path> for String {
+    #[inline]
+    fn eq(&self, other: &Path) -> bool {
+        other == self
+    }
+}
+
 #[stable(feature = "rust1", since = "1.0.0")]
 impl Hash for Path {
     fn hash<H: Hasher>(&self, h: &mut H) {

src/test/ui/inference/issue-72616.stderr

@@ -6,8 +6,10 @@ LL |         if String::from("a") == "a".try_into().unwrap() {}
    |                              |
    |                              type must be known at this point
    |
-   = note: multiple `impl`s satisfying `String: PartialEq<_>` found in the `alloc` crate:
+   = note: multiple `impl`s satisfying `String: PartialEq<_>` found in the following crates: `alloc`, `std`:
            - impl PartialEq for String;
+           - impl PartialEq<Path> for String;
+           - impl PartialEq<PathBuf> for String;
            - impl<'a, 'b> PartialEq<&'a str> for String;
            - impl<'a, 'b> PartialEq<Cow<'a, str>> for String;
            - impl<'a, 'b> PartialEq<str> for String;