Rollup merge of rust-lang#140956 - Kixunil:impl-partialeq-str-for-path, r=Amanieu

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

This is a revival of rust-lang#105877

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: Zalathar

library/std/src/path.rs

@@ -2105,6 +2105,38 @@ impl 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) {
@@ -3366,6 +3398,39 @@ impl 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) {

tests/ui/inference/issue-72616.stderr

@@ -6,14 +6,10 @@ LL |         if String::from("a") == "a".try_into().unwrap() {}
    |                              |
    |                              type must be known at this point
    |
-   = note: cannot satisfy `String: PartialEq<_>`
-   = help: the following types implement trait `PartialEq<Rhs>`:
-             `String` implements `PartialEq<&str>`
-             `String` implements `PartialEq<ByteStr>`
-             `String` implements `PartialEq<ByteString>`
-             `String` implements `PartialEq<Cow<'_, str>>`
-             `String` implements `PartialEq<str>`
-             `String` implements `PartialEq`
+   = 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;
 help: try using a fully qualified path to specify the expected types
    |
 LL -         if String::from("a") == "a".try_into().unwrap() {}

tests/ui/suggestions/partialeq_suggest_swap_on_e0277.stderr

@@ -10,6 +10,8 @@ LL |     String::from("Girls Band Cry") == T(String::from("Girls Band Cry"));
              `String` implements `PartialEq<ByteStr>`
              `String` implements `PartialEq<ByteString>`
              `String` implements `PartialEq<Cow<'_, str>>`
+             `String` implements `PartialEq<Path>`
+             `String` implements `PartialEq<PathBuf>`
              `String` implements `PartialEq<str>`
              `String` implements `PartialEq`
    = note: `T` implements `PartialEq<String>`