Rollup of 4 pull requests

src/libcore/marker.rs

@@ -709,6 +709,7 @@ unsafe impl<T: ?Sized> Freeze for &mut T {}
 /// So this, for example, can only be done on types implementing `Unpin`:
 ///
 /// ```rust
+/// # #![allow(unused_must_use)]
 /// use std::mem;
 /// use std::pin::Pin;
 ///

src/libcore/mem/mod.rs

@@ -808,6 +808,7 @@ pub fn take<T: Default>(dest: &mut T) -> T {
 /// [`Clone`]: ../../std/clone/trait.Clone.html
 #[inline]
 #[stable(feature = "rust1", since = "1.0.0")]
+#[must_use = "if you don't need the old value, you can just assign the new value directly"]
 pub fn replace<T>(dest: &mut T, mut src: T) -> T {
     swap(dest, &mut src);
     src

src/libcore/str/mod.rs

@@ -3010,6 +3010,12 @@ impl str {
     ///
     /// Returns `false` if it does not.
     ///
+    /// The [pattern] can be a `&str`, [`char`], a slice of [`char`]s, or a
+    /// function or closure that determines if a character matches.
+    ///
+    /// [`char`]: primitive.char.html
+    /// [pattern]: str/pattern/index.html
+    ///
     /// # Examples
     ///
     /// Basic usage:
@@ -3031,6 +3037,12 @@ impl str {
     ///
     /// Returns `false` if it does not.
     ///
+    /// The [pattern] can be a `&str`, [`char`], a slice of [`char`]s, or a
+    /// function or closure that determines if a character matches.
+    ///
+    /// [`char`]: primitive.char.html
+    /// [pattern]: str/pattern/index.html
+    ///
     /// # Examples
     ///
     /// Basic usage:
@@ -3051,6 +3063,12 @@ impl str {
     ///
     /// Returns `false` if it does not.
     ///
+    /// The [pattern] can be a `&str`, [`char`], a slice of [`char`]s, or a
+    /// function or closure that determines if a character matches.
+    ///
+    /// [`char`]: primitive.char.html
+    /// [pattern]: str/pattern/index.html
+    ///
     /// # Examples
     ///
     /// Basic usage:
@@ -3074,10 +3092,12 @@ impl str {
     ///
     /// Returns [`None`] if the pattern doesn't match.
     ///
-    /// The pattern can be a `&str`, [`char`], or a closure that determines if
-    /// a character matches.
+    /// The [pattern] can be a `&str`, [`char`], a slice of [`char`]s, or a
+    /// function or closure that determines if a character matches.
     ///
     /// [`None`]: option/enum.Option.html#variant.None
+    /// [`char`]: primitive.char.html
+    /// [pattern]: str/pattern/index.html
     ///
     /// # Examples
     ///
@@ -3121,10 +3141,12 @@ impl str {
     ///
     /// Returns [`None`] if the pattern doesn't match.
     ///
-    /// The pattern can be a `&str`, [`char`], or a closure that determines if
-    /// a character matches.
+    /// The [pattern] can be a `&str`, [`char`], a slice of [`char`]s, or a
+    /// function or closure that determines if a character matches.
     ///
     /// [`None`]: option/enum.Option.html#variant.None
+    /// [`char`]: primitive.char.html
+    /// [pattern]: str/pattern/index.html
     ///
     /// # Examples
     ///
@@ -3166,8 +3188,11 @@ impl str {
     /// An iterator over substrings of this string slice, separated by
     /// characters matched by a pattern.
     ///
-    /// The pattern can be any type that implements the Pattern trait. Notable
-    /// examples are `&str`, [`char`], and closures that determines the split.
+    /// The [pattern] can be a `&str`, [`char`], a slice of [`char`]s, or a
+    /// function or closure that determines if a character matches.
+    ///
+    /// [`char`]: primitive.char.html
+    /// [pattern]: str/pattern/index.html
     ///
     /// # Iterator behavior
     ///
@@ -3285,6 +3310,12 @@ impl str {
     /// `split` in that `split_inclusive` leaves the matched part as the
     /// terminator of the substring.
     ///
+    /// The [pattern] can be a `&str`, [`char`], a slice of [`char`]s, or a
+    /// function or closure that determines if a character matches.
+    ///
+    /// [`char`]: primitive.char.html
+    /// [pattern]: str/pattern/index.html
+    ///
     /// # Examples
     ///
     /// ```
@@ -3319,8 +3350,11 @@ impl str {
     /// An iterator over substrings of the given string slice, separated by
     /// characters matched by a pattern and yielded in reverse order.
     ///
-    /// The pattern can be any type that implements the Pattern trait. Notable
-    /// examples are `&str`, [`char`], and closures that determines the split.
+    /// The [pattern] can be a `&str`, [`char`], a slice of [`char`]s, or a
+    /// function or closure that determines if a character matches.
+    ///
+    /// [`char`]: primitive.char.html
+    /// [pattern]: str/pattern/index.html
     ///
     /// # Iterator behavior
     ///
@@ -3370,8 +3404,11 @@ impl str {
     /// An iterator over substrings of the given string slice, separated by
     /// characters matched by a pattern.
     ///
-    /// The pattern can be any type that implements the Pattern trait. Notable
-    /// examples are `&str`, [`char`], and closures that determines the split.
+    /// The [pattern] can be a `&str`, [`char`], a slice of [`char`]s, or a
+    /// function or closure that determines if a character matches.
+    ///
+    /// [`char`]: primitive.char.html
+    /// [pattern]: str/pattern/index.html
     ///
     /// Equivalent to [`split`], except that the trailing substring
     /// is skipped if empty.
@@ -3414,10 +3451,11 @@ impl str {
     /// An iterator over substrings of `self`, separated by characters
     /// matched by a pattern and yielded in reverse order.
     ///
-    /// The pattern can be any type that implements the Pattern trait. Notable
-    /// examples are `&str`, [`char`], and closures that determines the split.
-    /// Additional libraries might provide more complex patterns like
-    /// regular expressions.
+    /// The [pattern] can be a `&str`, [`char`], a slice of [`char`]s, or a
+    /// function or closure that determines if a character matches.
+    ///
+    /// [`char`]: primitive.char.html
+    /// [pattern]: str/pattern/index.html
     ///
     /// Equivalent to [`split`], except that the trailing substring is
     /// skipped if empty.
@@ -3462,8 +3500,11 @@ impl str {
     /// If `n` substrings are returned, the last substring (the `n`th substring)
     /// will contain the remainder of the string.
     ///
-    /// The pattern can be any type that implements the Pattern trait. Notable
-    /// examples are `&str`, [`char`], and closures that determines the split.
+    /// The [pattern] can be a `&str`, [`char`], a slice of [`char`]s, or a
+    /// function or closure that determines if a character matches.
+    ///
+    /// [`char`]: primitive.char.html
+    /// [pattern]: str/pattern/index.html
     ///
     /// # Iterator behavior
     ///
@@ -3512,8 +3553,11 @@ impl str {
     /// If `n` substrings are returned, the last substring (the `n`th substring)
     /// will contain the remainder of the string.
     ///
-    /// The pattern can be any type that implements the Pattern trait. Notable
-    /// examples are `&str`, [`char`], and closures that determines the split.
+    /// The [pattern] can be a `&str`, [`char`], a slice of [`char`]s, or a
+    /// function or closure that determines if a character matches.
+    ///
+    /// [`char`]: primitive.char.html
+    /// [pattern]: str/pattern/index.html
     ///
     /// # Iterator behavior
     ///
@@ -3557,8 +3601,11 @@ impl str {
     /// An iterator over the disjoint matches of a pattern within the given string
     /// slice.
     ///
-    /// The pattern can be a `&str`, [`char`], or a closure that determines if
-    /// a character matches.
+    /// The [pattern] can be a `&str`, [`char`], a slice of [`char`]s, or a
+    /// function or closure that determines if a character matches.
+    ///
+    /// [`char`]: primitive.char.html
+    /// [pattern]: str/pattern/index.html
     ///
     /// # Iterator behavior
     ///
@@ -3593,8 +3640,11 @@ impl str {
     /// An iterator over the disjoint matches of a pattern within this string slice,
     /// yielded in reverse order.
     ///
-    /// The pattern can be a `&str`, [`char`], or a closure that determines if
-    /// a character matches.
+    /// The [pattern] can be a `&str`, [`char`], a slice of [`char`]s, or a
+    /// function or closure that determines if a character matches.
+    ///
+    /// [`char`]: primitive.char.html
+    /// [pattern]: str/pattern/index.html
     ///
     /// # Iterator behavior
     ///
@@ -3634,8 +3684,11 @@ impl str {
     /// For matches of `pat` within `self` that overlap, only the indices
     /// corresponding to the first match are returned.
     ///
-    /// The pattern can be a `&str`, [`char`], or a closure that determines
-    /// if a character matches.
+    /// The [pattern] can be a `&str`, [`char`], a slice of [`char`]s, or a
+    /// function or closure that determines if a character matches.
+    ///
+    /// [`char`]: primitive.char.html
+    /// [pattern]: str/pattern/index.html
     ///
     /// # Iterator behavior
     ///
@@ -3676,8 +3729,11 @@ impl str {
     /// For matches of `pat` within `self` that overlap, only the indices
     /// corresponding to the last match are returned.
     ///
-    /// The pattern can be a `&str`, [`char`], or a closure that determines if a
-    /// character matches.
+    /// The [pattern] can be a `&str`, [`char`], a slice of [`char`]s, or a
+    /// function or closure that determines if a character matches.
+    ///
+    /// [`char`]: primitive.char.html
+    /// [pattern]: str/pattern/index.html
     ///
     /// # Iterator behavior
     ///
@@ -3894,8 +3950,11 @@ impl str {
     /// Returns a string slice with all prefixes and suffixes that match a
     /// pattern repeatedly removed.
     ///
-    /// The pattern can be a [`char`] or a closure that determines if a
-    /// character matches.
+    /// The [pattern] can be a [`char`], a slice of [`char`]s, or a function
+    /// or closure that determines if a character matches.
+    ///
+    /// [`char`]: primitive.char.html
+    /// [pattern]: str/pattern/index.html
     ///
     /// # Examples
     ///
@@ -3939,8 +3998,11 @@ impl str {
     /// Returns a string slice with all prefixes that match a pattern
     /// repeatedly removed.
     ///
-    /// The pattern can be a `&str`, [`char`], or a closure that determines if
-    /// a character matches.
+    /// The [pattern] can be a `&str`, [`char`], a slice of [`char`]s, or a
+    /// function or closure that determines if a character matches.
+    ///
+    /// [`char`]: primitive.char.html
+    /// [pattern]: str/pattern/index.html
     ///
     /// # Text directionality
     ///
@@ -3981,6 +4043,12 @@ impl str {
     ///
     /// If the string does not start with `prefix`, `None` is returned.
     ///
+    /// The [pattern] can be a `&str`, [`char`], a slice of [`char`]s, or a
+    /// function or closure that determines if a character matches.
+    ///
+    /// [`char`]: primitive.char.html
+    /// [pattern]: str/pattern/index.html
+    ///
     /// # Examples
     ///
     /// ```
@@ -4005,6 +4073,12 @@ impl str {
     ///
     /// If the string does not end with `suffix`, `None` is returned.
     ///
+    /// The [pattern] can be a `&str`, [`char`], a slice of [`char`]s, or a
+    /// function or closure that determines if a character matches.
+    ///
+    /// [`char`]: primitive.char.html
+    /// [pattern]: str/pattern/index.html
+    ///
     /// # Examples
     ///
     /// ```
@@ -4027,8 +4101,11 @@ impl str {
     /// Returns a string slice with all suffixes that match a pattern
     /// repeatedly removed.
     ///
-    /// The pattern can be a `&str`, [`char`], or a closure that
-    /// determines if a character matches.
+    /// The [pattern] can be a `&str`, [`char`], a slice of [`char`]s, or a
+    /// function or closure that determines if a character matches.
+    ///
+    /// [`char`]: primitive.char.html
+    /// [pattern]: str/pattern/index.html
     ///
     /// # Text directionality
     ///
@@ -4073,10 +4150,11 @@ impl str {
     /// Returns a string slice with all prefixes that match a pattern
     /// repeatedly removed.
     ///
-    /// The pattern can be a `&str`, [`char`], or a closure that determines if
-    /// a character matches.
+    /// The [pattern] can be a `&str`, [`char`], a slice of [`char`]s, or a
+    /// function or closure that determines if a character matches.
     ///
     /// [`char`]: primitive.char.html
+    /// [pattern]: str/pattern/index.html
     ///
     /// # Text directionality
     ///
@@ -4109,10 +4187,11 @@ impl str {
     /// Returns a string slice with all suffixes that match a pattern
     /// repeatedly removed.
     ///
-    /// The pattern can be a `&str`, [`char`], or a closure that
-    /// determines if a character matches.
+    /// The [pattern] can be a `&str`, [`char`], a slice of [`char`]s, or a
+    /// function or closure that determines if a character matches.
     ///
     /// [`char`]: primitive.char.html
+    /// [pattern]: str/pattern/index.html
     ///
     /// # Text directionality
     ///

src/libcore/str/pattern.rs

@@ -1,7 +1,41 @@
 //! The string Pattern API.
 //!
+//! The Pattern API provides a generic mechanism for using different pattern
+//! types when searching through a string.
+//!
 //! For more details, see the traits [`Pattern`], [`Searcher`],
 //! [`ReverseSearcher`], and [`DoubleEndedSearcher`].
+//!
+//! Although this API is unstable, it is exposed via stable APIs on the
+//! [`str`] type.
+//!
+//! # Examples
+//!
+//! [`Pattern`] is [implemented][pattern-impls] in the stable API for
+//! [`&str`], [`char`], slices of [`char`], and functions and closures
+//! implementing `FnMut(char) -> bool`.
+//!
+//! ```
+//! let s = "Can you find a needle in a haystack?";
+//!
+//! // &str pattern
+//! assert_eq!(s.find("you"), Some(4));
+//! // char pattern
+//! assert_eq!(s.find('n'), Some(2));
+//! // slice of chars pattern
+//! assert_eq!(s.find(&['a', 'e', 'i', 'o', 'u'][..]), Some(1));
+//! // closure pattern
+//! assert_eq!(s.find(|c: char| c.is_ascii_punctuation()), Some(35));
+//! ```
+//!
+//! [`&str`]: ../../../std/primitive.str.html
+//! [`char`]: ../../../std/primitive.char.html
+//! [`str`]: ../../../std/primitive.str.html
+//! [`DoubleEndedSearcher`]: trait.DoubleEndedSearcher.html
+//! [`Pattern`]: trait.Pattern.html
+//! [`ReverseSearcher`]: trait.ReverseSearcher.html
+//! [`Searcher`]: trait.Searcher.html
+//! [pattern-impls]: trait.Pattern.html#implementors
 
 #![unstable(
     feature = "pattern",
@@ -702,7 +736,7 @@ unsafe impl<'a, 'b> ReverseSearcher<'a> for CharSliceSearcher<'a, 'b> {
 
 impl<'a, 'b> DoubleEndedSearcher<'a> for CharSliceSearcher<'a, 'b> {}
 
-/// Searches for chars that are equal to any of the chars in the array.
+/// Searches for chars that are equal to any of the chars in the slice.
 ///
 /// # Examples
 ///

src/librustc_parse/parser/expr.rs

@@ -547,8 +547,7 @@ impl<'a> Parser<'a> {
                 // Rewind to before attempting to parse the type with generics, to recover
                 // from situations like `x as usize < y` in which we first tried to parse
                 // `usize < y` as a type with generic arguments.
-                let parser_snapshot_after_type = self.clone();
-                mem::replace(self, parser_snapshot_before_type);
+                let parser_snapshot_after_type = mem::replace(self, parser_snapshot_before_type);
 
                 match self.parse_path(PathStyle::Expr) {
                     Ok(path) => {
@@ -560,7 +559,7 @@ impl<'a> Parser<'a> {
                                 // example because `parse_ty_no_plus` returns `Err` on keywords,
                                 // but `parse_path` returns `Ok` on them due to error recovery.
                                 // Return original error and parser state.
-                                mem::replace(self, parser_snapshot_after_type);
+                                *self = parser_snapshot_after_type;
                                 return Err(type_err);
                             }
                         };
@@ -601,7 +600,7 @@ impl<'a> Parser<'a> {
                     Err(mut path_err) => {
                         // Couldn't parse as a path, return original error and parser state.
                         path_err.cancel();
-                        mem::replace(self, parser_snapshot_after_type);
+                        *self = parser_snapshot_after_type;
                         return Err(type_err);
                     }
                 }

src/librustc_parse/parser/generics.rs

@@ -105,7 +105,7 @@ impl<'a> Parser<'a> {
                     }
                     Err(mut err) => {
                         err.cancel();
-                        std::mem::replace(self, snapshot);
+                        *self = snapshot;
                         break;
                     }
                 }

src/librustc_parse/parser/item.rs

@@ -1650,7 +1650,7 @@ impl<'a> Parser<'a> {
                 // Recover from attempting to parse the argument as a type without pattern.
                 Err(mut err) => {
                     err.cancel();
-                    mem::replace(self, parser_snapshot_before_ty);
+                    *self = parser_snapshot_before_ty;
                     self.recover_arg_parse()?
                 }
             }

src/librustc_parse/parser/stmt.rs

@@ -163,8 +163,8 @@ impl<'a> Parser<'a> {
                 Ok(ty) => (None, Some(ty)),
                 Err(mut err) => {
                     // Rewind to before attempting to parse the type and continue parsing.
-                    let parser_snapshot_after_type = self.clone();
-                    mem::replace(self, parser_snapshot_before_type);
+                    let parser_snapshot_after_type =
+                        mem::replace(self, parser_snapshot_before_type);
                     if let Ok(snip) = self.span_to_snippet(pat.span) {
                         err.span_label(pat.span, format!("while parsing the type for `{}`", snip));
                     }
@@ -201,7 +201,7 @@ impl<'a> Parser<'a> {
                 // Couldn't parse the type nor the initializer, only raise the type error and
                 // return to the parser state before parsing the type as the initializer.
                 // let x: <parse_error>;
-                mem::replace(self, snapshot);
+                *self = snapshot;
                 return Err(ty_err);
             }
             (Err(err), None) => {

src/librustc_resolve/late/lifetimes.rs

@@ -26,7 +26,7 @@ use rustc_span::symbol::{kw, sym};
 use rustc_span::Span;
 use std::borrow::Cow;
 use std::cell::Cell;
-use std::mem::{replace, take};
+use std::mem::take;
 
 use log::debug;
 
@@ -371,7 +371,7 @@ impl<'a, 'tcx> Visitor<'tcx> for LifetimeContext<'a, 'tcx> {
         self.with(Scope::Body { id: body.id(), s: self.scope }, |_, this| {
             this.visit_body(body);
         });
-        replace(&mut self.labels_in_fn, saved);
+        self.labels_in_fn = saved;
     }
 
     fn visit_item(&mut self, item: &'tcx hir::Item<'tcx>) {

src/librustdoc/html/render.rs

@@ -789,6 +789,37 @@ themePicker.onblur = handleThemeButtonsBlur;
         Ok((ret, krates))
     }
 
+    fn collect_json(path: &Path, krate: &str) -> io::Result<(Vec<String>, Vec<String>)> {
+        let mut ret = Vec::new();
+        let mut krates = Vec::new();
+
+        if path.exists() {
+            for line in BufReader::new(File::open(path)?).lines() {
+                let line = line?;
+                if !line.starts_with("\"") {
+                    continue;
+                }
+                if line.starts_with(&format!("\"{}\"", krate)) {
+                    continue;
+                }
+                if line.ends_with(",\\") {
+                    ret.push(line[..line.len() - 2].to_string());
+                } else {
+                    // Ends with "\\" (it's the case for the last added crate line)
+                    ret.push(line[..line.len() - 1].to_string());
+                }
+                krates.push(
+                    line.split('"')
+                        .filter(|s| !s.is_empty())
+                        .next()
+                        .map(|s| s.to_owned())
+                        .unwrap_or_else(String::new),
+                );
+            }
+        }
+        Ok((ret, krates))
+    }
+
     fn show_item(item: &IndexItem, krate: &str) -> String {
         format!(
             "{{'crate':'{}','ty':{},'name':'{}','desc':'{}','p':'{}'{}}}",
@@ -909,18 +940,18 @@ themePicker.onblur = handleThemeButtonsBlur;
 
     // Update the search index
     let dst = cx.dst.join(&format!("search-index{}.js", cx.shared.resource_suffix));
-    let (mut all_indexes, mut krates) = try_err!(collect(&dst, &krate.name, "searchIndex"), &dst);
+    let (mut all_indexes, mut krates) = try_err!(collect_json(&dst, &krate.name), &dst);
     all_indexes.push(search_index);
 
     // Sort the indexes by crate so the file will be generated identically even
     // with rustdoc running in parallel.
     all_indexes.sort();
     {
-        let mut v = String::from("var searchIndex={};\n");
-        v.push_str(&all_indexes.join("\n"));
+        let mut v = String::from("var searchIndex = JSON.parse('{\\\n");
+        v.push_str(&all_indexes.join(",\\\n"));
         // "addSearchOptions" has to be called first so the crate filtering can be set before the
         // search might start (if it's set into the URL for example).
-        v.push_str("\naddSearchOptions(searchIndex);initSearch(searchIndex);");
+        v.push_str("\\\n}');\naddSearchOptions(searchIndex);initSearch(searchIndex);");
         cx.shared.fs.write(&dst, &v)?;
     }
     if options.enable_index_page {

src/librustdoc/html/render/cache.rs

@@ -634,14 +634,19 @@ fn build_index(krate: &clean::Crate, cache: &mut Cache) -> String {
 
     // Collect the index into a string
     format!(
-        r#"searchIndex["{}"] = {};"#,
+        r#""{}":{}"#,
         krate.name,
         serde_json::to_string(&CrateData {
             doc: crate_doc,
             items: crate_items,
             paths: crate_paths,
         })
         .expect("failed serde conversion")
+        // All these `replace` calls are because we have to go through JS string for JSON content.
+        .replace(r"\", r"\\")
+        .replace("'", r"\'")
+        // We need to escape double quotes for the JSON.
+        .replace("\\\"", "\\\\\"")
     )
 }
 

src/libstd/path.rs

@@ -1116,7 +1116,6 @@ impl PathBuf {
     /// # Examples
     ///
     /// ```
-    /// #![feature(path_buf_capacity)]
     /// use std::path::PathBuf;
     ///
     /// let mut path = PathBuf::with_capacity(10);
@@ -1130,7 +1129,7 @@ impl PathBuf {
     ///
     /// [`with_capacity`]: ../ffi/struct.OsString.html#method.with_capacity
     /// [`OsString`]: ../ffi/struct.OsString.html
-    #[unstable(feature = "path_buf_capacity", issue = "58234")]
+    #[stable(feature = "path_buf_capacity", since = "1.44.0")]
     pub fn with_capacity(capacity: usize) -> PathBuf {
         PathBuf { inner: OsString::with_capacity(capacity) }
     }
@@ -1374,7 +1373,7 @@ impl PathBuf {
     ///
     /// [`capacity`]: ../ffi/struct.OsString.html#method.capacity
     /// [`OsString`]: ../ffi/struct.OsString.html
-    #[unstable(feature = "path_buf_capacity", issue = "58234")]
+    #[stable(feature = "path_buf_capacity", since = "1.44.0")]
     pub fn capacity(&self) -> usize {
         self.inner.capacity()
     }
@@ -1383,7 +1382,7 @@ impl PathBuf {
     ///
     /// [`clear`]: ../ffi/struct.OsString.html#method.clear
     /// [`OsString`]: ../ffi/struct.OsString.html
-    #[unstable(feature = "path_buf_capacity", issue = "58234")]
+    #[stable(feature = "path_buf_capacity", since = "1.44.0")]
     pub fn clear(&mut self) {
         self.inner.clear()
     }
@@ -1392,7 +1391,7 @@ impl PathBuf {
     ///
     /// [`reserve`]: ../ffi/struct.OsString.html#method.reserve
     /// [`OsString`]: ../ffi/struct.OsString.html
-    #[unstable(feature = "path_buf_capacity", issue = "58234")]
+    #[stable(feature = "path_buf_capacity", since = "1.44.0")]
     pub fn reserve(&mut self, additional: usize) {
         self.inner.reserve(additional)
     }
@@ -1401,7 +1400,7 @@ impl PathBuf {
     ///
     /// [`reserve_exact`]: ../ffi/struct.OsString.html#method.reserve_exact
     /// [`OsString`]: ../ffi/struct.OsString.html
-    #[unstable(feature = "path_buf_capacity", issue = "58234")]
+    #[stable(feature = "path_buf_capacity", since = "1.44.0")]
     pub fn reserve_exact(&mut self, additional: usize) {
         self.inner.reserve_exact(additional)
     }
@@ -1410,7 +1409,7 @@ impl PathBuf {
     ///
     /// [`shrink_to_fit`]: ../ffi/struct.OsString.html#method.shrink_to_fit
     /// [`OsString`]: ../ffi/struct.OsString.html
-    #[unstable(feature = "path_buf_capacity", issue = "58234")]
+    #[stable(feature = "path_buf_capacity", since = "1.44.0")]
     pub fn shrink_to_fit(&mut self) {
         self.inner.shrink_to_fit()
     }
@@ -1419,7 +1418,7 @@ impl PathBuf {
     ///
     /// [`shrink_to`]: ../ffi/struct.OsString.html#method.shrink_to
     /// [`OsString`]: ../ffi/struct.OsString.html
-    #[unstable(feature = "path_buf_capacity", issue = "58234")]
+    #[unstable(feature = "shrink_to", issue = "56431")]
     pub fn shrink_to(&mut self, min_capacity: usize) {
         self.inner.shrink_to(min_capacity)
     }

src/libstd/thread/local.rs

@@ -301,7 +301,7 @@ mod lazy {
             // value (an aliasing violation). To avoid setting the "I'm running a
             // destructor" flag we just use `mem::replace` which should sequence the
             // operations a little differently and make this safe to call.
-            mem::replace(&mut *ptr, Some(value));
+            let _ = mem::replace(&mut *ptr, Some(value));
 
             // After storing `Some` we want to get a reference to the contents of
             // what we just stored. While we could use `unwrap` here and it should

src/test/ui/imports/import-in-block.rs

@@ -4,7 +4,7 @@
 pub fn main() {
     use std::mem::replace;
     let mut x = 5;
-    replace(&mut x, 6);
+    let _ = replace(&mut x, 6);
     {
         use std::mem::*;
         let mut y = 6;

src/test/ui/issues/issue-23611-enum-swap-in-drop.rs

@@ -153,6 +153,7 @@ impl<'a> Drop for E<'a> {
             }
         };
 
+        #[allow(unused_must_use)]
         if do_drop {
             mem::replace(self, E::A(GaspA(f_a, 0xA3A0, log, D::new("drop", 6, log)), true));
         }