Add specialization of `ToString for char`

[rust.git] / src / liballoc / string.rs

diff --git a/src/liballoc/string.rs b/src/liballoc/string.rs
index f3fe1adebb141d4dd3c1b91b2c42e304825e3112..fa5757a0b11380515132401b732043111f868732 100644 (file)
--- a/src/liballoc/string.rs
+++ b/src/liballoc/string.rs
@@ -1799,6 +1799,16 @@ fn extend<I: IntoIterator<Item = char>>(&mut self, iter: I) {
         self.reserve(lower_bound);
         iterator.for_each(move |c| self.push(c));
     }
+
+    #[inline]
+    fn extend_one(&mut self, c: char) {
+        self.push(c);
+    }
+
+    #[inline]
+    fn extend_reserve(&mut self, additional: usize) {
+        self.reserve(additional);
+    }
 }
 
 #[stable(feature = "extend_ref", since = "1.2.0")]
@@ -1806,6 +1816,16 @@ impl<'a> Extend<&'a char> for String {
     fn extend<I: IntoIterator<Item = &'a char>>(&mut self, iter: I) {
         self.extend(iter.into_iter().cloned());
     }
+
+    #[inline]
+    fn extend_one(&mut self, &c: &'a char) {
+        self.push(c);
+    }
+
+    #[inline]
+    fn extend_reserve(&mut self, additional: usize) {
+        self.reserve(additional);
+    }
 }
 
 #[stable(feature = "rust1", since = "1.0.0")]
@@ -1813,6 +1833,11 @@ impl<'a> Extend<&'a str> for String {
     fn extend<I: IntoIterator<Item = &'a str>>(&mut self, iter: I) {
         iter.into_iter().for_each(move |s| self.push_str(s));
     }
+
+    #[inline]
+    fn extend_one(&mut self, s: &'a str) {
+        self.push_str(s);
+    }
 }
 
 #[stable(feature = "extend_string", since = "1.4.0")]
@@ -1820,6 +1845,11 @@ impl Extend<String> for String {
     fn extend<I: IntoIterator<Item = String>>(&mut self, iter: I) {
         iter.into_iter().for_each(move |s| self.push_str(&s));
     }
+
+    #[inline]
+    fn extend_one(&mut self, s: String) {
+        self.push_str(&s);
+    }
 }
 
 #[stable(feature = "herd_cows", since = "1.19.0")]
@@ -1827,6 +1857,11 @@ impl<'a> Extend<Cow<'a, str>> for String {
     fn extend<I: IntoIterator<Item = Cow<'a, str>>>(&mut self, iter: I) {
         iter.into_iter().for_each(move |s| self.push_str(&s));
     }
+
+    #[inline]
+    fn extend_one(&mut self, s: Cow<'a, str>) {
+        self.push_str(&s);
+    }
 }
 
 /// A convenience impl that delegates to the impl for `&str`.
@@ -2193,6 +2228,14 @@ impl<T: fmt::Display + ?Sized> ToString for T {
     }
 }
 
+#[stable(feature = "char_to_string_specialization", since = "1.46.0")]
+impl ToString for char {
+    #[inline]
+    fn to_string(&self) -> String {
+        String::from(self.encode_utf8(&mut [0; 4]))
+    }
+}
+
 #[stable(feature = "str_to_string_specialization", since = "1.9.0")]
 impl ToString for str {
     #[inline]