Rollup merge of #37574 - ollie27:cow_add, r=alexcrichton
Fix issues with the Add/AddAssign impls for Cow<str> * Correct the stability attributes. * Make Add and AddAssign actually behave the same. * Use String::with_capacity when allocating a new string. * Fix the tests.
This commit is contained in:
Alex Crichton
commit
638436e55f
@ -17,6 +17,7 @@ use core::hash::{Hash, Hasher};
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use core::ops::{Add, AddAssign, Deref};
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use fmt;
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use string::String;
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use self::Cow::*;
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@ -284,48 +285,60 @@ impl<'a, T: ?Sized + ToOwned> AsRef<T> for Cow<'a, T> {
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}
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}
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#[stable(feature = "cow_add", since = "1.13.0")]
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#[stable(feature = "cow_add", since = "1.14.0")]
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impl<'a> Add<&'a str> for Cow<'a, str> {
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type Output = Cow<'a, str>;
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fn add(self, rhs: &'a str) -> Self {
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if self == "" {
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Cow::Borrowed(rhs)
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} else if rhs == "" {
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self
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} else {
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Cow::Owned(self.into_owned() + rhs)
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}
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#[inline]
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fn add(mut self, rhs: &'a str) -> Self::Output {
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self += rhs;
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self
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}
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}
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#[stable(feature = "cow_add", since = "1.13.0")]
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#[stable(feature = "cow_add", since = "1.14.0")]
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impl<'a> Add<Cow<'a, str>> for Cow<'a, str> {
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type Output = Cow<'a, str>;
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fn add(self, rhs: Cow<'a, str>) -> Self {
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if self == "" {
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rhs
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} else if rhs == "" {
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self
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#[inline]
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fn add(mut self, rhs: Cow<'a, str>) -> Self::Output {
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self += rhs;
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self
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}
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}
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#[stable(feature = "cow_add", since = "1.14.0")]
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impl<'a> AddAssign<&'a str> for Cow<'a, str> {
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fn add_assign(&mut self, rhs: &'a str) {
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if self.is_empty() {
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*self = Cow::Borrowed(rhs)
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} else if rhs.is_empty() {
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return;
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} else {
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Cow::Owned(self.into_owned() + rhs.borrow())
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if let Cow::Borrowed(lhs) = *self {
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let mut s = String::with_capacity(lhs.len() + rhs.len());
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s.push_str(lhs);
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*self = Cow::Owned(s);
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}
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self.to_mut().push_str(rhs);
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}
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}
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}
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#[stable(feature = "cow_add", since = "1.13.0")]
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impl<'a> AddAssign<&'a str> for Cow<'a, str> {
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fn add_assign(&mut self, rhs: &'a str) {
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if rhs == "" { return; }
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self.to_mut().push_str(rhs);
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}
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}
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#[stable(feature = "cow_add", since = "1.13.0")]
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#[stable(feature = "cow_add", since = "1.14.0")]
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impl<'a> AddAssign<Cow<'a, str>> for Cow<'a, str> {
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fn add_assign(&mut self, rhs: Cow<'a, str>) {
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if rhs == "" { return; }
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self.to_mut().push_str(rhs.borrow());
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if self.is_empty() {
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*self = rhs
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} else if rhs.is_empty() {
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return;
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} else {
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if let Cow::Borrowed(lhs) = *self {
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let mut s = String::with_capacity(lhs.len() + rhs.len());
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s.push_str(lhs);
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*self = Cow::Owned(s);
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}
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self.to_mut().push_str(&rhs);
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}
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}
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}
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@ -1,4 +1,4 @@
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// Copyright 2012-2013-2014 The Rust Project Developers. See the COPYRIGHT
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// Copyright 2016 The Rust Project Developers. See the COPYRIGHT
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// file at the top-level directory of this distribution and at
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// http://rust-lang.org/COPYRIGHT.
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//
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@ -12,54 +12,130 @@ use std::borrow::Cow;
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// check that Cow<'a, str> implements addition
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#[test]
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fn check_cow_add() {
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borrowed1 = Cow::Borrowed("Hello, ");
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borrowed2 = Cow::Borrowed("World!");
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borrow_empty = Cow::Borrowed("");
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fn check_cow_add_cow() {
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let borrowed1 = Cow::Borrowed("Hello, ");
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let borrowed2 = Cow::Borrowed("World!");
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let borrow_empty = Cow::Borrowed("");
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owned1 = Cow::Owned("Hi, ".into());
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owned2 = Cow::Owned("Rustaceans!".into());
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owned_empty = Cow::Owned("".into());
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let owned1: Cow<str> = Cow::Owned(String::from("Hi, "));
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let owned2: Cow<str> = Cow::Owned(String::from("Rustaceans!"));
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let owned_empty: Cow<str> = Cow::Owned(String::new());
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assert_eq!("Hello, World!", borrowed1 + borrowed2);
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assert_eq!("Hello, Rustaceans!", borrowed1 + owned2);
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assert_eq!("Hello, World!", borrowed1.clone() + borrowed2.clone());
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assert_eq!("Hello, Rustaceans!", borrowed1.clone() + owned2.clone());
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assert_eq!("Hello, World!", owned1 + borrowed2);
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assert_eq!("Hello, Rustaceans!", owned1 + owned2);
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assert_eq!("Hi, World!", owned1.clone() + borrowed2.clone());
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assert_eq!("Hi, Rustaceans!", owned1.clone() + owned2.clone());
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if let Cow::Owned(_) = borrowed1 + borrow_empty {
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if let Cow::Owned(_) = borrowed1.clone() + borrow_empty.clone() {
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panic!("Adding empty strings to a borrow should note allocate");
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}
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if let Cow::Owned(_) = borrow_empty + borrowed1 {
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if let Cow::Owned(_) = borrow_empty.clone() + borrowed1.clone() {
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panic!("Adding empty strings to a borrow should note allocate");
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}
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if let Cow::Owned(_) = borrowed1 + owned_empty {
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if let Cow::Owned(_) = borrowed1.clone() + owned_empty.clone() {
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panic!("Adding empty strings to a borrow should note allocate");
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}
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if let Cow::Owned(_) = owned_empty + borrowed1 {
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if let Cow::Owned(_) = owned_empty.clone() + borrowed1.clone() {
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panic!("Adding empty strings to a borrow should note allocate");
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}
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}
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fn check_cow_add_assign() {
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borrowed1 = Cow::Borrowed("Hello, ");
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borrowed2 = Cow::Borrowed("World!");
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borrow_empty = Cow::Borrowed("");
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#[test]
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fn check_cow_add_str() {
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let borrowed = Cow::Borrowed("Hello, ");
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let borrow_empty = Cow::Borrowed("");
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owned1 = Cow::Owned("Hi, ".into());
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owned2 = Cow::Owned("Rustaceans!".into());
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owned_empty = Cow::Owned("".into());
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let owned: Cow<str> = Cow::Owned(String::from("Hi, "));
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let owned_empty: Cow<str> = Cow::Owned(String::new());
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let borrowed1clone = borrowed1.clone();
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borrowed1clone += borrow_empty;
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assert_eq!((&borrowed1clone).as_ptr(), (&borrowed1).as_ptr());
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assert_eq!("Hello, World!", borrowed.clone() + "World!");
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borrowed1clone += owned_empty;
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assert_eq!((&borrowed1clone).as_ptr(), (&borrowed1).as_ptr());
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assert_eq!("Hi, World!", owned.clone() + "World!");
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if let Cow::Owned(_) = borrowed.clone() + "" {
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panic!("Adding empty strings to a borrow should note allocate");
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}
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if let Cow::Owned(_) = borrow_empty.clone() + "Hello, " {
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panic!("Adding empty strings to a borrow should note allocate");
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}
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if let Cow::Owned(_) = owned_empty.clone() + "Hello, " {
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panic!("Adding empty strings to a borrow should note allocate");
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}
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}
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#[test]
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fn check_cow_add_assign_cow() {
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let mut borrowed1 = Cow::Borrowed("Hello, ");
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let borrowed2 = Cow::Borrowed("World!");
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let borrow_empty = Cow::Borrowed("");
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let mut owned1: Cow<str> = Cow::Owned(String::from("Hi, "));
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let owned2: Cow<str> = Cow::Owned(String::from("Rustaceans!"));
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let owned_empty: Cow<str> = Cow::Owned(String::new());
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let mut s = borrowed1.clone();
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s += borrow_empty.clone();
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assert_eq!("Hello, ", s);
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if let Cow::Owned(_) = s {
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panic!("Adding empty strings to a borrow should note allocate");
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}
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let mut s = borrow_empty.clone();
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s += borrowed1.clone();
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assert_eq!("Hello, ", s);
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if let Cow::Owned(_) = s {
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panic!("Adding empty strings to a borrow should note allocate");
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}
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let mut s = borrowed1.clone();
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s += owned_empty.clone();
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assert_eq!("Hello, ", s);
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if let Cow::Owned(_) = s {
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panic!("Adding empty strings to a borrow should note allocate");
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}
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let mut s = owned_empty.clone();
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s += borrowed1.clone();
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assert_eq!("Hello, ", s);
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if let Cow::Owned(_) = s {
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panic!("Adding empty strings to a borrow should note allocate");
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}
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owned1 += borrowed2;
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borrowed1 += owned2;
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assert_eq!("Hello, World!", owned1);
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assert_eq!("Hi, World!", owned1);
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assert_eq!("Hello, Rustaceans!", borrowed1);
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}
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#[test]
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fn check_cow_add_assign_str() {
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let mut borrowed = Cow::Borrowed("Hello, ");
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let borrow_empty = Cow::Borrowed("");
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let mut owned: Cow<str> = Cow::Owned(String::from("Hi, "));
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let owned_empty: Cow<str> = Cow::Owned(String::new());
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let mut s = borrowed.clone();
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s += "";
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assert_eq!("Hello, ", s);
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if let Cow::Owned(_) = s {
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panic!("Adding empty strings to a borrow should note allocate");
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}
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let mut s = borrow_empty.clone();
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s += "World!";
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assert_eq!("World!", s);
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if let Cow::Owned(_) = s {
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panic!("Adding empty strings to a borrow should note allocate");
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}
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let mut s = owned_empty.clone();
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s += "World!";
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assert_eq!("World!", s);
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if let Cow::Owned(_) = s {
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panic!("Adding empty strings to a borrow should note allocate");
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}
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owned += "World!";
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borrowed += "World!";
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assert_eq!("Hi, World!", owned);
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assert_eq!("Hello, World!", borrowed);
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}
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@ -42,6 +42,7 @@ mod bench;
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mod binary_heap;
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mod btree;
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mod cow_str;
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mod enum_set;
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mod fmt;
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mod linked_list;
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