auto merge of #15493 : brson/rust/tostr, r=pcwalton

This updates https://github.com/rust-lang/rust/pull/15075.

Rename `ToStr::to_str` to `ToString::to_string`. The naive renaming ends up with two `to_string` functions defined on strings in the prelude (the other defined via `collections::str::StrAllocating`). To remedy this I removed `StrAllocating::to_string`, making all conversions from `&str` to `String` go through `Show`. This has a measurable impact on the speed of this conversion, but the sense I get from others is that it's best to go ahead and unify `to_string` and address performance for all `to_string` conversions in `core::fmt`. `String::from_str(...)` still works as a manual fast-path.

Note that the patch was done with a script, and ended up renaming a number of other `*_to_str` functions, particularly inside of rustc. All the ones I saw looked correct, and I didn't notice any additional API breakage.

Closes #15046.

3 files changed, 8 insertions, 7 deletions

diff --git a/src/libnum/bigint.rs b/src/libnum/bigint.rs
index cc3753def59..046ba96f45a 100644
--- a/src/libnum/bigint.rs
+++ b/src/libnum/bigint.rs
@@ -2737,7 +2737,7 @@ mod bigint_tests {
         // attempt to allocate a vector of size (-1u) == huge.
         let x: BigInt =
             from_str(format!("1{}", "0".repeat(36)).as_slice()).unwrap();
-        let _y = x.to_str();
+        let _y = x.to_string();
     }
 
     #[test]
@@ -2842,14 +2842,14 @@ mod bench {
     }
 
     #[bench]
-    fn to_str(b: &mut Bencher) {
+    fn to_string(b: &mut Bencher) {
         let fac = factorial(100);
         let fib = fib(100);
         b.iter(|| {
-            fac.to_str();
+            fac.to_string();
         });
         b.iter(|| {
-            fib.to_str();
+            fib.to_string();
         });
     }
 
diff --git a/src/libnum/complex.rs b/src/libnum/complex.rs
index 9ee80d283cf..f4a3ac97a4e 100644
--- a/src/libnum/complex.rs
+++ b/src/libnum/complex.rs
@@ -347,9 +347,9 @@ mod test {
     }
 
     #[test]
-    fn test_to_str() {
+    fn test_to_string() {
         fn test(c : Complex64, s: String) {
-            assert_eq!(c.to_str(), s);
+            assert_eq!(c.to_string(), s);
         }
         test(_0_0i, "0+0i".to_string());
         test(_1_0i, "1+0i".to_string());
diff --git a/src/libnum/rational.rs b/src/libnum/rational.rs
index 1792f282eca..a279ede6fa5 100644
--- a/src/libnum/rational.rs
+++ b/src/libnum/rational.rs
@@ -17,6 +17,7 @@ use std::fmt;
 use std::from_str::FromStr;
 use std::num;
 use std::num::{Zero, One, ToStrRadix, FromStrRadix};
+
 use bigint::{BigInt, BigUint, Sign, Plus, Minus};
 
 /// Represents the ratio between 2 numbers.
@@ -603,7 +604,7 @@ mod test {
     fn test_to_from_str() {
         fn test(r: Rational, s: String) {
             assert_eq!(FromStr::from_str(s.as_slice()), Some(r));
-            assert_eq!(r.to_str(), s);
+            assert_eq!(r.to_string(), s);
         }
         test(_1, "1".to_string());
         test(_0, "0".to_string());