Auto merge of #77997 - fusion-engineering-forks:to-string-no-shrink, r=joshtriplett

bors · bors · commit f1b97ee7f8ff · 2020-10-16T22:53:50.000Z
Remove shrink_to_fit from default ToString::to_string implementation.

As suggested by `@scottmcm` on Zulip. shrink_to_fit() seems like the wrong thing to do here in most use cases of to_string(). Would be intereseting to see if it makes any difference in a timer run.

r? `@joshtriplett`
diff --git a/library/alloc/src/string.rs b/library/alloc/src/string.rs
@@ -2200,7 +2200,6 @@ impl<T: fmt::Display + ?Sized> ToString for T {
         let mut buf = String::new();
         buf.write_fmt(format_args!("{}", self))
             .expect("a Display implementation returned an error unexpectedly");
-        buf.shrink_to_fit();
         buf
     }
 }

Original file line number	Diff line number	Diff line change
`@@ -2200,7 +2200,6 @@ impl<T: fmt::Display + ?Sized> ToString for T {`
`2200`	`2200`	`let mut buf = String::new();`
`2201`	`2201`	`buf.write_fmt(format_args!("{}", self))`
`2202`	`2202`	`.expect("a Display implementation returned an error unexpectedly");`
`2203`		`- buf.shrink_to_fit();`
`2204`	`2203`	`buf`
`2205`	`2204`	`}`
`2206`	`2205`	`}`