Fix no_std Bugs (#[serde(rename=int|bool)])

Author: Phaiax

serde/src/export.rs

@@ -14,9 +14,7 @@ pub use lib::marker::PhantomData;
 pub use lib::option::Option::{self, None, Some};
 pub use lib::result::Result::{self, Ok, Err};
 
-pub use self::string::from_utf8_lossy;
-pub use self::string::from_int;
-pub use self::string::from_bool;
+pub use self::string::{from_utf8_lossy, from_int, from_bool};
 
 mod string {
     use lib::*;
@@ -55,9 +53,11 @@ mod string {
 
     #[cfg(not(any(feature = "std", feature = "alloc")))]
     pub fn from_int(i: u64) -> [u8; 20] {
-        let buf = [0; 20];
-        let wrap = Wrapper { buf: &buf };
-        write!(wrap, "{}", i);
+        // len(str(1<<64)) = 20
+        let mut buf = [0; 20];
+        let wrap = Wrapper { buf: &mut buf };
+        use fmt::Write;
+        write!(wrap, "{}", i).ok();
         buf
     }