  use num::flt2dec;
  use ops::Deref;
  use result;
-@@ -985,6 +654,7 @@ impl<'a> Formatter<'a> {
+@@ -991,6 +654,7 @@ impl<'a> Formatter<'a> {
      /// Takes the formatted parts and applies the padding.
      /// Assumes that the caller already has rendered the parts with required precision,
      /// so that `self.precision` can be ignored.

     fn write_formatted_parts(&mut self, formatted: &flt2dec::Formatted) -> Result {
         fn write_bytes(buf: &mut Write, s: &[u8]) -> Result {
             buf.write_str(unsafe { str::from_utf8_unchecked(s) })
@@ -1386,6 +1057,7 @@ impl<'a, T> Pointer for &'a mut T {
     }
 }
 

diff -ru libcore/lib.rs libcore_patched/lib.rs
--- libcore/lib.rs	2015-07-02 13:02:27.899621472 +0800
+++ libcore_patched/lib.rs	2015-07-02 13:02:04.780163524 +0800
@@ -114,7 +110,9 @@
 #[path = "num/u32.rs"]  pub mod u32;
 #[path = "num/u64.rs"]  pub mod u64;
 
