40 -> 39, as ceil(log10(2^128)) == 39

just as ceil(log10(2^64)) == 20

1 files changed, 1 insertions, 1 deletions

diff --git a/src/libcore/fmt/num.rs b/src/libcore/fmt/num.rs
index 7b6c2d48889..cd725392b66 100644
--- a/src/libcore/fmt/num.rs
+++ b/src/libcore/fmt/num.rs
@@ -211,7 +211,7 @@ macro_rules! impl_Display {
                 // convert the negative num to positive by summing 1 to it's 2 complement
                 (!self.$conv_fn()).wrapping_add(1)
             };
-            let mut buf: [u8; 40] = unsafe { mem::uninitialized() };
+            let mut buf: [u8; 39] = unsafe { mem::uninitialized() };
             let mut curr = buf.len() as isize;
             let buf_ptr = buf.as_mut_ptr();
             let lut_ptr = DEC_DIGITS_LUT.as_ptr();