Make push_str overallocate. Use it in some places that were still doing +=.

1 files changed, 1 insertions, 1 deletions

diff --git a/src/libstd/sha1.rs b/src/libstd/sha1.rs
index 607388bd559..dc136af639a 100644
--- a/src/libstd/sha1.rs
+++ b/src/libstd/sha1.rs
@@ -265,7 +265,7 @@ mod tests {
         fn a_million_letter_a() -> str {
             let mut i = 0;
             let mut rs = "";
-            while i < 100000 { rs += "aaaaaaaaaa"; i += 1; }
+            while i < 100000 { str::push_str(rs, "aaaaaaaaaa"); i += 1; }
             ret rs;
         }
         // Test messages from FIPS 180-1