std_unicode: impl Clone for .split_whitespace()

Use custom closure structs for the predicates so that the iterator's
clone can simply be derived. This should also reduce virtual call
overhead by not using function pointers.

1 files changed, 2 insertions, 0 deletions

diff --git a/src/libstd_unicode/lib.rs b/src/libstd_unicode/lib.rs
index 7e5ab1a54ab..d63878a7a7c 100644
--- a/src/libstd_unicode/lib.rs
+++ b/src/libstd_unicode/lib.rs
@@ -36,9 +36,11 @@
 #![feature(core_char_ext)]
 #![feature(decode_utf8)]
 #![feature(fused)]
+#![feature(fn_traits)]
 #![feature(lang_items)]
 #![feature(staged_api)]
 #![feature(try_from)]
+#![feature(unboxed_closures)]
 
 mod tables;
 mod u_str;