Use vec![elt; n] where possible

The common pattern `iter::repeat(elt).take(n).collect::<Vec<_>>()` is
exactly equivalent to `vec![elt; n]`, do this replacement in the whole
tree.

(Actually, vec![] is smart enough to only call clone n - 1 times, while
the former solution would call clone n times, and this fact is
virtually irrelevant in practice.)

1 files changed, 1 insertions, 2 deletions

diff --git a/src/libsyntax/ext/format.rs b/src/libsyntax/ext/format.rs
index 86e72d4ef03..5b972b464c9 100644
--- a/src/libsyntax/ext/format.rs
+++ b/src/libsyntax/ext/format.rs
@@ -23,7 +23,6 @@ use parse::token;
 use ptr::P;
 
 use std::collections::HashMap;
-use std::iter::repeat;
 
 #[derive(PartialEq)]
 enum ArgumentType {
@@ -469,7 +468,7 @@ impl<'a, 'b> Context<'a, 'b> {
     /// to
     fn into_expr(mut self) -> P<ast::Expr> {
         let mut locals = Vec::new();
-        let mut names: Vec<_> = repeat(None).take(self.name_positions.len()).collect();
+        let mut names = vec![None; self.name_positions.len()];
         let mut pats = Vec::new();
         let mut heads = Vec::new();