Use str::repeat

src/libcore/tests/num/dec2flt/parse.rs

@@ -8,7 +8,6 @@
 // option. This file may not be copied, modified, or distributed
 // except according to those terms.
 
-use std::iter;
 use core::num::dec2flt::parse::{Decimal, parse_decimal};
 use core::num::dec2flt::parse::ParseResult::{Valid, Invalid};
 
@@ -46,7 +45,7 @@ fn valid() {
     assert_eq!(parse_decimal("1.e300"), Valid(Decimal::new(b"1", b"", 300)));
     assert_eq!(parse_decimal(".1e300"), Valid(Decimal::new(b"", b"1", 300)));
     assert_eq!(parse_decimal("101e-33"), Valid(Decimal::new(b"101", b"", -33)));
-    let zeros: String = iter::repeat('0').take(25).collect();
+    let zeros = "0".repeat(25);
     let s = format!("1.5e{}", zeros);
     assert_eq!(parse_decimal(&s), Valid(Decimal::new(b"1", b"5", 0)));
 }

src/librustc/util/common.rs

@@ -17,7 +17,6 @@ use std::collections::HashMap;
 use std::ffi::CString;
 use std::fmt::Debug;
 use std::hash::{Hash, BuildHasher};
-use std::iter::repeat;
 use std::panic;
 use std::env;
 use std::path::Path;
@@ -219,7 +218,7 @@ fn print_time_passes_entry_internal(what: &str, dur: Duration) {
         None => "".to_owned(),
     };
     println!("{}time: {}{}\t{}",
-             repeat("  ").take(indentation).collect::<String>(),
+             "  ".repeat(indentation),
              duration_to_secs_str(dur),
              mem_string,
              what);

src/librustc_driver/lib.rs

@@ -98,7 +98,6 @@ use std::error::Error;
 use std::ffi::OsString;
 use std::fmt::{self, Display};
 use std::io::{self, Read, Write};
-use std::iter::repeat;
 use std::mem;
 use std::panic;
 use std::path::{PathBuf, Path};
@@ -1253,9 +1252,7 @@ Available lint options:
                              .max()
                              .unwrap_or(0);
     let padded = |x: &str| {
-        let mut s = repeat(" ")
+        let mut s = " ".repeat(max_name_len - x.chars().count());
-                        .take(max_name_len - x.chars().count())
-                        .collect::<String>();
         s.push_str(x);
         s
     };
@@ -1287,9 +1284,7 @@ Available lint options:
                                         .unwrap_or(0));
 
     let padded = |x: &str| {
-        let mut s = repeat(" ")
+        let mut s = " ".repeat(max_name_len - x.chars().count());
-                        .take(max_name_len - x.chars().count())
-                        .collect::<String>();
         s.push_str(x);
         s
     };

src/librustc_errors/emitter.rs

@@ -901,9 +901,7 @@ impl EmitterWriter {
         //    |  |   length of label
         //    |  magic `3`
         //    `max_line_num_len`
-        let padding = (0..padding + label.len() + 5)
+        let padding = " ".repeat(padding + label.len() + 5);
-            .map(|_| " ")
-            .collect::<String>();
 
         /// Return whether `style`, or the override if present and the style is `NoStyle`.
         fn style_or_override(style: Style, override_style: Option<Style>) -> Style {

src/librustc_mir/hair/pattern/_match.rs

@@ -32,7 +32,7 @@ use arena::TypedArena;
 
 use std::cmp::{self, Ordering};
 use std::fmt;
-use std::iter::{FromIterator, IntoIterator, repeat};
+use std::iter::{FromIterator, IntoIterator};
 
 pub fn expand_pattern<'a, 'tcx>(cx: &MatchCheckCtxt<'a, 'tcx>, pat: Pattern<'tcx>)
                                 -> &'a Pattern<'tcx>
@@ -115,7 +115,7 @@ impl<'a, 'tcx> fmt::Debug for Matrix<'a, 'tcx> {
         }).collect();
 
         let total_width = column_widths.iter().cloned().sum::<usize>() + column_count * 3 + 1;
-        let br = repeat('+').take(total_width).collect::<String>();
+        let br = "+".repeat(total_width);
         write!(f, "{}\n", br)?;
         for row in pretty_printed_matrix {
             write!(f, "+")?;

src/librustdoc/html/format.rs

@@ -16,7 +16,6 @@
 //! them in the future to instead emit any format desired.
 
 use std::fmt;
-use std::iter::repeat;
 
 use rustc::hir::def_id::DefId;
 use rustc_target::spec::abi::Abi;
@@ -235,10 +234,9 @@ impl<'a> fmt::Display for WhereClause<'a> {
 
         if !f.alternate() {
             clause.push_str("</span>");
-            let padding = repeat("&nbsp;").take(indent + 4).collect::<String>();
+            let padding = "&nbsp;".repeat(indent + 4);
             clause = clause.replace("<br>", &format!("<br>{}", padding));
-            clause.insert_str(0, &repeat("&nbsp;").take(indent.saturating_sub(1))
+            clause.insert_str(0, &"&nbsp;".repeat(indent.saturating_sub(1)));
-                                                  .collect::<String>());
             if !end_newline {
                 clause.insert_str(0, "<br>");
             }
@@ -409,13 +407,13 @@ pub fn href(did: DefId) -> Option<(String, ItemType, Vec<String>)> {
     let loc = CURRENT_LOCATION_KEY.with(|l| l.borrow().clone());
     let (fqp, shortty, mut url) = match cache.paths.get(&did) {
         Some(&(ref fqp, shortty)) => {
-            (fqp, shortty, repeat("../").take(loc.len()).collect())
+            (fqp, shortty, "../".repeat(loc.len()))
         }
         None => {
             let &(ref fqp, shortty) = cache.external_paths.get(&did)?;
             (fqp, shortty, match cache.extern_locations[&did.krate] {
                 (.., render::Remote(ref s)) => s.to_string(),
-                (.., render::Local) => repeat("../").take(loc.len()).collect(),
+                (.., render::Local) => "../".repeat(loc.len()),
                 (.., render::Unknown) => return None,
             })
         }
@@ -481,7 +479,7 @@ fn primitive_link(f: &mut fmt::Formatter,
                 let len = CURRENT_LOCATION_KEY.with(|s| s.borrow().len());
                 let len = if len == 0 {0} else {len - 1};
                 write!(f, "<a class=\"primitive\" href=\"{}primitive.{}.html\">",
-                       repeat("../").take(len).collect::<String>(),
+                       "../".repeat(len),
                        prim.to_url_str())?;
                 needs_termination = true;
             }
@@ -492,7 +490,7 @@ fn primitive_link(f: &mut fmt::Formatter,
                     }
                     (ref cname, _, render::Local) => {
                         let len = CURRENT_LOCATION_KEY.with(|s| s.borrow().len());
-                        Some((cname, repeat("../").take(len).collect::<String>()))
+                        Some((cname, "../".repeat(len)))
                     }
                     (.., render::Unknown) => None,
                 };
@@ -903,15 +901,15 @@ impl<'a> fmt::Display for Method<'a> {
             format!("{}", decl.output)
         };
 
-        let pad = repeat(" ").take(name_len).collect::<String>();
+        let pad = " ".repeat(name_len);
         let plain = format!("{pad}({args}){arrow}",
                         pad = pad,
                         args = args_plain,
                         arrow = arrow_plain);
 
         let output = if plain.len() > 80 {
-            let full_pad = format!("<br>{}", repeat("&nbsp;").take(indent + 4).collect::<String>());
+            let full_pad = format!("<br>{}", "&nbsp;".repeat(indent + 4));
-            let close_pad = format!("<br>{}", repeat("&nbsp;").take(indent).collect::<String>());
+            let close_pad = format!("<br>{}", "&nbsp;".repeat(indent));
             format!("({args}{close}){arrow}",
                     args = args.replace("<br>", &full_pad),
                     close = close_pad,

src/librustdoc/html/render.rs

@@ -46,7 +46,6 @@ use std::ffi::OsStr;
 use std::fs::{self, File, OpenOptions};
 use std::io::prelude::*;
 use std::io::{self, BufWriter, BufReader};
-use std::iter::repeat;
 use std::mem;
 use std::path::{PathBuf, Path, Component};
 use std::str;
@@ -1712,7 +1711,7 @@ impl Context {
     /// String representation of how to get back to the root path of the 'doc/'
     /// folder in terms of a relative URL.
     fn root_path(&self) -> String {
-        repeat("../").take(self.current.len()).collect::<String>()
+        "../".repeat(self.current.len())
     }
 
     /// Recurse in the directory structure and change the "root path" to make
@@ -2113,8 +2112,7 @@ impl<'a> fmt::Display for Item<'a> {
             let amt = if self.item.is_mod() { cur.len() - 1 } else { cur.len() };
             for (i, component) in cur.iter().enumerate().take(amt) {
                 write!(fmt, "<a href='{}index.html'>{}</a>::<wbr>",
-                       repeat("../").take(cur.len() - i - 1)
+                       "../".repeat(cur.len() - i - 1),
-                                    .collect::<String>(),
                        component)?;
             }
         }

src/libstd/tests/env.rs

@@ -11,7 +11,6 @@
 extern crate rand;
 
 use std::env::*;
-use std::iter::repeat;
 use std::ffi::{OsString, OsStr};
 
 use rand::Rng;
@@ -72,7 +71,7 @@ fn test_var_big() {
 #[cfg_attr(target_os = "emscripten", ignore)]
 fn test_env_set_get_huge() {
     let n = make_rand_name();
-    let s = repeat("x").take(10000).collect::<String>();
+    let s = "x".repeat(10000);
     set_var(&n, &s);
     eq(var_os(&n), Some(&s));
     remove_var(&n);

src/libsyntax/print/pprust.rs

@@ -32,7 +32,7 @@ use tokenstream::{self, TokenStream, TokenTree};
 
 use std::ascii;
 use std::io::{self, Write, Read};
-use std::iter::{self, Peekable};
+use std::iter::Peekable;
 use std::vec;
 
 pub enum AnnNode<'a> {
@@ -235,11 +235,11 @@ pub fn token_to_string(tok: &Token) -> String {
                 token::Integer(c)        => c.to_string(),
                 token::Str_(s)           => format!("\"{}\"", s),
                 token::StrRaw(s, n)      => format!("r{delim}\"{string}\"{delim}",
-                                                    delim=repeat("#", n as usize),
+                                                    delim="#".repeat(n as usize),
                                                     string=s),
                 token::ByteStr(v)         => format!("b\"{}\"", v),
                 token::ByteStrRaw(s, n)   => format!("br{delim}\"{string}\"{delim}",
-                                                    delim=repeat("#", n as usize),
+                                                    delim="#".repeat(n as usize),
                                                     string=s),
             };
 
@@ -661,7 +661,7 @@ pub trait PrintState<'a> {
             }
             ast::StrStyle::Raw(n) => {
                 (format!("r{delim}\"{string}\"{delim}",
-                         delim=repeat("#", n as usize),
+                         delim="#".repeat(n as usize),
                          string=st))
             }
         };
@@ -3180,8 +3180,6 @@ impl<'a> State<'a> {
     }
 }
 
-fn repeat(s: &str, n: usize) -> String { iter::repeat(s).take(n).collect() }
-
 #[cfg(test)]
 mod tests {
     use super::*;

src/libtest/lib.rs

@@ -66,7 +66,6 @@ use std::fmt;
 use std::fs::File;
 use std::io::prelude::*;
 use std::io;
-use std::iter::repeat;
 use std::path::PathBuf;
 use std::process::Termination;
 use std::sync::mpsc::{channel, Sender};
@@ -145,7 +144,7 @@ impl TestDesc {
     fn padded_name(&self, column_count: usize, align: NamePadding) -> String {
         let mut name = String::from(self.name.as_slice());
         let fill = column_count.saturating_sub(name.len());
-        let pad = repeat(" ").take(fill).collect::<String>();
+        let pad = " ".repeat(fill);
         match align {
             PadNone => name,
             PadOnRight => {