diff --git a/src/chains.rs b/src/chains.rs
index d798981415e8..6c3b6d1033dd 100644
--- a/src/chains.rs
+++ b/src/chains.rs
@@ -104,7 +104,7 @@ pub fn rewrite_chain(expr: &ast::Expr, context: &RewriteContext, shape: Shape) -
     };
     let parent_rewrite = parent
         .rewrite(context, parent_shape)
-        .map(|parent_rw| parent_rw + &repeat_try(prefix_try_num))?;
+        .map(|parent_rw| parent_rw + &"?".repeat(prefix_try_num))?;
     let parent_rewrite_contains_newline = parent_rewrite.contains('\n');
     let is_small_parent = parent_rewrite.len() <= context.config.tab_spaces();
 
@@ -297,7 +297,7 @@ pub fn rewrite_chain(expr: &ast::Expr, context: &RewriteContext, shape: Shape) -
             join_rewrites(&rewrites, &connector)
         )
     };
-    let result = format!("{}{}", result, repeat_try(suffix_try_num));
+    let result = format!("{}{}", result, "?".repeat(suffix_try_num));
     if context.config.indent_style() == IndentStyle::Visual {
         wrap_str(result, context.config.max_width(), shape)
     } else {
@@ -316,12 +316,6 @@ fn chain_only_try(exprs: &[ast::Expr]) -> bool {
     })
 }
 
-// Try to rewrite and replace the last non-try child. Return `true` if
-// replacing succeeds.
-fn repeat_try(try_count: usize) -> String {
-    iter::repeat("?").take(try_count).collect::<String>()
-}
-
 fn rewrite_try(
     expr: &ast::Expr,
     try_count: usize,
@@ -329,7 +323,7 @@ fn rewrite_try(
     shape: Shape,
 ) -> Option<String> {
     let sub_expr = expr.rewrite(context, shape.sub_width(try_count)?)?;
-    Some(format!("{}{}", sub_expr, repeat_try(try_count)))
+    Some(format!("{}{}", sub_expr, "?".repeat(try_count)))
 }
 
 fn join_rewrites(rewrites: &[String], connector: &str) -> String {
@@ -340,7 +334,7 @@ fn join_rewrites(rewrites: &[String], connector: &str) -> String {
         if rewrite != "?" {
             result.push_str(connector);
         }
-        result.push_str(&rewrite[..]);
+        result.push_str(&rewrite);
     }
 
     result
diff --git a/src/config/options.rs b/src/config/options.rs
index 31f7d106d1a3..eca206a75fe6 100644
--- a/src/config/options.rs
+++ b/src/config/options.rs
@@ -271,13 +271,7 @@ impl IgnoreList {
     }
 
     fn skip_file_inner(&self, file: &Path) -> bool {
-        for path in &self.0 {
-            if file.starts_with(path) {
-                return true;
-            }
-        }
-
-        false
+        self.0.iter().any(|path| file.starts_with(path))
     }
 
     pub fn skip_file(&self, file: &FileName) -> bool {
diff --git a/src/git-rustfmt/main.rs b/src/git-rustfmt/main.rs
index 41e4ee2931d4..3ff9455d5f79 100644
--- a/src/git-rustfmt/main.rs
+++ b/src/git-rustfmt/main.rs
@@ -32,16 +32,7 @@ fn prune_files(files: Vec<&str>) -> Vec<&str> {
 
     let mut pruned_prefixes = vec![];
     for p1 in prefixes {
-        let mut include = true;
-        if !p1.starts_with("src/bin/") {
-            for p2 in &pruned_prefixes {
-                if p1.starts_with(p2) {
-                    include = false;
-                    break;
-                }
-            }
-        }
-        if include {
+        if p1.starts_with("src/bin/") || pruned_prefixes.iter().all(|p2| !p1.starts_with(p2)) {
             pruned_prefixes.push(p1);
         }
     }
@@ -50,17 +41,10 @@ fn prune_files(files: Vec<&str>) -> Vec<&str> {
     files
         .into_iter()
         .filter(|f| {
-            let mut include = true;
             if f.ends_with("mod.rs") || f.ends_with("lib.rs") || f.starts_with("src/bin/") {
                 return true;
             }
-            for pp in &pruned_prefixes {
-                if f.starts_with(pp) {
-                    include = false;
-                    break;
-                }
-            }
-            include
+            pruned_prefixes.iter().all(|pp| !f.starts_with(pp))
         })
         .collect()
 }
diff --git a/src/items.rs b/src/items.rs
index 377d777c4099..621b2a2074db 100644
--- a/src/items.rs
+++ b/src/items.rs
@@ -204,7 +204,7 @@ impl<'a> FnSig<'a> {
         fn_kind: &'a visit::FnKind,
         generics: &'a ast::Generics,
         decl: &'a ast::FnDecl,
-        defualtness: ast::Defaultness,
+        defaultness: ast::Defaultness,
     ) -> FnSig<'a> {
         match *fn_kind {
             visit::FnKind::ItemFn(_, unsafety, constness, abi, visibility, _) => FnSig {
@@ -212,13 +212,13 @@ impl<'a> FnSig<'a> {
                 generics,
                 abi,
                 constness: constness.node,
-                defaultness: defualtness,
+                defaultness,
                 unsafety,
                 visibility: visibility.clone(),
             },
             visit::FnKind::Method(_, method_sig, vis, _) => {
                 let mut fn_sig = FnSig::from_method_sig(method_sig, generics);
-                fn_sig.defaultness = defualtness;
+                fn_sig.defaultness = defaultness;
                 if let Some(vis) = vis {
                     fn_sig.visibility = vis.clone();
                 }
@@ -1287,7 +1287,7 @@ fn format_tuple_struct(
         result.push(')');
     } else {
         let shape = Shape::indented(offset, context.config).sub_width(1)?;
-        let fields = &fields.iter().collect::<Vec<_>>()[..];
+        let fields = &fields.iter().collect::<Vec<_>>();
         result = overflow::rewrite_with_parens(
             context,
             &result,
@@ -2312,7 +2312,7 @@ fn rewrite_generics(
         return Some(ident.to_owned());
     }
 
-    let params = &generics.params.iter().map(|e| &*e).collect::<Vec<_>>()[..];
+    let params = &generics.params.iter().map(|e| &*e).collect::<Vec<_>>();
     overflow::rewrite_with_angle_brackets(context, ident, params, shape, span)
 }
 
diff --git a/src/lib.rs b/src/lib.rs
index 77589038c669..151b3acada27 100644
--- a/src/lib.rs
+++ b/src/lib.rs
@@ -34,7 +34,6 @@ extern crate unicode_segmentation;
 use std::collections::HashMap;
 use std::fmt;
 use std::io::{self, stdout, BufRead, Write};
-use std::iter::repeat;
 use std::panic::{catch_unwind, AssertUnwindSafe};
 use std::path::PathBuf;
 use std::rc::Rc;
@@ -200,7 +199,7 @@ impl FormatReport {
         for (file, errors) in &self.file_error_map {
             for error in errors {
                 let prefix_space_len = error.line.to_string().len();
-                let prefix_spaces: String = repeat(" ").take(1 + prefix_space_len).collect();
+                let prefix_spaces = " ".repeat(1 + prefix_space_len);
 
                 // First line: the overview of error
                 t.fg(term::color::RED)?;
@@ -259,8 +258,8 @@ impl FormatReport {
 }
 
 fn target_str(space_len: usize, target_len: usize) -> String {
-    let empty_line: String = repeat(" ").take(space_len).collect();
-    let overflowed: String = repeat("^").take(target_len).collect();
+    let empty_line = " ".repeat(space_len);
+    let overflowed = "^".repeat(target_len);
     empty_line + &overflowed
 }
 
@@ -270,7 +269,7 @@ impl fmt::Display for FormatReport {
         for (file, errors) in &self.file_error_map {
             for error in errors {
                 let prefix_space_len = error.line.to_string().len();
-                let prefix_spaces: String = repeat(" ").take(1 + prefix_space_len).collect();
+                let prefix_spaces = " ".repeat(1 + prefix_space_len);
 
                 let error_line_buffer = if error.line_buffer.is_empty() {
                     String::from(" ")
diff --git a/src/macros.rs b/src/macros.rs
index c5671911936c..aded2508aaa3 100644
--- a/src/macros.rs
+++ b/src/macros.rs
@@ -239,7 +239,7 @@ pub fn rewrite_macro_inner(
             overflow::rewrite_with_parens(
                 context,
                 &macro_name,
-                &arg_vec.iter().map(|e| &*e).collect::<Vec<_>>()[..],
+                &arg_vec.iter().map(|e| &*e).collect::<Vec<_>>(),
                 shape,
                 mac.span,
                 context.config.width_heuristics().fn_call_width,
@@ -301,7 +301,7 @@ pub fn rewrite_macro_inner(
                     };
                 }
                 // Convert `MacroArg` into `ast::Expr`, as `rewrite_array` only accepts the latter.
-                let arg_vec = &arg_vec.iter().map(|e| &*e).collect::<Vec<_>>()[..];
+                let arg_vec = &arg_vec.iter().map(|e| &*e).collect::<Vec<_>>();
                 let rewrite = rewrite_array(
                     macro_name,
                     arg_vec,
@@ -991,7 +991,7 @@ fn next_space(tok: &Token) -> SpaceState {
 /// when the macro is not an instance of try! (or parsing the inner expression
 /// failed).
 pub fn convert_try_mac(mac: &ast::Mac, context: &RewriteContext) -> Option<ast::Expr> {
-    if &format!("{}", mac.node.path)[..] == "try" {
+    if &format!("{}", mac.node.path) == "try" {
         let ts: TokenStream = mac.node.tts.clone().into();
         let mut parser = new_parser_from_tts(context.parse_session, ts.trees().collect());
 
diff --git a/src/missed_spans.rs b/src/missed_spans.rs
index 20cd5e6dca1d..b27ef9b87697 100644
--- a/src/missed_spans.rs
+++ b/src/missed_spans.rs
@@ -9,7 +9,6 @@
 // except according to those terms.
 
 use std::borrow::Cow;
-use std::iter::repeat;
 
 use syntax::codemap::{BytePos, FileName, Pos, Span};
 
@@ -128,7 +127,7 @@ impl<'a> FmtVisitor<'a> {
             }
         }
 
-        let blank_lines: String = repeat('\n').take(newline_count).collect();
+        let blank_lines = "\n".repeat(newline_count);
         self.push_str(&blank_lines);
     }
 
@@ -182,7 +181,7 @@ impl<'a> FmtVisitor<'a> {
         let mut status = SnippetStatus::new(char_pos.line);
 
         let snippet = &*match self.config.write_mode() {
-            WriteMode::Coverage => replace_chars(old_snippet),
+            WriteMode::Coverage => Cow::from(replace_chars(old_snippet)),
             _ => Cow::from(old_snippet),
         };
 
@@ -327,11 +326,9 @@ impl<'a> FmtVisitor<'a> {
     }
 }
 
-fn replace_chars(string: &str) -> Cow<str> {
-    Cow::from(
-        string
-            .chars()
-            .map(|ch| if ch.is_whitespace() { ch } else { 'X' })
-            .collect::<String>(),
-    )
+fn replace_chars(string: &str) -> String {
+    string
+        .chars()
+        .map(|ch| if ch.is_whitespace() { ch } else { 'X' })
+        .collect()
 }
diff --git a/src/patterns.rs b/src/patterns.rs
index 44e32462a8d4..bbfe55ec6e99 100644
--- a/src/patterns.rs
+++ b/src/patterns.rs
@@ -361,15 +361,12 @@ fn rewrite_tuple_pat(
     // add comma if `(x,)`
     let add_comma = path_str.is_none() && pat_vec.len() == 1 && dotdot_pos.is_none();
     let path_str = path_str.unwrap_or_default();
-    let mut pat_ref_vec = Vec::with_capacity(pat_vec.len());
-    for pat in pat_vec {
-        pat_ref_vec.push(pat);
-    }
+    let pat_ref_vec = pat_vec.iter().collect::<Vec<_>>();
 
     overflow::rewrite_with_parens(
         &context,
         &path_str,
-        &pat_ref_vec[..],
+        &pat_ref_vec,
         shape,
         span,
         context.config.max_width(),
@@ -408,7 +405,7 @@ fn count_wildcard_suffix_len(
     }) {
         suffix_len += 1;
 
-        if item.pre_comment.is_some() || item.post_comment.is_some() {
+        if item.has_comment() {
             break;
         }
     }
diff --git a/src/types.rs b/src/types.rs
index 676095ff4ce4..5be963481294 100644
--- a/src/types.rs
+++ b/src/types.rs
@@ -247,7 +247,7 @@ fn rewrite_segment(
                 let generics_str = overflow::rewrite_with_angle_brackets(
                     context,
                     "",
-                    &param_list.iter().map(|e| &*e).collect::<Vec<_>>()[..],
+                    &param_list.iter().map(|e| &*e).collect::<Vec<_>>(),
                     shape,
                     mk_sp(*span_lo, span_hi),
                 )?;
diff --git a/src/visitor.rs b/src/visitor.rs
index 22f892d4fb4a..d15d2ad7aefb 100644
--- a/src/visitor.rs
+++ b/src/visitor.rs
@@ -335,7 +335,7 @@ impl<'b, 'a: 'b> FmtVisitor<'a> {
                 let snippet = self.snippet(item.span);
                 let where_span_end = snippet
                     .find_uncommented("{")
-                    .map(|x| (BytePos(x as u32)) + source!(self, item.span).lo());
+                    .map(|x| BytePos(x as u32) + source!(self, item.span).lo());
                 let rw = format_impl(&self.get_context(), item, self.block_indent, where_span_end);
                 self.push_rewrite(item.span, rw);
             }