rollup merge of #21830: japaric/for-cleanup

Conflicts:
	src/librustc/metadata/filesearch.rs
	src/librustc_back/target/mod.rs
	src/libstd/os.rs
	src/libstd/sys/windows/os.rs
	src/libsyntax/ext/tt/macro_parser.rs
	src/libsyntax/print/pprust.rs
	src/test/compile-fail/issue-2149.rs

src/libsyntax/parse/lexer/comments.rs

@@ -90,7 +90,7 @@ pub fn strip_doc_comment_decoration(comment: &str) -> String {
         let mut i = usize::MAX;
         let mut can_trim = true;
         let mut first = true;
-        for line in lines.iter() {
+        for line in &lines {
             for (j, c) in line.chars().enumerate() {
                 if j > i || !"* \t".contains_char(c) {
                     can_trim = false;
@@ -125,7 +125,7 @@ pub fn strip_doc_comment_decoration(comment: &str) -> String {
 
     // one-line comments lose their prefix
     static ONLINERS: &'static [&'static str] = &["///!", "///", "//!", "//"];
-    for prefix in ONLINERS.iter() {
+    for prefix in ONLINERS {
         if comment.starts_with(*prefix) {
             return (&comment[prefix.len()..]).to_string();
         }

src/libsyntax/parse/lexer/mod.rs

@@ -1526,7 +1526,7 @@ mod test {
     // check that the given reader produces the desired stream
     // of tokens (stop checking after exhausting the expected vec)
     fn check_tokenization (mut string_reader: StringReader, expected: Vec<token::Token> ) {
-        for expected_tok in expected.iter() {
+        for expected_tok in &expected {
             assert_eq!(&string_reader.next_token().tok, expected_tok);
         }
     }

src/libsyntax/parse/mod.rs

@@ -1164,7 +1164,7 @@ mod test {
                     "impl z { fn a (self: Foo, &myarg: i32) {} }",
                     ];
 
-        for &src in srcs.iter() {
+        for &src in &srcs {
             let spans = get_spans_of_pat_idents(src);
             let Span{ lo, hi, .. } = spans[0];
             assert!("self" == &src[lo.to_usize()..hi.to_usize()],

src/libsyntax/parse/parser.rs

@@ -2713,7 +2713,7 @@ impl<'a> Parser<'a> {
         match self.token {
             token::Eof => {
                 let open_braces = self.open_braces.clone();
-                for sp in open_braces.iter() {
+                for sp in &open_braces {
                     self.span_help(*sp, "did you mean to close this delimiter?");
                 }
                 // There shouldn't really be a span, but it's easier for the test runner
@@ -5207,7 +5207,7 @@ impl<'a> Parser<'a> {
             Some(i) => {
                 let mut err = String::from_str("circular modules: ");
                 let len = included_mod_stack.len();
-                for p in included_mod_stack[i.. len].iter() {
+                for p in &included_mod_stack[i.. len] {
                     err.push_str(&p.display().as_cow()[]);
                     err.push_str(" -> ");
                 }
@@ -5452,7 +5452,7 @@ impl<'a> Parser<'a> {
                     seq_sep_trailing_allowed(token::Comma),
                     |p| p.parse_ty_sum()
                 );
-                for ty in arg_tys.into_iter() {
+                for ty in arg_tys {
                     args.push(ast::VariantArg {
                         ty: ty,
                         id: ast::DUMMY_NODE_ID,