diff --git a/src/compiletest/procsrv.rs b/src/compiletest/procsrv.rs
index 57f4171f7c2..4b0eea33d69 100644
--- a/src/compiletest/procsrv.rs
+++ b/src/compiletest/procsrv.rs
@@ -40,7 +40,7 @@ pub fn run(lib_path: &str,
     let mut cmd = Command::new(prog);
     cmd.args(args);
     add_target_env(&mut cmd, lib_path, aux_path);
-    for (key, val) in env.into_iter() {
+    for (key, val) in env {
         cmd.env(key, val);
     }
 
@@ -72,7 +72,7 @@ pub fn run_background(lib_path: &str,
     let mut cmd = Command::new(prog);
     cmd.args(args);
     add_target_env(&mut cmd, lib_path, aux_path);
-    for (key, val) in env.into_iter() {
+    for (key, val) in env {
         cmd.env(key, val);
     }
 
diff --git a/src/compiletest/runtest.rs b/src/compiletest/runtest.rs
index 2143cf22e05..3022973d9c1 100644
--- a/src/compiletest/runtest.rs
+++ b/src/compiletest/runtest.rs
@@ -1503,7 +1503,7 @@ fn _arm_exec_compiled_test(config: &Config,
 
     // run test via adb_run_wrapper
     runargs.push("shell".to_string());
-    for (key, val) in env.into_iter() {
+    for (key, val) in env {
         runargs.push(format!("{}={}", key, val));
     }
     runargs.push(format!("{}/adb_run_wrapper.sh", config.adb_test_dir));
diff --git a/src/libcollections/btree/map.rs b/src/libcollections/btree/map.rs
index bc657a19d78..23eab79e6a4 100644
--- a/src/libcollections/btree/map.rs
+++ b/src/libcollections/btree/map.rs
@@ -197,7 +197,7 @@ impl<K: Ord, V> BTreeMap<K, V> {
     pub fn clear(&mut self) {
         let b = self.b;
         // avoid recursive destructors by manually traversing the tree
-        for _ in mem::replace(self, BTreeMap::with_b(b)).into_iter() {};
+        for _ in mem::replace(self, BTreeMap::with_b(b)) {};
     }
 
     // Searching in a B-Tree is pretty straightforward.
diff --git a/src/libcollections/dlist.rs b/src/libcollections/dlist.rs
index e229cd8a961..c6c8a6e4a1e 100644
--- a/src/libcollections/dlist.rs
+++ b/src/libcollections/dlist.rs
@@ -1061,7 +1061,7 @@ mod tests {
         let mut sum = v;
         sum.push_all(u.as_slice());
         assert_eq!(sum.len(), m.len());
-        for elt in sum.into_iter() {
+        for elt in sum {
             assert_eq!(m.pop_front(), Some(elt))
         }
         assert_eq!(n.len(), 0);
diff --git a/src/libcollections/slice.rs b/src/libcollections/slice.rs
index 3830ab9ee7b..4b4ea3e4c3c 100644
--- a/src/libcollections/slice.rs
+++ b/src/libcollections/slice.rs
@@ -2699,7 +2699,7 @@ mod tests {
         }
         assert_eq!(cnt, 8);
 
-        for f in v.into_iter() {
+        for f in v {
             assert!(f == Foo);
             cnt += 1;
         }
diff --git a/src/libcollections/vec.rs b/src/libcollections/vec.rs
index acf4b480dfb..22b0e0f7cc9 100644
--- a/src/libcollections/vec.rs
+++ b/src/libcollections/vec.rs
@@ -2333,7 +2333,7 @@ mod tests {
     fn test_move_items() {
         let vec = vec![1, 2, 3];
         let mut vec2 : Vec<i32> = vec![];
-        for i in vec.into_iter() {
+        for i in vec {
             vec2.push(i);
         }
         assert!(vec2 == vec![1, 2, 3]);
@@ -2353,7 +2353,7 @@ mod tests {
     fn test_move_items_zero_sized() {
         let vec = vec![(), (), ()];
         let mut vec2 : Vec<()> = vec![];
-        for i in vec.into_iter() {
+        for i in vec {
             vec2.push(i);
         }
         assert!(vec2 == vec![(), (), ()]);
diff --git a/src/libcollections/vec_map.rs b/src/libcollections/vec_map.rs
index b07e172079e..e480d29541e 100644
--- a/src/libcollections/vec_map.rs
+++ b/src/libcollections/vec_map.rs
@@ -984,7 +984,7 @@ mod test_map {
         let mut m = VecMap::new();
         m.insert(1, box 2);
         let mut called = false;
-        for (k, v) in m.into_iter() {
+        for (k, v) in m {
             assert!(!called);
             called = true;
             assert_eq!(k, 1);
diff --git a/src/libcore/fmt/mod.rs b/src/libcore/fmt/mod.rs
index 20ef30b0a3e..ead49af18d0 100644
--- a/src/libcore/fmt/mod.rs
+++ b/src/libcore/fmt/mod.rs
@@ -482,7 +482,7 @@ impl<'a> Formatter<'a> {
 
         // Writes the sign if it exists, and then the prefix if it was requested
         let write_prefix = |&: f: &mut Formatter| {
-            for c in sign.into_iter() {
+            if let Some(c) = sign {
                 let mut b = [0; 4];
                 let n = c.encode_utf8(&mut b).unwrap_or(0);
                 let b = unsafe { str::from_utf8_unchecked(&b[..n]) };
diff --git a/src/librustc/lint/context.rs b/src/librustc/lint/context.rs
index 2bc29e61d0d..91dba90b0d2 100644
--- a/src/librustc/lint/context.rs
+++ b/src/librustc/lint/context.rs
@@ -417,11 +417,11 @@ pub fn raw_emit_lint(sess: &Session, lint: &'static Lint,
         _ => sess.bug("impossible level in raw_emit_lint"),
     }
 
-    for note in note.into_iter() {
+    if let Some(note) = note {
         sess.note(&note[]);
     }
 
-    for span in def.into_iter() {
+    if let Some(span) = def {
         sess.span_note(span, "lint level defined here");
     }
 }
@@ -492,7 +492,7 @@ impl<'a, 'tcx> Context<'a, 'tcx> {
         // specified closure
         let mut pushed = 0;
 
-        for result in gather_attrs(attrs).into_iter() {
+        for result in gather_attrs(attrs) {
             let v = match result {
                 Err(span) => {
                     self.tcx.sess.span_err(span, "malformed lint attribute");
@@ -519,7 +519,7 @@ impl<'a, 'tcx> Context<'a, 'tcx> {
                 }
             };
 
-            for (lint_id, level, span) in v.into_iter() {
+            for (lint_id, level, span) in v {
                 let now = self.lints.get_level_source(lint_id).0;
                 if now == Forbid && level != Forbid {
                     let lint_name = lint_id.as_str();
@@ -727,7 +727,7 @@ impl<'a, 'tcx> IdVisitingOperation for Context<'a, 'tcx> {
         match self.tcx.sess.lints.borrow_mut().remove(&id) {
             None => {}
             Some(lints) => {
-                for (lint_id, span, msg) in lints.into_iter() {
+                for (lint_id, span, msg) in lints {
                     self.span_lint(lint_id.lint, span, &msg[])
                 }
             }
diff --git a/src/librustc/metadata/encoder.rs b/src/librustc/metadata/encoder.rs
index 117ab4c8a5a..ccd524a2c03 100644
--- a/src/librustc/metadata/encoder.rs
+++ b/src/librustc/metadata/encoder.rs
@@ -1589,7 +1589,7 @@ fn encode_index<T, F>(rbml_w: &mut Encoder, index: Vec<entry<T>>, mut write_fn:
     T: Hash<SipHasher>,
 {
     let mut buckets: Vec<Vec<entry<T>>> = (0..256u16).map(|_| Vec::new()).collect();
-    for elt in index.into_iter() {
+    for elt in index {
         let mut s = SipHasher::new();
         elt.val.hash(&mut s);
         let h = s.finish() as uint;
diff --git a/src/librustc/metadata/loader.rs b/src/librustc/metadata/loader.rs
index f219bfffcb8..30b783cd509 100644
--- a/src/librustc/metadata/loader.rs
+++ b/src/librustc/metadata/loader.rs
@@ -425,7 +425,7 @@ impl<'a> Context<'a> {
         // libraries corresponds to the crate id and hash criteria that this
         // search is being performed for.
         let mut libraries = Vec::new();
-        for (_hash, (rlibs, dylibs)) in candidates.into_iter() {
+        for (_hash, (rlibs, dylibs)) in candidates {
             let mut metadata = None;
             let rlib = self.extract_one(rlibs, "rlib", &mut metadata);
             let dylib = self.extract_one(dylibs, "dylib", &mut metadata);
@@ -501,7 +501,7 @@ impl<'a> Context<'a> {
             }
         }
 
-        for (lib, kind) in m.into_iter() {
+        for (lib, kind) in m {
             info!("{} reading metadata from: {}", flavor, lib.display());
             let metadata = match get_metadata_section(self.target.options.is_like_osx,
                                                       &lib) {
diff --git a/src/librustc/middle/check_match.rs b/src/librustc/middle/check_match.rs
index 72551daa4e6..38084d1c2c0 100644
--- a/src/librustc/middle/check_match.rs
+++ b/src/librustc/middle/check_match.rs
@@ -77,7 +77,7 @@ impl<'a> fmt::Debug for Matrix<'a> {
         let total_width = column_widths.iter().map(|n| *n).sum() + column_count * 3 + 1;
         let br = repeat('+').take(total_width).collect::<String>();
         try!(write!(f, "{}\n", br));
-        for row in pretty_printed_matrix.into_iter() {
+        for row in pretty_printed_matrix {
             try!(write!(f, "+"));
             for (column, pat_str) in row.into_iter().enumerate() {
                 try!(write!(f, " "));
diff --git a/src/librustc/middle/dead.rs b/src/librustc/middle/dead.rs
index 6bad7f59441..4478e327087 100644
--- a/src/librustc/middle/dead.rs
+++ b/src/librustc/middle/dead.rs
@@ -318,7 +318,7 @@ fn has_allow_dead_code_or_lang_attr(attrs: &[ast::Attribute]) -> bool {
     }
 
     let dead_code = lint::builtin::DEAD_CODE.name_lower();
-    for attr in lint::gather_attrs(attrs).into_iter() {
+    for attr in lint::gather_attrs(attrs) {
         match attr {
             Ok((ref name, lint::Allow, _))
                 if name.get() == dead_code => return true,
diff --git a/src/librustc/middle/subst.rs b/src/librustc/middle/subst.rs
index 2cf8a83db9b..43319540c4e 100644
--- a/src/librustc/middle/subst.rs
+++ b/src/librustc/middle/subst.rs
@@ -352,7 +352,7 @@ impl<T> VecPerParamSpace<T> {
     pub fn replace(&mut self, space: ParamSpace, elems: Vec<T>) {
         // FIXME (#15435): slow; O(n^2); could enhance vec to make it O(n).
         self.truncate(space, 0);
-        for t in elems.into_iter() {
+        for t in elems {
             self.push(space, t);
         }
     }
diff --git a/src/librustc/middle/traits/fulfill.rs b/src/librustc/middle/traits/fulfill.rs
index ed058280483..8adcd256cce 100644
--- a/src/librustc/middle/traits/fulfill.rs
+++ b/src/librustc/middle/traits/fulfill.rs
@@ -125,7 +125,7 @@ impl<'tcx> FulfillmentContext<'tcx> {
         let mut selcx = SelectionContext::new(infcx, typer);
         let normalized = project::normalize_projection_type(&mut selcx, projection_ty, cause, 0);
 
-        for obligation in normalized.obligations.into_iter() {
+        for obligation in normalized.obligations {
             self.register_predicate_obligation(infcx, obligation);
         }
 
@@ -289,7 +289,7 @@ impl<'tcx> FulfillmentContext<'tcx> {
 
             // Now go through all the successful ones,
             // registering any nested obligations for the future.
-            for new_obligation in new_obligations.into_iter() {
+            for new_obligation in new_obligations {
                 self.register_predicate_obligation(selcx.infcx(), new_obligation);
             }
         }
diff --git a/src/librustc/middle/traits/mod.rs b/src/librustc/middle/traits/mod.rs
index 94da688181e..f69bf31626f 100644
--- a/src/librustc/middle/traits/mod.rs
+++ b/src/librustc/middle/traits/mod.rs
@@ -438,7 +438,7 @@ pub fn normalize_param_env<'a,'tcx>(param_env: &ty::ParameterEnvironment<'a,'tcx
         let mut fulfill_cx = FulfillmentContext::new();
         let Normalized { value: predicates, obligations } =
             project::normalize(selcx, cause, &param_env.caller_bounds);
-        for obligation in obligations.into_iter() {
+        for obligation in obligations {
             fulfill_cx.register_predicate_obligation(selcx.infcx(), obligation);
         }
         try!(fulfill_cx.select_all_or_error(selcx.infcx(), param_env));
diff --git a/src/librustc/plugin/load.rs b/src/librustc/plugin/load.rs
index 22edd7c691a..b9bf577b38e 100644
--- a/src/librustc/plugin/load.rs
+++ b/src/librustc/plugin/load.rs
@@ -204,7 +204,7 @@ impl<'a> PluginLoader<'a> {
             }
         }
 
-        for mut def in macros.into_iter() {
+        for mut def in macros {
             let name = token::get_ident(def.ident);
             def.use_locally = match macro_selection.as_ref() {
                 None => true,
diff --git a/src/librustc/session/config.rs b/src/librustc/session/config.rs
index afeb123b7a5..88f6dc673cf 100644
--- a/src/librustc/session/config.rs
+++ b/src/librustc/session/config.rs
@@ -300,7 +300,7 @@ macro_rules! options {
     pub fn $buildfn(matches: &getopts::Matches) -> $struct_name
     {
         let mut op = $defaultfn();
-        for option in matches.opt_strs($prefix).into_iter() {
+        for option in matches.opt_strs($prefix) {
             let mut iter = option.splitn(1, '=');
             let key = iter.next().unwrap();
             let value = iter.next();
@@ -831,7 +831,7 @@ pub fn build_session_options(matches: &getopts::Matches) -> Options {
     let mut describe_lints = false;
 
     for &level in &[lint::Allow, lint::Warn, lint::Deny, lint::Forbid] {
-        for lint_name in matches.opt_strs(level.as_str()).into_iter() {
+        for lint_name in matches.opt_strs(level.as_str()) {
             if lint_name == "help" {
                 describe_lints = true;
             } else {
diff --git a/src/librustc_driver/driver.rs b/src/librustc_driver/driver.rs
index e8ea349c3db..8d73532cf52 100644
--- a/src/librustc_driver/driver.rs
+++ b/src/librustc_driver/driver.rs
@@ -424,7 +424,7 @@ pub fn phase_2_configure_and_expand(sess: &Session,
                 diagnostics::plugin::expand_build_diagnostic_array);
         }
 
-        for registrar in registrars.into_iter() {
+        for registrar in registrars {
             registry.args_hidden = Some(registrar.args);
             (registrar.fun)(&mut registry);
         }
@@ -434,11 +434,11 @@ pub fn phase_2_configure_and_expand(sess: &Session,
 
     {
         let mut ls = sess.lint_store.borrow_mut();
-        for pass in lint_passes.into_iter() {
+        for pass in lint_passes {
             ls.register_pass(Some(sess), true, pass);
         }
 
-        for (name, to) in lint_groups.into_iter() {
+        for (name, to) in lint_groups {
             ls.register_group(Some(sess), true, name, to);
         }
     }
diff --git a/src/librustc_driver/lib.rs b/src/librustc_driver/lib.rs
index a8f5cfa6b3f..794d66e66ab 100644
--- a/src/librustc_driver/lib.rs
+++ b/src/librustc_driver/lib.rs
@@ -373,7 +373,7 @@ Available lint options:
     println!("    {}  {:7.7}  {}", padded("----"), "-------", "-------");
 
     let print_lints = |&: lints: Vec<&Lint>| {
-        for lint in lints.into_iter() {
+        for lint in lints {
             let name = lint.name_lower().replace("_", "-");
             println!("    {}  {:7.7}  {}",
                      padded(&name[]), lint.default_level.as_str(), lint.desc);
@@ -400,7 +400,7 @@ Available lint options:
     println!("    {}  {}", padded("----"), "---------");
 
     let print_lint_groups = |&: lints: Vec<(&'static str, Vec<lint::LintId>)>| {
-        for (name, to) in lints.into_iter() {
+        for (name, to) in lints {
             let name = name.chars().map(|x| x.to_lowercase())
                            .collect::<String>().replace("_", "-");
             let desc = to.into_iter().map(|x| x.as_str().replace("_", "-"))
diff --git a/src/librustc_resolve/lib.rs b/src/librustc_resolve/lib.rs
index c10b7124218..a5fb57eadc4 100644
--- a/src/librustc_resolve/lib.rs
+++ b/src/librustc_resolve/lib.rs
@@ -3607,10 +3607,10 @@ impl<'a, 'tcx> Resolver<'a, 'tcx> {
             TyQPath(ref qpath) => {
                 self.resolve_type(&*qpath.self_type);
                 self.resolve_trait_reference(ty.id, &*qpath.trait_ref, TraitQPath);
-                for ty in qpath.item_path.parameters.types().into_iter() {
+                for ty in qpath.item_path.parameters.types() {
                     self.resolve_type(&**ty);
                 }
-                for binding in qpath.item_path.parameters.bindings().into_iter() {
+                for binding in qpath.item_path.parameters.bindings() {
                     self.resolve_type(&*binding.ty);
                 }
             }
diff --git a/src/librustc_trans/back/link.rs b/src/librustc_trans/back/link.rs
index eeb6d9fab5e..145cf46ad9d 100644
--- a/src/librustc_trans/back/link.rs
+++ b/src/librustc_trans/back/link.rs
@@ -1275,7 +1275,7 @@ fn add_upstream_native_libraries(cmd: &mut Command, sess: &Session) {
     // we're just getting an ordering of crate numbers, we're not worried about
     // the paths.
     let crates = sess.cstore.get_used_crates(cstore::RequireStatic);
-    for (cnum, _) in crates.into_iter() {
+    for (cnum, _) in crates {
         let libs = csearch::get_native_libraries(&sess.cstore, cnum);
         for &(kind, ref lib) in &libs {
             match kind {
diff --git a/src/librustc_trans/back/lto.rs b/src/librustc_trans/back/lto.rs
index 1a5310bb0a8..38c68bc9fa4 100644
--- a/src/librustc_trans/back/lto.rs
+++ b/src/librustc_trans/back/lto.rs
@@ -48,7 +48,7 @@ pub fn run(sess: &session::Session, llmod: ModuleRef,
     // load the bitcode from the archive. Then merge it into the current LLVM
     // module that we've got.
     let crates = sess.cstore.get_used_crates(cstore::RequireStatic);
-    for (cnum, path) in crates.into_iter() {
+    for (cnum, path) in crates {
         let name = sess.cstore.get_crate_data(cnum).name.clone();
         let path = match path {
             Some(p) => p,
diff --git a/src/librustc_trans/back/write.rs b/src/librustc_trans/back/write.rs
index c54e3e02d3c..5312d2ca1dd 100644
--- a/src/librustc_trans/back/write.rs
+++ b/src/librustc_trans/back/write.rs
@@ -941,7 +941,7 @@ fn run_work_multithreaded(sess: &Session,
     }
 
     let mut panicked = false;
-    for rx in futures.into_iter() {
+    for rx in futures {
         match rx.recv() {
             Ok(()) => {},
             Err(_) => {
diff --git a/src/librustc_trans/trans/callee.rs b/src/librustc_trans/trans/callee.rs
index 5f3cb01d762..5f383d54a68 100644
--- a/src/librustc_trans/trans/callee.rs
+++ b/src/librustc_trans/trans/callee.rs
@@ -1045,7 +1045,7 @@ pub fn trans_args<'a, 'blk, 'tcx>(cx: Block<'blk, 'tcx>,
             }));
 
             assert_eq!(arg_tys.len(), 1 + rhs.len());
-            for (rhs, rhs_id) in rhs.into_iter() {
+            for (rhs, rhs_id) in rhs {
                 llargs.push(unpack_result!(bcx, {
                     trans_arg_datum(bcx, arg_tys[1], rhs,
                                     arg_cleanup_scope,
diff --git a/src/librustc_trans/trans/monomorphize.rs b/src/librustc_trans/trans/monomorphize.rs
index cc0d76efcf0..b3d388b0f02 100644
--- a/src/librustc_trans/trans/monomorphize.rs
+++ b/src/librustc_trans/trans/monomorphize.rs
@@ -333,7 +333,7 @@ pub fn normalize_associated_type<'tcx,T>(tcx: &ty::ctxt<'tcx>, value: &T) -> T
            obligations.repr(tcx));
 
     let mut fulfill_cx = traits::FulfillmentContext::new();
-    for obligation in obligations.into_iter() {
+    for obligation in obligations {
         fulfill_cx.register_predicate_obligation(&infcx, obligation);
     }
     let result = drain_fulfillment_cx(DUMMY_SP, &infcx, &mut fulfill_cx, &result);
diff --git a/src/librustc_typeck/astconv.rs b/src/librustc_typeck/astconv.rs
index 3bf34dfcd70..8809931cd80 100644
--- a/src/librustc_typeck/astconv.rs
+++ b/src/librustc_typeck/astconv.rs
@@ -537,7 +537,7 @@ pub fn instantiate_poly_trait_ref<'tcx>(
         instantiate_trait_ref(this, &shifted_rscope, &ast_trait_ref.trait_ref,
                               self_ty, Some(&mut projections));
 
-    for projection in projections.into_iter() {
+    for projection in projections {
         poly_projections.push(ty::Binder(projection));
     }
 
diff --git a/src/librustc_typeck/check/assoc.rs b/src/librustc_typeck/check/assoc.rs
index 0e0a9294640..377af080526 100644
--- a/src/librustc_typeck/check/assoc.rs
+++ b/src/librustc_typeck/check/assoc.rs
@@ -33,7 +33,7 @@ pub fn normalize_associated_types_in<'a,'tcx,T>(infcx: &InferCtxt<'a,'tcx>,
     debug!("normalize_associated_types_in: result={} predicates={}",
            result.repr(infcx.tcx),
            obligations.repr(infcx.tcx));
-    for obligation in obligations.into_iter() {
+    for obligation in obligations {
         fulfillment_cx.register_predicate_obligation(infcx, obligation);
     }
     result
diff --git a/src/librustc_typeck/check/compare_method.rs b/src/librustc_typeck/check/compare_method.rs
index 31b14ea3f3d..dc4d7d46647 100644
--- a/src/librustc_typeck/check/compare_method.rs
+++ b/src/librustc_typeck/check/compare_method.rs
@@ -248,7 +248,7 @@ pub fn compare_impl_method<'tcx>(tcx: &ty::ctxt<'tcx>,
 
     let mut selcx = traits::SelectionContext::new(&infcx, &trait_param_env);
 
-    for predicate in impl_pred.fns.into_iter() {
+    for predicate in impl_pred.fns {
         let traits::Normalized { value: predicate, .. } =
             traits::normalize(&mut selcx, normalize_cause.clone(), &predicate);
 
diff --git a/src/librustc_typeck/check/method/probe.rs b/src/librustc_typeck/check/method/probe.rs
index 8ad67b43178..a988fb4cc6e 100644
--- a/src/librustc_typeck/check/method/probe.rs
+++ b/src/librustc_typeck/check/method/probe.rs
@@ -448,7 +448,7 @@ impl<'a,'tcx> ProbeContext<'a,'tcx> {
     {
         let mut duplicates = HashSet::new();
         let opt_applicable_traits = self.fcx.ccx.trait_map.get(&expr_id);
-        for applicable_traits in opt_applicable_traits.into_iter() {
+        if let Some(applicable_traits) = opt_applicable_traits {
             for &trait_did in applicable_traits {
                 if duplicates.insert(trait_did) {
                     try!(self.assemble_extension_candidates_for_trait(trait_did));
diff --git a/src/librustc_typeck/check/vtable.rs b/src/librustc_typeck/check/vtable.rs
index 43910a937e8..6f66010925e 100644
--- a/src/librustc_typeck/check/vtable.rs
+++ b/src/librustc_typeck/check/vtable.rs
@@ -142,7 +142,7 @@ pub fn check_object_safety<'tcx>(tcx: &ty::ctxt<'tcx>,
               ty::item_path_str(tcx, object_trait_ref.def_id()));
 
     let violations = traits::object_safety_violations(tcx, object_trait_ref.clone());
-    for violation in violations.into_iter() {
+    for violation in violations {
         match violation {
             ObjectSafetyViolation::SizedSelf => {
                 tcx.sess.span_note(
@@ -269,7 +269,7 @@ fn check_object_type_binds_all_associated_types<'tcx>(tcx: &ty::ctxt<'tcx>,
         associated_types.remove(&pair);
     }
 
-    for (trait_def_id, name) in associated_types.into_iter() {
+    for (trait_def_id, name) in associated_types {
         span_err!(tcx.sess, span, E0191,
             "the value of the associated type `{}` (from the trait `{}`) must be specified",
                     name.user_string(tcx),
diff --git a/src/librustc_typeck/check/wf.rs b/src/librustc_typeck/check/wf.rs
index 24153fd94ea..71b495af444 100644
--- a/src/librustc_typeck/check/wf.rs
+++ b/src/librustc_typeck/check/wf.rs
@@ -268,10 +268,10 @@ impl<'ccx, 'tcx> CheckTypeWellFormedVisitor<'ccx, 'tcx> {
                 let selcx = &mut traits::SelectionContext::new(fcx.infcx(), fcx);
                 traits::normalize(selcx, cause.clone(), &predicates)
             };
-            for predicate in predicates.value.into_iter() {
+            for predicate in predicates.value {
                 fcx.register_predicate(traits::Obligation::new(cause.clone(), predicate));
             }
-            for obligation in predicates.obligations.into_iter() {
+            for obligation in predicates.obligations {
                 fcx.register_predicate(obligation);
             }
         });
diff --git a/src/librustc_typeck/collect.rs b/src/librustc_typeck/collect.rs
index 6d92343d332..4114e92a096 100644
--- a/src/librustc_typeck/collect.rs
+++ b/src/librustc_typeck/collect.rs
@@ -1109,7 +1109,7 @@ fn ty_generics_for_trait<'a, 'tcx>(ccx: &CollectCtxt<'a, 'tcx>,
 
     debug!("ty_generics_for_trait: assoc_predicates={}", assoc_predicates.repr(ccx.tcx));
 
-    for assoc_predicate in assoc_predicates.into_iter() {
+    for assoc_predicate in assoc_predicates {
         generics.predicates.push(subst::TypeSpace, assoc_predicate);
     }
 
@@ -1310,7 +1310,7 @@ fn ty_generics<'a,'tcx>(ccx: &CollectCtxt<'a,'tcx>,
     {
         for type_param_def in result.types.get_slice(space) {
             let param_ty = ty::mk_param_from_def(tcx, type_param_def);
-            for predicate in ty::predicates(tcx, param_ty, &type_param_def.bounds).into_iter() {
+            for predicate in ty::predicates(tcx, param_ty, &type_param_def.bounds) {
                 result.predicates.push(space, predicate);
             }
         }
diff --git a/src/librustdoc/html/render.rs b/src/librustdoc/html/render.rs
index 80e72777f93..6247c6dad14 100644
--- a/src/librustdoc/html/render.rs
+++ b/src/librustdoc/html/render.rs
@@ -1231,7 +1231,7 @@ impl Context {
                         _ => unreachable!()
                     };
                     this.sidebar = this.build_sidebar(&m);
-                    for item in m.items.into_iter() {
+                    for item in m.items {
                         f(this,item);
                     }
                     Ok(())
diff --git a/src/librustdoc/lib.rs b/src/librustdoc/lib.rs
index 9efd7cfb2e2..531e798a59f 100644
--- a/src/librustdoc/lib.rs
+++ b/src/librustdoc/lib.rs
@@ -431,7 +431,7 @@ fn rust_input(cratefile: &str, externs: core::Externs, matches: &getopts::Matche
         pm.add_plugin(plugin);
     }
     info!("loading plugins...");
-    for pname in plugins.into_iter() {
+    for pname in plugins {
         pm.load_plugin(pname);
     }
 
diff --git a/src/libserialize/json.rs b/src/libserialize/json.rs
index f43f22ec57c..3bc9e699035 100644
--- a/src/libserialize/json.rs
+++ b/src/libserialize/json.rs
@@ -2371,7 +2371,7 @@ impl ::Decoder for Decoder {
     {
         let obj = try!(expect!(self.pop(), Object));
         let len = obj.len();
-        for (key, value) in obj.into_iter() {
+        for (key, value) in obj {
             self.stack.push(value);
             self.stack.push(Json::String(key));
         }
diff --git a/src/libstd/old_io/fs.rs b/src/libstd/old_io/fs.rs
index 142f723ef71..e1006f23996 100644
--- a/src/libstd/old_io/fs.rs
+++ b/src/libstd/old_io/fs.rs
@@ -649,7 +649,7 @@ pub fn rmdir_recursive(path: &Path) -> IoResult<()> {
 
         // delete all regular files in the way and push subdirs
         // on the stack
-        for child in children.into_iter() {
+        for child in children {
             // FIXME(#12795) we should use lstat in all cases
             let child_type = match cfg!(windows) {
                 true => try!(update_err(stat(&child), path)),
diff --git a/src/libstd/old_io/net/mod.rs b/src/libstd/old_io/net/mod.rs
index d8394aa8b6a..bbe3a71dcc0 100644
--- a/src/libstd/old_io/net/mod.rs
+++ b/src/libstd/old_io/net/mod.rs
@@ -36,7 +36,7 @@ fn with_addresses<A, T, F>(addr: A, mut action: F) -> IoResult<T> where
 
     let addresses = try!(addr.to_socket_addr_all());
     let mut err = DEFAULT_ERROR;
-    for addr in addresses.into_iter() {
+    for addr in addresses {
         match action(addr) {
             Ok(r) => return Ok(r),
             Err(e) => err = e
diff --git a/src/libstd/rt/at_exit_imp.rs b/src/libstd/rt/at_exit_imp.rs
index 5823f8453d8..3f15cf71ec3 100644
--- a/src/libstd/rt/at_exit_imp.rs
+++ b/src/libstd/rt/at_exit_imp.rs
@@ -58,7 +58,7 @@ pub fn cleanup() {
         // If we never called init, not need to cleanup!
         if queue as uint != 0 {
             let queue: Box<Queue> = mem::transmute(queue);
-            for to_run in queue.into_iter() {
+            for to_run in *queue {
                 to_run.invoke(());
             }
         }
diff --git a/src/libstd/sync/rwlock.rs b/src/libstd/sync/rwlock.rs
index 95b570dd9c8..2dfc708e15b 100644
--- a/src/libstd/sync/rwlock.rs
+++ b/src/libstd/sync/rwlock.rs
@@ -508,7 +508,7 @@ mod tests {
         }
 
         // Wait for children to pass their asserts
-        for r in children.into_iter() {
+        for r in children {
             assert!(r.join().is_ok());
         }
 
diff --git a/src/libstd/sys/windows/process.rs b/src/libstd/sys/windows/process.rs
index a0a0c08ed09..58797111a20 100644
--- a/src/libstd/sys/windows/process.rs
+++ b/src/libstd/sys/windows/process.rs
@@ -147,7 +147,7 @@ impl Process {
 
                 // Split the value and test each path to see if the
                 // program exists.
-                for path in os::split_paths(v.container_as_bytes()).into_iter() {
+                for path in os::split_paths(v.container_as_bytes()) {
                     let path = path.join(cfg.program().as_bytes())
                                    .with_extension(os::consts::EXE_EXTENSION);
                     if path.exists() {
diff --git a/src/libsyntax/attr.rs b/src/libsyntax/attr.rs
index 61ddd240abc..e5cd6f63690 100644
--- a/src/libsyntax/attr.rs
+++ b/src/libsyntax/attr.rs
@@ -490,7 +490,7 @@ fn find_stability_generic<'a,
 pub fn find_stability(diagnostic: &SpanHandler, attrs: &[Attribute],
                       item_sp: Span) -> Option<Stability> {
     let (s, used) = find_stability_generic(diagnostic, attrs.iter(), item_sp);
-    for used in used.into_iter() { mark_used(used) }
+    for used in used { mark_used(used) }
     return s;
 }
 
diff --git a/src/libsyntax/ext/concat.rs b/src/libsyntax/ext/concat.rs
index 39895a3946a..4e10cc9aacc 100644
--- a/src/libsyntax/ext/concat.rs
+++ b/src/libsyntax/ext/concat.rs
@@ -25,7 +25,7 @@ pub fn expand_syntax_ext(cx: &mut base::ExtCtxt,
         None => return base::DummyResult::expr(sp)
     };
     let mut accumulator = String::new();
-    for e in es.into_iter() {
+    for e in es {
         match e.node {
             ast::ExprLit(ref lit) => {
                 match lit.node {
diff --git a/src/libsyntax/ext/expand.rs b/src/libsyntax/ext/expand.rs
index 8b4816f5d2b..2787339aac0 100644
--- a/src/libsyntax/ext/expand.rs
+++ b/src/libsyntax/ext/expand.rs
@@ -1420,11 +1420,11 @@ pub fn expand_crate(parse_sess: &parse::ParseSess,
     let mut cx = ExtCtxt::new(parse_sess, c.config.clone(), cfg);
     let mut expander = MacroExpander::new(&mut cx);
 
-    for def in imported_macros.into_iter() {
+    for def in imported_macros {
         expander.cx.insert_macro(def);
     }
 
-    for (name, extension) in user_exts.into_iter() {
+    for (name, extension) in user_exts {
         expander.cx.syntax_env.insert(name, extension);
     }
 
diff --git a/src/libsyntax/parse/parser.rs b/src/libsyntax/parse/parser.rs
index b7960d9e709..27fd803d3fe 100644
--- a/src/libsyntax/parse/parser.rs
+++ b/src/libsyntax/parse/parser.rs
@@ -5445,7 +5445,7 @@ 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,
diff --git a/src/libsyntax/print/pprust.rs b/src/libsyntax/print/pprust.rs
index 21cd02b3851..5c42485f239 100644
--- a/src/libsyntax/print/pprust.rs
+++ b/src/libsyntax/print/pprust.rs
@@ -966,7 +966,7 @@ impl<'a> State<'a> {
                 try!(self.print_generics(generics));
                 let bounds: Vec<_> = bounds.iter().map(|b| b.clone()).collect();
                 let mut real_bounds = Vec::with_capacity(bounds.len());
-                for b in bounds.into_iter() {
+                for b in bounds {
                     if let TraitTyParamBound(ref ptr, ast::TraitBoundModifier::Maybe) = b {
                         try!(space(&mut self.s));
                         try!(self.word_space("for ?"));
diff --git a/src/libtest/lib.rs b/src/libtest/lib.rs
index 63969e996d3..25377e3afa1 100644
--- a/src/libtest/lib.rs
+++ b/src/libtest/lib.rs
@@ -806,7 +806,7 @@ fn run_tests<F>(opts: &TestOpts,
 
     // All benchmarks run at the end, in serial.
     // (this includes metric fns)
-    for b in filtered_benchs_and_metrics.into_iter() {
+    for b in filtered_benchs_and_metrics {
         try!(callback(TeWait(b.desc.clone(), b.testfn.padding())));
         run_test(opts, !opts.run_benchmarks, b, tx.clone());
         let (test, result, stdout) = rx.recv().unwrap();
diff --git a/src/rustbook/build.rs b/src/rustbook/build.rs
index ccb572a113a..3c9c4bdedcc 100644
--- a/src/rustbook/build.rs
+++ b/src/rustbook/build.rs
@@ -177,7 +177,7 @@ impl Subcommand for Build {
             }
             Err(errors) => {
                 let n = errors.len();
-                for err in errors.into_iter() {
+                for err in errors {
                     term.err(&format!("error: {}", err)[]);
                 }
 
diff --git a/src/rustbook/test.rs b/src/rustbook/test.rs
index db02481cb02..d3cb8a7316e 100644
--- a/src/rustbook/test.rs
+++ b/src/rustbook/test.rs
@@ -64,7 +64,7 @@ impl Subcommand for Test {
                 }
             }
             Err(errors) => {
-                for err in errors.into_iter() {
+                for err in errors {
                     term.err(&err[]);
                 }
                 return Err(box "There was an error." as Box<Error>);
diff --git a/src/test/bench/msgsend-pipes-shared.rs b/src/test/bench/msgsend-pipes-shared.rs
index 6928397566d..259b4d9418d 100644
--- a/src/test/bench/msgsend-pipes-shared.rs
+++ b/src/test/bench/msgsend-pipes-shared.rs
@@ -75,7 +75,7 @@ fn run(args: &[String]) {
             server(&from_parent, &to_parent);
         });
 
-        for r in worker_results.into_iter() {
+        for r in worker_results {
             let _ = r.join();
         }
 
diff --git a/src/test/bench/msgsend-pipes.rs b/src/test/bench/msgsend-pipes.rs
index 9bf0ce1a590..1341c03e505 100644
--- a/src/test/bench/msgsend-pipes.rs
+++ b/src/test/bench/msgsend-pipes.rs
@@ -82,7 +82,7 @@ fn run(args: &[String]) {
             server(&from_parent, &to_parent);
         });
 
-        for r in worker_results.into_iter() {
+        for r in worker_results {
             let _ = r.join();
         }
 
diff --git a/src/test/bench/shootout-binarytrees.rs b/src/test/bench/shootout-binarytrees.rs
index 4182f8b651b..dc65a63c5cb 100644
--- a/src/test/bench/shootout-binarytrees.rs
+++ b/src/test/bench/shootout-binarytrees.rs
@@ -114,7 +114,7 @@ fn main() {
         Thread::scoped(move || inner(depth, iterations))
     }).collect::<Vec<_>>();
 
-    for message in messages.into_iter() {
+    for message in messages {
         println!("{}", message.join().ok().unwrap());
     }
 
diff --git a/src/test/bench/shootout-fannkuch-redux.rs b/src/test/bench/shootout-fannkuch-redux.rs
index 03666c84d57..47613e2d69c 100644
--- a/src/test/bench/shootout-fannkuch-redux.rs
+++ b/src/test/bench/shootout-fannkuch-redux.rs
@@ -171,7 +171,7 @@ fn fannkuch(n: i32) -> (i32, i32) {
 
     let mut checksum = 0;
     let mut maxflips = 0;
-    for fut in futures.into_iter() {
+    for fut in futures {
         let (cs, mf) = fut.join().ok().unwrap();
         checksum += cs;
         maxflips = cmp::max(maxflips, mf);
diff --git a/src/test/bench/shootout-k-nucleotide.rs b/src/test/bench/shootout-k-nucleotide.rs
index a7a47ff07ce..e3f8e60df93 100644
--- a/src/test/bench/shootout-k-nucleotide.rs
+++ b/src/test/bench/shootout-k-nucleotide.rs
@@ -308,7 +308,7 @@ fn main() {
         Thread::scoped(move|| generate_frequencies(input.as_slice(), occ.len()))
     }).collect();
 
-    for (i, freq) in nb_freqs.into_iter() {
+    for (i, freq) in nb_freqs {
         print_frequencies(&freq.join().ok().unwrap(), i);
     }
     for (&occ, freq) in OCCURRENCES.iter().zip(occ_freqs.into_iter()) {
diff --git a/src/test/bench/shootout-mandelbrot.rs b/src/test/bench/shootout-mandelbrot.rs
index 754b891eb63..3bd786a3be0 100644
--- a/src/test/bench/shootout-mandelbrot.rs
+++ b/src/test/bench/shootout-mandelbrot.rs
@@ -106,7 +106,7 @@ fn mandelbrot<W: old_io::Writer>(w: uint, mut out: W) -> old_io::IoResult<()> {
         })
     }).collect::<Vec<_>>();
 
-    for res in precalc_futures.into_iter() {
+    for res in precalc_futures {
         let (rs, is) = res.join().ok().unwrap();
         precalc_r.extend(rs.into_iter());
         precalc_i.extend(is.into_iter());
@@ -142,7 +142,7 @@ fn mandelbrot<W: old_io::Writer>(w: uint, mut out: W) -> old_io::IoResult<()> {
     }).collect::<Vec<_>>();
 
     try!(writeln!(&mut out as &mut Writer, "P4\n{} {}", w, h));
-    for res in data.into_iter() {
+    for res in data {
         try!(out.write(res.join().ok().unwrap().as_slice()));
     }
     out.flush()
diff --git a/src/test/bench/shootout-pfib.rs b/src/test/bench/shootout-pfib.rs
index dd3ae1699a9..ea1d913b3e2 100644
--- a/src/test/bench/shootout-pfib.rs
+++ b/src/test/bench/shootout-pfib.rs
@@ -82,7 +82,7 @@ fn stress(num_tasks: int) {
             stress_task(i);
         }));
     }
-    for r in results.into_iter() {
+    for r in results {
         let _ = r.join();
     }
 }
diff --git a/src/test/debuginfo/destructured-for-loop-variable.rs b/src/test/debuginfo/destructured-for-loop-variable.rs
index 163771a2362..0d526d60190 100644
--- a/src/test/debuginfo/destructured-for-loop-variable.rs
+++ b/src/test/debuginfo/destructured-for-loop-variable.rs
@@ -215,7 +215,7 @@ fn main() {
       zzz(); // #break
     }
 
-    for simple_tuple_ident in vec![(34903493u32, 232323i64)].into_iter() {
+    for simple_tuple_ident in vec![(34903493u32, 232323i64)] {
       zzz(); // #break
     }
 }
diff --git a/src/test/run-pass/task-comm-3.rs b/src/test/run-pass/task-comm-3.rs
index 4aec3d608ac..90282946838 100644
--- a/src/test/run-pass/task-comm-3.rs
+++ b/src/test/run-pass/task-comm-3.rs
@@ -61,7 +61,7 @@ fn test00() {
     }
 
     // Join spawned tasks...
-    for r in results.into_iter() { r.join(); }
+    for r in results { r.join(); }
 
     println!("Completed: Final number is: ");
     println!("{}", sum);
diff --git a/src/test/run-pass/unboxed-closures-counter-not-moved.rs b/src/test/run-pass/unboxed-closures-counter-not-moved.rs
index e921f0c723e..0b85916d224 100644
--- a/src/test/run-pass/unboxed-closures-counter-not-moved.rs
+++ b/src/test/run-pass/unboxed-closures-counter-not-moved.rs
@@ -21,7 +21,7 @@ fn main() {
     call(|| {
         // Move `y`, but do not move `counter`, even though it is read
         // by value (note that it is also mutated).
-        for item in y.into_iter() {
+        for item in y {
             let v = counter;
             counter += v;
         }
diff --git a/src/test/run-pass/unboxed-closures-move-some-upvars-in-by-ref-closure.rs b/src/test/run-pass/unboxed-closures-move-some-upvars-in-by-ref-closure.rs
index 9534ee6fa12..99663646254 100644
--- a/src/test/run-pass/unboxed-closures-move-some-upvars-in-by-ref-closure.rs
+++ b/src/test/run-pass/unboxed-closures-move-some-upvars-in-by-ref-closure.rs
@@ -22,7 +22,7 @@ fn main() {
         // Here: `x` must be captured with a mutable reference in
         // order for us to append on it, and `y` must be captured by
         // value.
-        for item in y.into_iter() {
+        for item in y {
             x.push(item);
         }
     });