diff --git a/src/libextra/crypto/md5.rs b/src/libextra/crypto/md5.rs
index 8e8b752da80..8e07c7ee1c7 100644
--- a/src/libextra/crypto/md5.rs
+++ b/src/libextra/crypto/md5.rs
@@ -8,7 +8,7 @@
 // option. This file may not be copied, modified, or distributed
 // except according to those terms.
 
-use std::uint;
+use std::iter::range_step;
 
 use cryptoutil::{write_u32_le, read_u32v_le, FixedBuffer, FixedBuffer64, StandardPadding};
 use digest::Digest;
@@ -86,46 +86,42 @@ impl Md5State {
         read_u32v_le(data, input);
 
         // round 1
-        do uint::range_step(0, 16, 4) |i| {
+        for i in range_step(0u, 16, 4) {
             a = op_f(a, b, c, d, data[i] + C1[i], 7);
             d = op_f(d, a, b, c, data[i + 1] + C1[i + 1], 12);
             c = op_f(c, d, a, b, data[i + 2] + C1[i + 2], 17);
             b = op_f(b, c, d, a, data[i + 3] + C1[i + 3], 22);
-            true
-        };
+        }
 
         // round 2
         let mut t = 1;
-        do uint::range_step(0, 16, 4) |i| {
+        for i in range_step(0u, 16, 4) {
             a = op_g(a, b, c, d, data[t & 0x0f] + C2[i], 5);
             d = op_g(d, a, b, c, data[(t + 5) & 0x0f] + C2[i + 1], 9);
             c = op_g(c, d, a, b, data[(t + 10) & 0x0f] + C2[i + 2], 14);
             b = op_g(b, c, d, a, data[(t + 15) & 0x0f] + C2[i + 3], 20);
             t += 20;
-            true
-        };
+        }
 
         // round 3
         t = 5;
-        do uint::range_step(0, 16, 4) |i| {
+        for i in range_step(0u, 16, 4) {
             a = op_h(a, b, c, d, data[t & 0x0f] + C3[i], 4);
             d = op_h(d, a, b, c, data[(t + 3) & 0x0f] + C3[i + 1], 11);
             c = op_h(c, d, a, b, data[(t + 6) & 0x0f] + C3[i + 2], 16);
             b = op_h(b, c, d, a, data[(t + 9) & 0x0f] + C3[i + 3], 23);
             t += 12;
-            true
-        };
+        }
 
         // round 4
         t = 0;
-        do uint::range_step(0, 16, 4) |i| {
+        for i in range_step(0u, 16, 4) {
             a = op_i(a, b, c, d, data[t & 0x0f] + C4[i], 6);
             d = op_i(d, a, b, c, data[(t + 7) & 0x0f] + C4[i + 1], 10);
             c = op_i(c, d, a, b, data[(t + 14) & 0x0f] + C4[i + 2], 15);
             b = op_i(b, c, d, a, data[(t + 21) & 0x0f] + C4[i + 3], 21);
             t += 28;
-            true
-        };
+        }
 
         self.s0 += a;
         self.s1 += b;
diff --git a/src/libextra/crypto/sha2.rs b/src/libextra/crypto/sha2.rs
index 49bbddca1db..10289fb8b97 100644
--- a/src/libextra/crypto/sha2.rs
+++ b/src/libextra/crypto/sha2.rs
@@ -8,7 +8,7 @@
 // option. This file may not be copied, modified, or distributed
 // except according to those terms.
 
-use std::uint;
+use std::iter::range_step;
 
 use cryptoutil::{write_u64_be, write_u32_be, read_u64v_be, read_u32v_be, add_bytes_to_bits,
     add_bytes_to_bits_tuple, FixedBuffer, FixedBuffer128, FixedBuffer64, StandardPadding};
@@ -111,7 +111,7 @@ impl Engine512State {
 
         // Putting the message schedule inside the same loop as the round calculations allows for
         // the compiler to generate better code.
-        do uint::range_step(0, 64, 8) |t| {
+        for t in range_step(0u, 64, 8) {
             schedule_round!(t + 16);
             schedule_round!(t + 17);
             schedule_round!(t + 18);
@@ -129,10 +129,9 @@ impl Engine512State {
             sha2_round!(d, e, f, g, h, a, b, c, K64, t + 5);
             sha2_round!(c, d, e, f, g, h, a, b, K64, t + 6);
             sha2_round!(b, c, d, e, f, g, h, a, K64, t + 7);
-            true
-        };
+        }
 
-        do uint::range_step(64, 80, 8) |t| {
+        for t in range_step(64u, 80, 8) {
             sha2_round!(a, b, c, d, e, f, g, h, K64, t);
             sha2_round!(h, a, b, c, d, e, f, g, K64, t + 1);
             sha2_round!(g, h, a, b, c, d, e, f, K64, t + 2);
@@ -141,8 +140,7 @@ impl Engine512State {
             sha2_round!(d, e, f, g, h, a, b, c, K64, t + 5);
             sha2_round!(c, d, e, f, g, h, a, b, K64, t + 6);
             sha2_round!(b, c, d, e, f, g, h, a, K64, t + 7);
-            true
-        };
+        }
 
         self.H0 += a;
         self.H1 += b;
@@ -527,7 +525,7 @@ impl Engine256State {
 
         // Putting the message schedule inside the same loop as the round calculations allows for
         // the compiler to generate better code.
-        do uint::range_step(0, 48, 8) |t| {
+        for t in range_step(0u, 48, 8) {
             schedule_round!(t + 16);
             schedule_round!(t + 17);
             schedule_round!(t + 18);
@@ -545,10 +543,9 @@ impl Engine256State {
             sha2_round!(d, e, f, g, h, a, b, c, K32, t + 5);
             sha2_round!(c, d, e, f, g, h, a, b, K32, t + 6);
             sha2_round!(b, c, d, e, f, g, h, a, K32, t + 7);
-            true
-        };
+        }
 
-        do uint::range_step(48, 64, 8) |t| {
+        for t in range_step(48u, 64, 8) {
             sha2_round!(a, b, c, d, e, f, g, h, K32, t);
             sha2_round!(h, a, b, c, d, e, f, g, K32, t + 1);
             sha2_round!(g, h, a, b, c, d, e, f, K32, t + 2);
@@ -557,8 +554,7 @@ impl Engine256State {
             sha2_round!(d, e, f, g, h, a, b, c, K32, t + 5);
             sha2_round!(c, d, e, f, g, h, a, b, K32, t + 6);
             sha2_round!(b, c, d, e, f, g, h, a, K32, t + 7);
-            true
-        };
+        }
 
         self.H0 += a;
         self.H1 += b;
diff --git a/src/libstd/char.rs b/src/libstd/char.rs
index 3a01e5908d9..911d883f88a 100644
--- a/src/libstd/char.rs
+++ b/src/libstd/char.rs
@@ -12,7 +12,7 @@
 
 use cast::transmute;
 use option::{None, Option, Some};
-use i32;
+use iter::{Iterator, range_step};
 use str::StrSlice;
 use unicode::{derived_property, general_category, decompose};
 use to_str::ToStr;
@@ -286,15 +286,14 @@ pub fn escape_unicode(c: char, f: &fn(char)) {
         (c <= '\uffff') { f('u'); 4 }
         _               { f('U'); 8 }
     );
-    do i32::range_step(4 * (pad - 1), -1, -4) |offset| {
+    for offset in range_step::<i32>(4 * (pad - 1), -1, -4) {
         unsafe {
             match ((c as i32) >> offset) & 0xf {
                 i @ 0 .. 9 => { f(transmute('0' as i32 + i)); }
                 i => { f(transmute('a' as i32 + (i - 10))); }
             }
         }
-        true
-    };
+    }
 }
 
 ///
diff --git a/src/libstd/rand.rs b/src/libstd/rand.rs
index 813901207bb..1330096ee36 100644
--- a/src/libstd/rand.rs
+++ b/src/libstd/rand.rs
@@ -48,7 +48,7 @@ use clone::Clone;
 use cmp;
 use container::Container;
 use int;
-use iter::{Iterator, range};
+use iter::{Iterator, range, range_step};
 use local_data;
 use num;
 use prelude::*;
@@ -748,7 +748,7 @@ impl IsaacRng {
         if use_rsl {
             macro_rules! memloop (
                 ($arr:expr) => {{
-                    do u32::range_step(0, RAND_SIZE, 8) |i| {
+                    for i in range_step(0u32, RAND_SIZE, 8) {
                         a+=$arr[i  ]; b+=$arr[i+1];
                         c+=$arr[i+2]; d+=$arr[i+3];
                         e+=$arr[i+4]; f+=$arr[i+5];
@@ -758,22 +758,20 @@ impl IsaacRng {
                         self.mem[i+2]=c; self.mem[i+3]=d;
                         self.mem[i+4]=e; self.mem[i+5]=f;
                         self.mem[i+6]=g; self.mem[i+7]=h;
-                        true
-                    };
+                    }
                 }}
             );
 
             memloop!(self.rsl);
             memloop!(self.mem);
         } else {
-            do u32::range_step(0, RAND_SIZE, 8) |i| {
+            for i in range_step(0u32, RAND_SIZE, 8) {
                 mix!();
                 self.mem[i  ]=a; self.mem[i+1]=b;
                 self.mem[i+2]=c; self.mem[i+3]=d;
                 self.mem[i+4]=e; self.mem[i+5]=f;
                 self.mem[i+6]=g; self.mem[i+7]=h;
-                true
-            };
+            }
         }
 
         self.isaac();
@@ -794,7 +792,7 @@ impl IsaacRng {
         });
         macro_rules! rngstep(
             ($j:expr, $shift:expr) => {{
-                let base = base + $j;
+                let base = $j;
                 let mix = if $shift < 0 {
                     a >> -$shift as uint
                 } else {
@@ -813,13 +811,12 @@ impl IsaacRng {
 
         let r = [(0, MIDPOINT), (MIDPOINT, 0)];
         for &(mr_offset, m2_offset) in r.iter() {
-            do uint::range_step(0, MIDPOINT, 4) |base| {
-                rngstep!(0, 13);
-                rngstep!(1, -6);
-                rngstep!(2, 2);
-                rngstep!(3, -16);
-                true
-            };
+            for i in range_step(0u, MIDPOINT, 4) {
+                rngstep!(i + 0, 13);
+                rngstep!(i + 1, -6);
+                rngstep!(i + 2, 2);
+                rngstep!(i + 3, -16);
+            }
         }
 
         self.a = a;
diff --git a/src/libstd/trie.rs b/src/libstd/trie.rs
index 32797216376..88a953a1601 100644
--- a/src/libstd/trie.rs
+++ b/src/libstd/trie.rs
@@ -520,6 +520,7 @@ pub fn check_integrity<T>(trie: &TrieNode<T>) {
 mod test_map {
     use super::*;
     use prelude::*;
+    use iter::range_step;
     use uint;
 
     #[test]
@@ -538,21 +539,19 @@ mod test_map {
     #[test]
     fn test_step() {
         let mut trie = TrieMap::new();
-        let n = 300;
+        let n = 300u;
 
-        do uint::range_step(1, n, 2) |x| {
+        for x in range_step(1u, n, 2) {
             assert!(trie.insert(x, x + 1));
             assert!(trie.contains_key(&x));
             check_integrity(&trie.root);
-            true
-        };
+        }
 
-        do uint::range_step(0, n, 2) |x| {
+        for x in range_step(0u, n, 2) {
             assert!(!trie.contains_key(&x));
             assert!(trie.insert(x, x + 1));
             check_integrity(&trie.root);
-            true
-        };
+        }
 
         for x in range(0u, n) {
             assert!(trie.contains_key(&x));
@@ -560,19 +559,17 @@ mod test_map {
             check_integrity(&trie.root);
         }
 
-        do uint::range_step(1, n, 2) |x| {
+        for x in range_step(1u, n, 2) {
             assert!(trie.remove(&x));
             assert!(!trie.contains_key(&x));
             check_integrity(&trie.root);
-            true
-        };
+        }
 
-        do uint::range_step(0, n, 2) |x| {
+        for x in range_step(0u, n, 2) {
             assert!(trie.contains_key(&x));
             assert!(!trie.insert(x, x + 1));
             check_integrity(&trie.root);
-            true
-        };
+        }
     }
 
     #[test]
@@ -715,11 +712,10 @@ mod test_map {
         let value = 42u;
 
         let mut map : TrieMap<uint> = TrieMap::new();
-        do uint::range_step(0u, last, step as int) |x| {
+        for x in range_step(0u, last, step) {
             assert!(x % step == 0);
             map.insert(x, value);
-            true
-        };
+        }
 
         for i in range(0u, last - step) {
             let mut lb = map.lower_bound_iter(i);
diff --git a/src/test/run-pass/num-range-rev.rs b/src/test/run-pass/num-range-rev.rs
index ea7d4a651f7..05b84c059c4 100644
--- a/src/test/run-pass/num-range-rev.rs
+++ b/src/test/run-pass/num-range-rev.rs
@@ -28,11 +28,11 @@ fn int_range_rev(hi: int,  lo: int, it: &fn(int) -> bool) -> bool {
 }
 
 fn int_range_step(a: int, b: int, step: int, it: &fn(int) -> bool) -> bool {
-    int::range_step(a, b, step, it)
+    std::iter::range_step(a, b, step).advance(it)
 }
 
 fn uint_range_step(a: uint, b: uint, step: int, it: &fn(uint) -> bool) -> bool {
-    uint::range_step(a, b, step, it)
+    std::iter::range_step(a, b, step).advance(it)
 }
 
 
diff --git a/src/test/run-pass/num-range.rs b/src/test/run-pass/num-range.rs
index 7376edef8a8..5f87d01719e 100644
--- a/src/test/run-pass/num-range.rs
+++ b/src/test/run-pass/num-range.rs
@@ -20,11 +20,11 @@ fn int_range(lo: int, hi: int, it: &fn(int) -> bool) -> bool {
 }
 
 fn int_range_step(a: int, b: int, step: int, it: &fn(int) -> bool) -> bool {
-    int::range_step(a, b, step, it)
+    std::iter::range_step(a, b, step).advance(it)
 }
 
 fn uint_range_step(a: uint, b: uint, s: int, it: &fn(uint) -> bool) -> bool {
-    uint::range_step(a, b, s, it)
+    std::iter::range_step(a, b, s).advance(it)
 }
 
 pub fn main() {
@@ -98,35 +98,31 @@ pub fn main() {
 
     // range_step_inclusive will never pass stop element, and may skip it.
     let mut saw21 = false;
-    do uint::range_step_inclusive(0, 21, 4) |x| {
+    for x in std::iter::range_step_inclusive(0, 21, 4) {
         assert!(x <= 21);
         if x == 21 { saw21 = true; }
-        true
-    };
+    }
     assert!(!saw21);
     let mut saw21 = false;
-    do int::range_step_inclusive(0, 21, 4) |x| {
+    for x in std::iter::range_step_inclusive(0, 21, 4) {
         assert!(x <= 21);
         if x == 21 { saw21 = true; }
-        true
-    };
+    }
     assert!(!saw21);
 
     // range_step_inclusive will never pass stop element, but may visit it.
     let mut saw21 = false;
-    do uint::range_step_inclusive(0, 21, 3) |x| {
+    for x in std::iter::range_step_inclusive(0, 21, 3) {
         assert!(x <= 21);
         printfln!("saw: %u", x);
         if x == 21 { saw21 = true; }
-        true
-    };
+    }
     assert!(saw21);
     let mut saw21 = false;
-    do int::range_step_inclusive(0, 21, 3) |x| {
+    for x in std::iter::range_step_inclusive(0, 21, 3) {
         assert!(x <= 21);
         if x == 21 { saw21 = true; }
-        true
-    };
+    }
     assert!(saw21);
 
 }