diff --git a/src/cargo/cargo.rs b/src/cargo/cargo.rs
index fd39797b29f..87e8be75787 100644
--- a/src/cargo/cargo.rs
+++ b/src/cargo/cargo.rs
@@ -573,7 +573,7 @@ fn install_named_specific(c: cargo, wd: str, src: str, name: str) {
     error("Can't find package " + src + "/" + name);
 }
 
-fn cmd_install(c: cargo, argv: [str]) {
+fn cmd_install(c: cargo, argv: [str]) unsafe {
     // cargo install <pkg>
     if vec::len(argv) < 3u {
         cmd_usage();
@@ -596,8 +596,9 @@ fn cmd_install(c: cargo, argv: [str]) {
         let uuid = rest(target, 5u);
         let idx = str::index(uuid, '/' as u8);
         if idx != -1 {
-            let source = str::slice(uuid, 0u, idx as uint);
-            uuid = str::slice(uuid, idx as uint + 1u, str::byte_len(uuid));
+            let source = str::unsafe::slice(uuid, 0u, idx as uint);
+            uuid = str::unsafe::slice(uuid, idx as uint + 1u,
+                                      str::byte_len(uuid));
             install_uuid_specific(c, wd, source, uuid);
         } else {
             install_uuid(c, wd, uuid);
@@ -606,8 +607,9 @@ fn cmd_install(c: cargo, argv: [str]) {
         let name = target;
         let idx = str::index(name, '/' as u8);
         if idx != -1 {
-            let source = str::slice(name, 0u, idx as uint);
-            name = str::slice(name, idx as uint + 1u, str::byte_len(name));
+            let source = str::unsafe::slice(name, 0u, idx as uint);
+            name = str::unsafe::slice(name, idx as uint + 1u,
+                                      str::byte_len(name));
             install_named_specific(c, wd, source, name);
         } else {
             install_named(c, wd, name);
diff --git a/src/fuzzer/fuzzer.rs b/src/fuzzer/fuzzer.rs
index 7d5156a95a0..a6b1c13943a 100644
--- a/src/fuzzer/fuzzer.rs
+++ b/src/fuzzer/fuzzer.rs
@@ -283,10 +283,10 @@ fn check_variants_T<T: copy>(
     }
 }
 
-fn last_part(filename: str) -> str {
+fn last_part(filename: str) -> str unsafe {
   let ix = str::rindex(filename, 47u8 /* '/' */);
   assert ix >= 0;
-  str::slice(filename, ix as uint + 1u, str::byte_len(filename) - 3u)
+  str::unsafe::slice(filename, ix as uint + 1u, str::byte_len(filename) - 3u)
 }
 
 enum happiness { passed, cleanly_rejected(str), known_bug(str), failed(str), }
diff --git a/src/libstd/json.rs b/src/libstd/json.rs
index 306bcf6e16a..cf0c236afeb 100644
--- a/src/libstd/json.rs
+++ b/src/libstd/json.rs
@@ -228,9 +228,9 @@ fn from_str_float(s: str) -> (option<json>, str) {
 
 fn from_str_bool(s: str) -> (option<json>, str) {
     if (str::starts_with(s, "true")) {
-        (some(boolean(true)), str::slice(s, 4u, str::byte_len(s)))
+        (some(boolean(true)), str::char_slice(s, 4u, str::char_len(s)))
     } else if (str::starts_with(s, "false")) {
-        (some(boolean(false)), str::slice(s, 5u, str::byte_len(s)))
+        (some(boolean(false)), str::char_slice(s, 5u, str::char_len(s)))
     } else {
         (none, s)
     }
@@ -238,7 +238,7 @@ fn from_str_bool(s: str) -> (option<json>, str) {
 
 fn from_str_null(s: str) -> (option<json>, str) {
     if (str::starts_with(s, "null")) {
-        (some(null), str::slice(s, 4u, str::byte_len(s)))
+        (some(null), str::char_slice(s, 4u, str::char_len(s)))
     } else {
         (none, s)
     }