diff --git a/src/libextra/timer.rs b/src/libextra/timer.rs
index f251336666309..7a4ad34b50892 100644
--- a/src/libextra/timer.rs
+++ b/src/libextra/timer.rs
@@ -131,7 +131,6 @@ pub fn recv_timeout<T:Copy + Owned>(iotask: &IoTask,
     unsafe {
         let wait_po = cast::transmute_mut(wait_po);
 
-        // FIXME: This could be written clearer (#2618)
         either::either(
             |_| {
                 None
diff --git a/src/libstd/pipes.rs b/src/libstd/pipes.rs
index 1137540ae7061..012ad0ed80d26 100644
--- a/src/libstd/pipes.rs
+++ b/src/libstd/pipes.rs
@@ -315,6 +315,7 @@ struct BufferResource<T> {
 impl<T> Drop for BufferResource<T> {
     fn finalize(&self) {
         unsafe {
+            // FIXME(#4330) Need self by value to get mutability.
             let this: &mut BufferResource<T> = transmute(self);
 
             let mut b = move_it!(this.buffer);
diff --git a/src/libstd/rt/rc.rs b/src/libstd/rt/rc.rs
index 1c0c8c14fdfa6..2977d08150812 100644
--- a/src/libstd/rt/rc.rs
+++ b/src/libstd/rt/rc.rs
@@ -78,7 +78,7 @@ impl<T> Drop for RC<T> {
         assert!(self.refcount() > 0);
 
         unsafe {
-            // XXX: Mutable finalizer
+            // FIXME(#4330) Need self by value to get mutability.
             let this: &mut RC<T> = cast::transmute_mut(self);
 
             match *this.get_mut_state() {
diff --git a/src/libstd/rt/uv/mod.rs b/src/libstd/rt/uv/mod.rs
index 10c8b84bc512a..dd66a76eead91 100644
--- a/src/libstd/rt/uv/mod.rs
+++ b/src/libstd/rt/uv/mod.rs
@@ -238,20 +238,6 @@ pub fn last_uv_error<H, W: Watcher + NativeHandle<*H>>(watcher: &W) -> UvError {
 }
 
 pub fn uv_error_to_io_error(uverr: UvError) -> IoError {
-
-    // XXX: Could go in str::raw
-    unsafe fn c_str_to_static_slice(s: *libc::c_char) -> &'static str {
-        let s = s as *u8;
-        let mut (curr, len) = (s, 0u);
-        while *curr != 0u8 {
-            len += 1u;
-            curr = ptr::offset(s, len);
-        }
-
-        str::raw::buf_as_slice(s, len, |d| cast::transmute(d))
-    }
-
-
     unsafe {
         // Importing error constants
         use rt::uv::uvll::*;
@@ -259,7 +245,7 @@ pub fn uv_error_to_io_error(uverr: UvError) -> IoError {
 
         // uv error descriptions are static
         let c_desc = uvll::strerror(&*uverr);
-        let desc = c_str_to_static_slice(c_desc);
+        let desc = str::raw::c_str_to_static_slice(c_desc);
 
         let kind = match uverr.code {
             UNKNOWN => OtherIoError,
diff --git a/src/libstd/run.rs b/src/libstd/run.rs
index 41bc573f10d3f..85015c9bc5e41 100644
--- a/src/libstd/run.rs
+++ b/src/libstd/run.rs
@@ -429,7 +429,7 @@ impl Process {
 
 impl Drop for Process {
     fn finalize(&self) {
-        // FIXME #4943: transmute is bad.
+        // FIXME(#4330) Need self by value to get mutability.
         let mut_self: &mut Process = unsafe { cast::transmute(self) };
 
         mut_self.finish();
diff --git a/src/libstd/str.rs b/src/libstd/str.rs
index 8cd69f32e4969..f270964c3b569 100644
--- a/src/libstd/str.rs
+++ b/src/libstd/str.rs
@@ -1396,12 +1396,19 @@ pub mod raw {
     /// Converts a byte to a string.
     pub unsafe fn from_byte(u: u8) -> ~str { raw::from_bytes([u]) }
 
-    /// Form a slice from a *u8 buffer of the given length without copying.
-    pub unsafe fn buf_as_slice<T>(buf: *u8, len: uint,
-                              f: &fn(v: &str) -> T) -> T {
-        let v = (buf, len + 1);
+    /// Form a slice from a C string. Unsafe because the caller must ensure the
+    /// C string has the static lifetime, or else the return value may be
+    /// invalidated later.
+    pub unsafe fn c_str_to_static_slice(s: *libc::c_char) -> &'static str {
+        let s = s as *u8;
+        let mut (curr, len) = (s, 0u);
+        while *curr != 0u8 {
+            len += 1u;
+            curr = ptr::offset(s, len);
+        }
+        let v = (s, len + 1);
         assert!(is_utf8(::cast::transmute(v)));
-        f(::cast::transmute(v))
+        ::cast::transmute(v)
     }
 
     /**
diff --git a/src/libstd/task/spawn.rs b/src/libstd/task/spawn.rs
index 87e9296657f48..bc409e066330b 100644
--- a/src/libstd/task/spawn.rs
+++ b/src/libstd/task/spawn.rs
@@ -323,6 +323,7 @@ impl Drop for TCB {
     // Runs on task exit.
     fn finalize(&self) {
         unsafe {
+            // FIXME(#4330) Need self by value to get mutability.
             let this: &mut TCB = transmute(self);
 
             // If we are failing, the whole taskgroup needs to die.
diff --git a/src/libstd/unstable/atomics.rs b/src/libstd/unstable/atomics.rs
index 58d0c01f990d0..856f4e6e3c196 100644
--- a/src/libstd/unstable/atomics.rs
+++ b/src/libstd/unstable/atomics.rs
@@ -275,6 +275,7 @@ impl<T> Drop for AtomicOption<T> {
         // This will ensure that the contained data is
         // destroyed, unless it's null.
         unsafe {
+            // FIXME(#4330) Need self by value to get mutability.
             let this : &mut AtomicOption<T> = cast::transmute(self);
             let _ = this.take(SeqCst);
         }