diff --git a/src/librustc/middle/borrowck/loan.rs b/src/librustc/middle/borrowck/loan.rs
index c4b36085ec8..0b06fbd2a3a 100644
--- a/src/librustc/middle/borrowck/loan.rs
+++ b/src/librustc/middle/borrowck/loan.rs
@@ -33,7 +33,7 @@ mutability M_L, and a lifetime L_L where:
   - immutable/mutable: the data cannot be moved or mutated
 - The lifetime L_L indicates the *scope* of the loan.
 
-XXX --- much more needed, don't have time to write this all up now
+FIXME #4730 --- much more needed, don't have time to write this all up now
 
 */
 
diff --git a/src/librustc/middle/check_match.rs b/src/librustc/middle/check_match.rs
index 406fdbaeac7..5ec5a2c7c88 100644
--- a/src/librustc/middle/check_match.rs
+++ b/src/librustc/middle/check_match.rs
@@ -516,7 +516,7 @@ pub fn specialize(cx: @MatchCheckCtxt,
                     }
                     def_variant(_, _) => None,
                     def_struct(*) => {
-                        // XXX: Is this right? --pcw
+                        // FIXME #4731: Is this right? --pcw
                         let new_args;
                         match args {
                             Some(args) => new_args = args,
@@ -545,7 +545,7 @@ pub fn specialize(cx: @MatchCheckCtxt,
                 match cx.tcx.def_map.get(pat_id) {
                     def_variant(_, variant_id) => {
                         if variant(variant_id) == ctor_id {
-                            // XXX: Is this right? --pcw
+                            // FIXME #4731: Is this right? --pcw
                             let args = flds.map(|ty_field| {
                                 match flds.find(|f|
                                                 f.ident == ty_field.ident) {
diff --git a/src/librustc/middle/liveness.rs b/src/librustc/middle/liveness.rs
index 0cafe528d04..5d57f680200 100644
--- a/src/librustc/middle/liveness.rs
+++ b/src/librustc/middle/liveness.rs
@@ -1754,7 +1754,8 @@ impl @Liveness {
         // used by ExitNode would be arguments or fields in a ctor.
         // we give a slightly different error message in those cases.
         if lnk == ExitNode {
-            // XXX this seems like it should be reported in the borrow checker
+            // FIXME #4715: this seems like it should be reported in the
+            // borrow checker
             let vk = self.ir.var_kinds[*var];
             match vk {
               Arg(_, name, _) => {
diff --git a/src/librustc/middle/privacy.rs b/src/librustc/middle/privacy.rs
index eb90acb2d36..482f01f7201 100644
--- a/src/librustc/middle/privacy.rs
+++ b/src/librustc/middle/privacy.rs
@@ -131,7 +131,7 @@ pub fn check_crate(tcx: ty::ctxt,
                         }
                     }
                 } else {
-                    // XXX: External crates.
+                    // FIXME #4732: External crates.
                 }
             }
             method_param(method_param {
@@ -195,7 +195,7 @@ pub fn check_crate(tcx: ty::ctxt,
                         }
                     }
                 } else {
-                    // XXX: External crates.
+                    // FIXME #4732: External crates.
                 }
             }
         }