diff --git a/src/librustc/middle/graph.rs b/src/librustc/middle/graph.rs
index 804dc88746c..e37df6eda2d 100644
--- a/src/librustc/middle/graph.rs
+++ b/src/librustc/middle/graph.rs
@@ -34,7 +34,6 @@ be indexed by the direction (see the type `Direction`).
 
 */
 
-use std::prelude::*;
 use std::uint;
 use std::vec;
 
diff --git a/src/librustc/middle/trans/meth.rs b/src/librustc/middle/trans/meth.rs
index fed8c5e800e..4c401af8e8e 100644
--- a/src/librustc/middle/trans/meth.rs
+++ b/src/librustc/middle/trans/meth.rs
@@ -548,7 +548,6 @@ pub fn trans_trait_callee_from_llval(bcx: block,
 
     let _icx = push_ctxt("impl::trans_trait_callee");
     let ccx = bcx.ccx();
-    let bcx = bcx;
 
     // Load the vtable from the @Trait pair
     debug!("(translating trait callee) loading vtable from pair %s",
diff --git a/src/librustc/middle/typeck/infer/error_reporting.rs b/src/librustc/middle/typeck/infer/error_reporting.rs
index ae8cab4c4db..21f3fdf7b2c 100644
--- a/src/librustc/middle/typeck/infer/error_reporting.rs
+++ b/src/librustc/middle/typeck/infer/error_reporting.rs
@@ -372,9 +372,9 @@ impl ErrorReporting for InferCtxt {
                     sup,
                     "");
             }
-            infer::ReferenceOutlivesReferent(ty, _) => {
+            infer::ReferenceOutlivesReferent(ty, span) => {
                 self.tcx.sess.span_err(
-                    origin.span(),
+                    span,
                     fmt!("in type `%s`, pointer has a longer lifetime than \
                           the data it references",
                          ty.user_string(self.tcx)));
diff --git a/src/librustc/util/ppaux.rs b/src/librustc/util/ppaux.rs
index ae91713be04..07dd19a3fed 100644
--- a/src/librustc/util/ppaux.rs
+++ b/src/librustc/util/ppaux.rs
@@ -752,7 +752,7 @@ impl Repr for typeck::method_param {
 }
 
 impl Repr for ty::RegionVid {
-    fn repr(&self, tcx: ctxt) -> ~str {
+    fn repr(&self, _tcx: ctxt) -> ~str {
         fmt!("%?", *self)
     }
 }