diff --git a/.travis.yml b/.travis.yml
index 3d1c012ce..2cdfe0c4a 100644
--- a/.travis.yml
+++ b/.travis.yml
@@ -10,5 +10,9 @@ rust:
   - beta
   - nightly
 matrix:
+  include:
+    - rust: stable
+      env: DENYWARNINGS=1
   allow_failures:
+    - env: DENYWARNINGS=1
     - rust: nightly
diff --git a/_test/check-exercises.sh b/_test/check-exercises.sh
index d512652e0..c7d8831ca 100755
--- a/_test/check-exercises.sh
+++ b/_test/check-exercises.sh
@@ -1,9 +1,16 @@
 #!/bin/bash
 
-set -e
+# In DENYWARNINGS mode, do not set -e so that we run all tests.
+# This allows us to see all warnings.
+if [ -z "$DENYWARNINGS" ]; then
+    set -e
+fi
+
 tmp=${TMPDIR:-/tmp/}
 mkdir "${tmp}exercises"
 
+exitcode=0
+
 # An exercise worth testing is defined here as any top level directory with
 # a 'tests' directory
 for exercise in exercises/*/tests; do
@@ -19,6 +26,7 @@ for exercise in exercises/*/tests; do
     (
         cd $workdir
         [ -d src ] || mkdir src
+
         cp example.rs src/lib.rs
 
         # Forcibly strip all "ignore" statements from the testing files
@@ -26,15 +34,27 @@ for exercise in exercises/*/tests; do
             sed -i '/\[ignore\]/d' $test
         done
 
-        # Run the test and get the status
-        cargo test
+        if [ -n "$DENYWARNINGS" ]; then
+            sed -i -e '1i #![deny(warnings)]' src/lib.rs
+
+            # No-run mode so we see no test output.
+            # Quiet mode so we see no compile output
+            # (such as "Compiling"/"Downloading").
+            # Compiler errors will still be shown though.
+            # Both flags are necessary to keep things quiet.
+            cargo test --quiet --no-run
+        else
+            # Run the test and get the status
+            cargo test
+        fi
     )
 
     status=$?
 
     if [ $status -ne 0 ]
     then
-        echo "Failed";
-        return 1;
+        exitcode=1
     fi
 done
+
+exit $exitcode
diff --git a/exercises/tournament/example.rs b/exercises/tournament/example.rs
index 8d741007c..6359ce9c0 100644
--- a/exercises/tournament/example.rs
+++ b/exercises/tournament/example.rs
@@ -1,3 +1,5 @@
+use std::convert::AsRef;
+
 use std::cmp::Ordering::Equal;
 use std::collections::HashMap;
 use std::collections::hash_map::Entry;
diff --git a/exercises/word-count/example.rs b/exercises/word-count/example.rs
index 787c8fc3e..6d555841e 100644
--- a/exercises/word-count/example.rs
+++ b/exercises/word-count/example.rs
@@ -1,3 +1,5 @@
+use std::convert::AsRef;
+
 use std::collections::HashMap;
 use std::collections::hash_map::Entry;