diff --git a/.eslintrc b/.eslintrc
index 7c161435..4a8fb4a0 100644
--- a/.eslintrc
+++ b/.eslintrc
@@ -25,6 +25,11 @@
             "named": "never",
         }],
         "no-extra-semi": "error",
+        "no-shadow": ["error", {
+            "builtinGlobals": false,
+            "hoist": "functions",
+            "allow": []
+        }],
         "no-undef": "error",
         "no-useless-escape": "error",
         "object-curly-newline": ["error", {
diff --git a/bin/tape b/bin/tape
index a912c087..027fbb1b 100755
--- a/bin/tape
+++ b/bin/tape
@@ -47,13 +47,13 @@ if (typeof opts.ignore === 'string') {
 var files = opts._.reduce(function (result, arg) {
     // If glob does not match, `files` will be an empty array.
     // Note: `glob.sync` may throw an error and crash the node process.
-    var files = glob.sync(arg);
+    var globFiles = glob.sync(arg);
 
-    if (!Array.isArray(files)) {
+    if (!Array.isArray(globFiles)) {
         throw new TypeError('unknown error: glob.sync("' + arg + '") did not return an array or throw. Please report this.');
     }
 
-    return result.concat(files);
+    return result.concat(globFiles);
 }, []).filter(function (file) {
     return !matcher || !matcher.shouldIgnore(file);
 }).map(function (file) {
@@ -75,13 +75,13 @@ function importFiles(hasSupport) {
 
     tape.wait();
 
-    var promise = files.reduce(function (promise, file) {
+    var filesPromise = files.reduce(function (promise, file) {
         return promise ? promise.then(function () {
             return importOrRequire(file);
         }) : importOrRequire(file);
     }, null);
 
-    return promise ? promise.then(function () { tape.run(); }) : tape.run();
+    return filesPromise ? filesPromise.then(function () { tape.run(); }) : tape.run();
 }
 
 // vim: ft=javascript
diff --git a/lib/test.js b/lib/test.js
index 37a85348..71325f52 100644
--- a/lib/test.js
+++ b/lib/test.js
@@ -423,7 +423,7 @@ Test.prototype.skip = function skip(msg, extra) {
     });
 };
 
-function assert(value, msg, extra) {
+var testAssert = function assert(value, msg, extra) {
     this._assert(value, {
         message: defined(msg, 'should be truthy'),
         operator: 'ok',
@@ -431,11 +431,11 @@ function assert(value, msg, extra) {
         actual: value,
         extra: extra
     });
-}
+};
 Test.prototype.ok
 = Test.prototype['true']
 = Test.prototype.assert
-= assert;
+= testAssert;
 
 function notOK(value, msg, extra) {
     this._assert(!value, {
diff --git a/test/async-await/async5.js b/test/async-await/async5.js
index a58930ec..eca3bc4a 100644
--- a/test/async-await/async5.js
+++ b/test/async-await/async5.js
@@ -33,8 +33,8 @@ test('async5', async function myTest(t) {
                 port: server.address().port,
                 path: '/',
                 method: 'GET'
-            }, function (res) {
-                cb(null, res);
+            }, function (resp) {
+                cb(null, resp);
             });
             req.end();
         })();
diff --git a/test/child_ordering.js b/test/child_ordering.js
index c2cb2c29..6c75f587 100644
--- a/test/child_ordering.js
+++ b/test/child_ordering.js
@@ -5,10 +5,10 @@ var test = require('../');
 var childRan = false;
 
 test('parent', function (t) {
-    t.test('child', function (t) {
+    t.test('child', function (st) {
         childRan = true;
-        t.pass('child ran');
-        t.end();
+        st.pass('child ran');
+        st.end();
     });
     t.end();
 });
@@ -24,22 +24,22 @@ var grandChildRan = false;
 test('grandparent', function (t) {
     t.ok(!grandParentRan, 'grand parent ran twice');
     grandParentRan = true;
-    t.test('parent', function (t) {
-        t.ok(!parentRan, 'parent ran twice');
+    t.test('parent', function (st) {
+        st.ok(!parentRan, 'parent ran twice');
         parentRan = true;
-        t.test('grandchild', function (t) {
-            t.ok(!grandChildRan, 'grand child ran twice');
+        st.test('grandchild', function (s2t) {
+            s2t.ok(!grandChildRan, 'grand child ran twice');
             grandChildRan = true;
-            t.pass('grand child ran');
-            t.end();
+            s2t.pass('grand child ran');
+            s2t.end();
         });
-        t.pass('parent ran');
-        t.end();
+        st.pass('parent ran');
+        st.end();
     });
-    t.test('other parent', function (t) {
-        t.ok(parentRan, 'first parent runs before second parent');
-        t.ok(grandChildRan, 'grandchild runs before second parent');
-        t.end();
+    t.test('other parent', function (st) {
+        st.ok(parentRan, 'first parent runs before second parent');
+        st.ok(grandChildRan, 'grandchild runs before second parent');
+        st.end();
     });
     t.pass('grandparent ran');
     t.end();
diff --git a/test/nested2.js b/test/nested2.js
index 130b9583..685fd15a 100644
--- a/test/nested2.js
+++ b/test/nested2.js
@@ -4,17 +4,17 @@ var test = require('../');
 
 test(function (t) {
     var i = 0;
-    t.test('setup', function (t) {
+    t.test('setup', function (st) {
         process.nextTick(function () {
-            t.equal(i, 0, 'called once');
+            st.equal(i, 0, 'called once');
             i++;
-            t.end();
+            st.end();
         });
     });
 
 
-    t.test('teardown', function (t) {
-        t.end();
+    t.test('teardown', function (st) {
+        st.end();
     });
 
     t.end();
diff --git a/test/objectMode.js b/test/objectMode.js
index 0145a691..fd71d8cc 100644
--- a/test/objectMode.js
+++ b/test/objectMode.js
@@ -24,21 +24,21 @@ tap.test('object results', function (assert) {
 
         assert.equal(objects.length, 13);
 
-        forEach(objects, function (obj) {
-            if (obj.type === 'assert') {
+        forEach(objects, function (object) {
+            if (object.type === 'assert') {
                 asserts++;
-            } else if (obj.type === 'test') {
-                testIds.push(obj.id);
+            } else if (object.type === 'test') {
+                testIds.push(object.id);
 
-                if (obj.skip) {
+                if (object.skip) {
                     skips++;
-                } else if (obj.todo) {
+                } else if (object.todo) {
                     todos++;
                 }
-            } else if (obj.type === 'end') {
-                endIds.push(obj.text);
+            } else if (object.type === 'end') {
+                endIds.push(object.text);
                 // test object should exist
-                assert.notEqual(testIds.indexOf(obj.test), -1);
+                assert.notEqual(testIds.indexOf(object.test), -1);
             }
         });
 
diff --git a/test/promises/subTests.js b/test/promises/subTests.js
index a4a6b129..bb8d0d9b 100644
--- a/test/promises/subTests.js
+++ b/test/promises/subTests.js
@@ -4,14 +4,14 @@ var test = require('../../');
 
 if (typeof Promise === 'function' && typeof Promise.resolve === 'function') {
     test('promise', function (t) {
-        t.test('sub test that should fail', function (t) {
+        t.test('sub test that should fail', function () {
             return new Promise(function (resolve, reject) {
                 reject(new Error('rejection message'));
             });
         });
-        t.test('sub test that should pass', function (t) {
-            t.plan(1);
-            t.ok(true);
+        t.test('sub test that should pass', function (st) {
+            st.plan(1);
+            st.ok(true);
         });
     });
 } else {
diff --git a/test/skip.js b/test/skip.js
index 6682f048..7a1523de 100644
--- a/test/skip.js
+++ b/test/skip.js
@@ -44,9 +44,9 @@ test.skip('skip this too', function (t) {
 
 test('skip subtest', function (t) {
     ran++;
-    t.test('skip this', { skip: true }, function (t) {
-        t.fail('this should not even run');
-        t.end();
+    t.test('skip this', { skip: true }, function (st) {
+        st.fail('this should not even run');
+        st.end();
     });
     t.end();
 });
diff --git a/test/subcount.js b/test/subcount.js
index 09cb1358..62b94746 100644
--- a/test/subcount.js
+++ b/test/subcount.js
@@ -4,13 +4,13 @@ var test = require('../');
 
 test('parent test', function (t) {
     t.plan(2);
-    t.test('first child', function (t) {
-        t.plan(1);
-        t.pass('pass first child');
+    t.test('first child', function (st) {
+        st.plan(1);
+        st.pass('pass first child');
     });
 
-    t.test(function (t) {
-        t.plan(1);
-        t.pass('pass second child');
+    t.test(function (st) {
+        st.plan(1);
+        st.pass('pass second child');
     });
 });
diff --git a/test/subtest_plan.js b/test/subtest_plan.js
index 9bab4730..b3063b96 100644
--- a/test/subtest_plan.js
+++ b/test/subtest_plan.js
@@ -9,15 +9,15 @@ test('parent', function (t) {
 
     t.pass('assertion in parent');
 
-    t.test('first child', function (t) {
-        t.plan(1);
-        t.pass('pass first child');
+    t.test('first child', function (st) {
+        st.plan(1);
+        st.pass('pass first child');
         firstChildRan = true;
     });
 
-    t.test('second child', function (t) {
-        t.plan(2);
-        t.ok(firstChildRan, 'first child ran first');
-        t.pass('pass second child');
+    t.test('second child', function (st) {
+        st.plan(2);
+        st.ok(firstChildRan, 'first child ran first');
+        st.pass('pass second child');
     });
 });
diff --git a/test/throws.js b/test/throws.js
index c0cb895d..e2a6d609 100644
--- a/test/throws.js
+++ b/test/throws.js
@@ -8,18 +8,6 @@ var assign = require('object.assign');
 
 var stripFullStack = require('./common').stripFullStack;
 
-function fn() {
-    throw new TypeError('RegExp');
-}
-
-function getNonFunctionMessage(fn) {
-    try {
-        fn();
-    } catch (e) {
-        return e.message;
-    }
-}
-
 var getter = function () { return 'message'; };
 var messageGetterError = Object.defineProperty(
     { custom: 'error' },