Avoid a hasOwnProperty bug in IE 10-11 where objects with a [[Prototype]] of null incorrectly report false for own index properties.

lodash.js

@@ -2322,7 +2322,13 @@
      * @returns {boolean} Returns `true` if `key` exists, else `false`.
      */
     function baseHas(object, key) {
-      return object != null && hasOwnProperty.call(object, key);
+      if (object == null) {
+        return false;
+      }
+      // Avoid a bug in IE 10-11 where objects with a [[Prototype]] of `null`
+      // incorrectly report `false` for own index properties.
+      return hasOwnProperty.call(object, key) ||
+        (typeof object == 'object' && key in object && getPrototypeOf(object) === null);
     }
 
     /**
@@ -3984,7 +3990,7 @@
       var index = objLength;
       while (index--) {
         var key = objProps[index];
-        if (!(isPartial ? key in other : hasOwnProperty.call(other, key)) ||
+        if (!(isPartial ? key in other : baseHas(other, key)) ||
             !(isUnordered || key == othProps[index])) {
           return false;
         }
@@ -9941,7 +9947,7 @@
           skipIndexes = !!length;
 
       for (var key in object) {
-        if (hasOwnProperty.call(object, key) &&
+        if (baseHas(object, key) &&
             !(skipIndexes && isIndex(key, length)) &&
             !(isProto && key == 'constructor')) {
           result.push(key);

test/test.js

@@ -6341,17 +6341,7 @@
       });
     });
 
-    QUnit.test('`_.' + methodName + '` should work with non-string `path` arguments', function(assert) {
+    QUnit.test('`_.' + methodName + '` should coerce `path` to a string', function(assert) {
-      assert.expect(2);
-
-      var array = [1, 2, 3];
-
-      _.each([1, [1]], function(path) {
-        assert.strictEqual(func(array, path), true);
-      });
-    });
-
-    QUnit.test('`_.' + methodName + '` should coerce key to a string', function(assert) {
       assert.expect(1);
 
       function fn() {}
@@ -6389,12 +6379,6 @@
       assert.strictEqual(func(Array(1), 0), true);
     });
 
-    QUnit.test('`_.' + methodName + '` should work with `arguments` objects', function(assert) {
-      assert.expect(1);
-
-      assert.strictEqual(func(args, 1), true);
-    });
-
     QUnit.test('`_.' + methodName + '` should check for a key over a path', function(assert) {
       assert.expect(2);
 
@@ -6444,6 +6428,35 @@
         assert.strictEqual(func(object, path), false);
       });
     });
+
+    QUnit.test('`_.' + methodName + '` should work with non-string `path` arguments', function(assert) {
+      assert.expect(2);
+
+      var array = [1, 2, 3];
+
+      _.each([1, [1]], function(path) {
+        assert.strictEqual(func(array, path), true);
+      });
+    });
+
+    QUnit.test('`_.' + methodName + '` should work with `arguments` objects', function(assert) {
+      assert.expect(1);
+
+      assert.strictEqual(func(args, 1), true);
+    });
+
+    QUnit.test('`_.' + methodName + '` should work for objects with a `[[Prototype]]` of `null`', function(assert) {
+      assert.expect(1);
+
+      if (create)  {
+        var object = create(null);
+        object[1] = 'a';
+        assert.strictEqual(func(object, 1), true);
+      }
+      else {
+        skipTest(assert);
+      }
+    });
   });
 
   /*--------------------------------------------------------------------------*/