diff --git a/.travis.yml b/.travis.yml
index 21f3d35..c7129ca 100644
--- a/.travis.yml
+++ b/.travis.yml
@@ -2,7 +2,6 @@ sudo: required
 language: generic
 services: docker
 env:
-- HHVM_VERSION=latest
 - HHVM_VERSION=nightly
 install:
 - docker pull hhvm/hhvm:$HHVM_VERSION
diff --git a/composer.json b/composer.json
index 69d5332..a6ce45c 100644
--- a/composer.json
+++ b/composer.json
@@ -10,6 +10,6 @@
   },
   "require-dev": {
     "hhvm/hhvm-autoload": "^2.0",
-    "hhvm/hhast": "^4.0"
+    "hhvm/hhast": "^4.1"
   }
 }
diff --git a/composer.lock b/composer.lock
index be995ba..9f20a99 100644
--- a/composer.lock
+++ b/composer.lock
@@ -4,7 +4,7 @@
         "Read more about it at https://getcomposer.org/doc/01-basic-usage.md#installing-dependencies",
         "This file is @generated automatically"
     ],
-    "content-hash": "a643b2edb9bf4064ff9576471565d917",
+    "content-hash": "930a83f29f9b0fb8b77ef5ca13c0409f",
     "packages": [
         {
             "name": "facebook/difflib",
@@ -282,22 +282,22 @@
     "packages-dev": [
         {
             "name": "hhvm/hhast",
-            "version": "v4.0.5",
+            "version": "v4.1.0",
             "source": {
                 "type": "git",
                 "url": "https://github.com/hhvm/hhast.git",
-                "reference": "a5e7f731dcc73846b500062f52abfb58d575be13"
+                "reference": "b3933992f65e948dd600ed9a4fbef508388ce7ed"
             },
             "dist": {
                 "type": "zip",
-                "url": "https://api.github.com/repos/hhvm/hhast/zipball/a5e7f731dcc73846b500062f52abfb58d575be13",
-                "reference": "a5e7f731dcc73846b500062f52abfb58d575be13",
+                "url": "https://api.github.com/repos/hhvm/hhast/zipball/b3933992f65e948dd600ed9a4fbef508388ce7ed",
+                "reference": "b3933992f65e948dd600ed9a4fbef508388ce7ed",
                 "shasum": ""
             },
             "require": {
                 "facebook/difflib": "^1.0.0",
                 "facebook/hh-clilib": "^2.0.0",
-                "hhvm": "^4.0",
+                "hhvm": "^4.1",
                 "hhvm/hhvm-autoload": "^2.0.4",
                 "hhvm/hsl": "^4.0",
                 "hhvm/type-assert": "^3.1"
@@ -309,8 +309,11 @@
             },
             "bin": [
                 "bin/hhast-lint",
+                "bin/hhast-lint.hack",
                 "bin/hhast-inspect",
-                "bin/hhast-migrate"
+                "bin/hhast-inspect.hack",
+                "bin/hhast-migrate",
+                "bin/hhast-migrate.hack"
             ],
             "type": "library",
             "extra": {
@@ -322,7 +325,7 @@
             "license": [
                 "MIT"
             ],
-            "time": "2019-03-06T18:49:34+00:00"
+            "time": "2019-03-11T21:30:03+00:00"
         }
     ],
     "aliases": [],
diff --git a/src/Assert.hack b/src/Assert.hack
index 7b7d6c0..e8ca28b 100644
--- a/src/Assert.hack
+++ b/src/Assert.hack
@@ -512,7 +512,7 @@ abstract class Assert {
       if ($actual is KeyedContainer<_, _>) {
         $actual_value = idx($actual, $key ?as arraykey);
         $part = '['.\var_export($key, true).']';
-      } else if (is_object($actual)) {
+      } else if (\is_object($actual)) {
         $actual_value = /* UNSAFE_EXPR */ $actual->$key;
         $part = "->".$key;
       } else {
@@ -520,7 +520,7 @@ abstract class Assert {
         $part = null;
       }
 
-      if (is_any_array($value) || is_object($value)) {
+      if (is_any_array($value) || \is_object($value)) {
         $this->assertSubset($value, $actual_value, $msg, $path.$part);
       } else {
         $this->assertEquals($value, $actual_value, $msg."\nKey: ".$path.$part);
diff --git a/src/ExpectObj.hack b/src/ExpectObj.hack
index a91be83..714e2a9 100644
--- a/src/ExpectObj.hack
+++ b/src/ExpectObj.hack
@@ -295,7 +295,7 @@ class ExpectObj<T> extends Assert {
     /* HH_FIXME[4110] KeyedContainer<_, _> always has arraykey keys */
     $this->assertKeyAndValueEquals(
       $expected as KeyedContainer<_, _>,
-      is_array($value) ? $value : [],
+      \is_array($value) ? $value : [],
       $msg,
     );
   }
diff --git a/src/utils.hack b/src/utils.hack
index 0188187..168212c 100644
--- a/src/utils.hack
+++ b/src/utils.hack
@@ -11,7 +11,7 @@ namespace Facebook\FBExpect;
 
 function is_any_array(mixed $value): bool {
   return (
-    is_array($value) ||
+    \is_array($value) ||
     ($value is dict<_, _>) ||
     ($value is vec<_>) ||
     ($value is keyset<_>)
@@ -19,7 +19,7 @@ function is_any_array(mixed $value): bool {
 }
 
 function not_hack_array(mixed $value): mixed {
-  if (is_any_array($value) && !is_array($value)) {
+  if (is_any_array($value) && !\is_array($value)) {
     /* HH_IGNORE_ERROR[4007] sketchy array cast */
     return (array) $value;
   }
@@ -27,14 +27,14 @@ function not_hack_array(mixed $value): mixed {
 }
 
 function print_type(mixed $value): string {
-  if (is_object($value)) {
+  if (\is_object($value)) {
     return \get_class($value);
   }
   return \gettype($value);
 }
 
 function is_iterable(mixed $value): bool {
-  return is_array($value) || (is_object($value) && ($value instanceof Traversable));
+  return \is_array($value) || (\is_object($value) && ($value instanceof Traversable));
 }
 
 function is_type(mixed $value): bool {