diff --git a/.hhconfig b/.hhconfig
index 0c2153c..3d59636 100644
--- a/.hhconfig
+++ b/.hhconfig
@@ -1 +1,2 @@
 assume_php=false
+enable_experimental_tc_features = safe_pass_by_ref, safe_array, safe_vector_array, contextual_inference
diff --git a/.travis.sh b/.travis.sh
index 01f5c66..a5bd904 100755
--- a/.travis.sh
+++ b/.travis.sh
@@ -11,8 +11,5 @@ hh_server --check $(pwd)
 hhvm -d hhvm.php7.all=0 vendor/bin/phpunit tests/
 hhvm -d hhvm.php7.all=1 vendor/bin/phpunit tests/
 
-HHVM_VERSION=$(hhvm --php -r 'echo HHVM_VERSION_ID;' 2>/dev/null);
-if [ $HHVM_VERSION -ge 32200 -a $HHVM_VERSION -lt 32300 ]; then
-  echo enable_experimental_tc_features = optional_shape_field, unknown_fields_shape_is_not_subtype_of_known_fields_shape >> .hhconfig
-  hh_server --check $(pwd)
-fi
+sed -i '/enable_experimental_tc_features/d' .hhconfig
+hh_server --check $(pwd)
diff --git a/.travis.yml b/.travis.yml
index 610db6f..c662f6c 100644
--- a/.travis.yml
+++ b/.travis.yml
@@ -3,7 +3,6 @@ language: generic
 services:
  - docker
 env:
- - HHVM_VERSION=3.21-lts-latest
  - HHVM_VERSION=latest
  - HHVM_VERSION=nightly
 install:
diff --git a/composer.json b/composer.json
index ec36309..7278836 100644
--- a/composer.json
+++ b/composer.json
@@ -4,6 +4,7 @@
   "keywords": ["hack", "router", "routing", "hhvm"],
   "homepage": "https://github.com/hhvm/hack-router",
   "require": {
+    "hhvm": "^3.23.0",
     "hack-psr/psr7-http-message-hhi": "^0.2.0|^1.0.0",
     "hhvm/hsl": "^1.0.0",
     "hhvm/hhvm-autoload": "^1.5.3"
@@ -17,6 +18,6 @@
     "phpunit/phpunit": "^5.1",
     "91carriage/phpunit-hhi": "^5.1",
     "zendframework/zend-diactoros": "^1.3",
-    "facebook/fbexpect": "^0.3.0"
+    "facebook/fbexpect": "^0.4.0"
   }
 }
diff --git a/composer.lock b/composer.lock
index 63d72ce..7219372 100644
--- a/composer.lock
+++ b/composer.lock
@@ -4,24 +4,24 @@
         "Read more about it at https://getcomposer.org/doc/01-basic-usage.md#composer-lock-the-lock-file",
         "This file is @generated automatically"
     ],
-    "content-hash": "71720f557a6fcd3dc35eeffad187a014",
+    "content-hash": "6e5c7426697148c0a6101682db652352",
     "packages": [
         {
             "name": "facebook/definition-finder",
-            "version": "v1.6.3",
+            "version": "v1.6.4",
             "source": {
                 "type": "git",
                 "url": "https://github.com/hhvm/definition-finder.git",
-                "reference": "38f37b3eafec26fd5030c0f9f3584fc6493c9a9b"
+                "reference": "e39f5e2a6e3636e5a8cdb1670188c5c728b13470"
             },
             "dist": {
                 "type": "zip",
-                "url": "https://api.github.com/repos/hhvm/definition-finder/zipball/38f37b3eafec26fd5030c0f9f3584fc6493c9a9b",
-                "reference": "38f37b3eafec26fd5030c0f9f3584fc6493c9a9b",
+                "url": "https://api.github.com/repos/hhvm/definition-finder/zipball/e39f5e2a6e3636e5a8cdb1670188c5c728b13470",
+                "reference": "e39f5e2a6e3636e5a8cdb1670188c5c728b13470",
                 "shasum": ""
             },
             "require": {
-                "hhvm": "~3.12"
+                "hhvm": "~3.23"
             },
             "require-dev": {
                 "91carriage/phpunit-hhi": "~5.1",
@@ -46,7 +46,7 @@
                 "hack",
                 "hhvm"
             ],
-            "time": "2017-10-10T23:29:38+00:00"
+            "time": "2018-01-05T20:56:28+00:00"
         },
         {
             "name": "fredemmott/hack-error-suppressor",
@@ -122,23 +122,23 @@
         },
         {
             "name": "hhvm/hhvm-autoload",
-            "version": "v1.5.3",
+            "version": "v1.5.4",
             "source": {
                 "type": "git",
                 "url": "https://github.com/hhvm/hhvm-autoload.git",
-                "reference": "e91e24c69118505999e6f7e9e051b03c85f634b4"
+                "reference": "20aa3b34de71a337644a146f2abbafe491fd3bb2"
             },
             "dist": {
                 "type": "zip",
-                "url": "https://api.github.com/repos/hhvm/hhvm-autoload/zipball/e91e24c69118505999e6f7e9e051b03c85f634b4",
-                "reference": "e91e24c69118505999e6f7e9e051b03c85f634b4",
+                "url": "https://api.github.com/repos/hhvm/hhvm-autoload/zipball/20aa3b34de71a337644a146f2abbafe491fd3bb2",
+                "reference": "20aa3b34de71a337644a146f2abbafe491fd3bb2",
                 "shasum": ""
             },
             "require": {
                 "composer-plugin-api": "^1.0",
-                "facebook/definition-finder": "^1.0",
+                "facebook/definition-finder": "~1.6.4",
                 "fredemmott/hack-error-suppressor": "^1.0",
-                "hhvm": "^3.12"
+                "hhvm": "^3.23"
             },
             "replace": {
                 "facebook/hhvm-autoload": "1.*"
@@ -168,20 +168,20 @@
                 ]
             },
             "notification-url": "https://packagist.org/downloads/",
-            "time": "2017-10-20T01:23:28+00:00"
+            "time": "2018-01-05T21:10:38+00:00"
         },
         {
             "name": "hhvm/hsl",
-            "version": "v1.0.0",
+            "version": "v1.2.0",
             "source": {
                 "type": "git",
                 "url": "https://github.com/hhvm/hsl.git",
-                "reference": "99ed4bce2170d12e38654f8502482fcac5b80352"
+                "reference": "ef61c015ab5969d10c2b0d66cfbc1dd20b13ec17"
             },
             "dist": {
                 "type": "zip",
-                "url": "https://api.github.com/repos/hhvm/hsl/zipball/99ed4bce2170d12e38654f8502482fcac5b80352",
-                "reference": "99ed4bce2170d12e38654f8502482fcac5b80352",
+                "url": "https://api.github.com/repos/hhvm/hsl/zipball/ef61c015ab5969d10c2b0d66cfbc1dd20b13ec17",
+                "reference": "ef61c015ab5969d10c2b0d66cfbc1dd20b13ec17",
                 "shasum": ""
             },
             "require": {
@@ -190,14 +190,14 @@
             "require-dev": {
                 "91carriage/phpunit-hhi": "^5.7",
                 "facebook/definition-finder": "^1.6.1",
-                "facebook/fbexpect": "^0.2",
-                "hhvm": "^3.21.3",
+                "facebook/fbexpect": "^0.4",
+                "hhvm": "^3.23.2",
                 "phpunit/phpunit": "^5.7"
             },
             "type": "library",
             "notification-url": "https://packagist.org/downloads/",
             "description": "The Hack Standard Library",
-            "time": "2017-10-26T18:38:35+00:00"
+            "time": "2018-01-05T23:38:40+00:00"
         },
         {
             "name": "psr/http-message",
@@ -253,14 +253,14 @@
     "packages-dev": [
         {
             "name": "91carriage/phpunit-hhi",
-            "version": "5.7.1",
+            "version": "5.7.2",
             "source": {
                 "type": "git",
                 "url": "https://git.simon.geek.nz/91-carriage/phpunit-hhi.git",
-                "reference": "6864897f023f111d8b72fb7340c1ef5d0d9f8a45"
+                "reference": "b2ca7d221fa4ac6b4331e0dbc32cdc918ab8b11f"
             },
             "require": {
-                "hhvm": ">=3.12.0"
+                "hhvm": ">=3.23.0"
             },
             "conflict": {
                 "phpunit/phpunit": "<5.7.15"
@@ -298,7 +298,7 @@
                 "phpunit",
                 "testing"
             ],
-            "time": "2017-04-09T02:42:01+00:00"
+            "time": "2018-01-09T08:14:01+00:00"
         },
         {
             "name": "doctrine/instantiator",
@@ -356,20 +356,21 @@
         },
         {
             "name": "facebook/fbexpect",
-            "version": "v0.3",
+            "version": "v0.4",
             "source": {
                 "type": "git",
                 "url": "https://github.com/hhvm/fbexpect.git",
-                "reference": "d650f97d7da0b7bbaf7a3641feca4cdb41414dce"
+                "reference": "21e8ea201df6555bcf014a75560426650c7d961b"
             },
             "dist": {
                 "type": "zip",
-                "url": "https://api.github.com/repos/hhvm/fbexpect/zipball/d650f97d7da0b7bbaf7a3641feca4cdb41414dce",
-                "reference": "d650f97d7da0b7bbaf7a3641feca4cdb41414dce",
+                "url": "https://api.github.com/repos/hhvm/fbexpect/zipball/21e8ea201df6555bcf014a75560426650c7d961b",
+                "reference": "21e8ea201df6555bcf014a75560426650c7d961b",
                 "shasum": ""
             },
             "require": {
                 "91carriage/phpunit-hhi": "^5.7",
+                "hhvm": "^3.23",
                 "phpunit/phpunit": "^5.7"
             },
             "type": "library",
@@ -384,7 +385,7 @@
             },
             "notification-url": "https://packagist.org/downloads/",
             "description": "Unit test helpers for Facebook projects",
-            "time": "2017-09-20T18:27:43+00:00"
+            "time": "2018-01-05T21:25:50+00:00"
         },
         {
             "name": "myclabs/deep-copy",
@@ -487,22 +488,22 @@
         },
         {
             "name": "phpdocumentor/reflection-docblock",
-            "version": "3.2.2",
+            "version": "3.3.2",
             "source": {
                 "type": "git",
                 "url": "https://github.com/phpDocumentor/ReflectionDocBlock.git",
-                "reference": "4aada1f93c72c35e22fb1383b47fee43b8f1d157"
+                "reference": "bf329f6c1aadea3299f08ee804682b7c45b326a2"
             },
             "dist": {
                 "type": "zip",
-                "url": "https://api.github.com/repos/phpDocumentor/ReflectionDocBlock/zipball/4aada1f93c72c35e22fb1383b47fee43b8f1d157",
-                "reference": "4aada1f93c72c35e22fb1383b47fee43b8f1d157",
+                "url": "https://api.github.com/repos/phpDocumentor/ReflectionDocBlock/zipball/bf329f6c1aadea3299f08ee804682b7c45b326a2",
+                "reference": "bf329f6c1aadea3299f08ee804682b7c45b326a2",
                 "shasum": ""
             },
             "require": {
-                "php": ">=5.5",
-                "phpdocumentor/reflection-common": "^1.0@dev",
-                "phpdocumentor/type-resolver": "^0.3.0",
+                "php": "^5.6 || ^7.0",
+                "phpdocumentor/reflection-common": "^1.0.0",
+                "phpdocumentor/type-resolver": "^0.4.0",
                 "webmozart/assert": "^1.0"
             },
             "require-dev": {
@@ -528,20 +529,20 @@
                 }
             ],
             "description": "With this component, a library can provide support for annotations via DocBlocks or otherwise retrieve information that is embedded in a DocBlock.",
-            "time": "2017-08-08T06:39:58+00:00"
+            "time": "2017-11-10T14:09:06+00:00"
         },
         {
             "name": "phpdocumentor/type-resolver",
-            "version": "0.3.0",
+            "version": "0.4.0",
             "source": {
                 "type": "git",
                 "url": "https://github.com/phpDocumentor/TypeResolver.git",
-                "reference": "fb3933512008d8162b3cdf9e18dba9309b7c3773"
+                "reference": "9c977708995954784726e25d0cd1dddf4e65b0f7"
             },
             "dist": {
                 "type": "zip",
-                "url": "https://api.github.com/repos/phpDocumentor/TypeResolver/zipball/fb3933512008d8162b3cdf9e18dba9309b7c3773",
-                "reference": "fb3933512008d8162b3cdf9e18dba9309b7c3773",
+                "url": "https://api.github.com/repos/phpDocumentor/TypeResolver/zipball/9c977708995954784726e25d0cd1dddf4e65b0f7",
+                "reference": "9c977708995954784726e25d0cd1dddf4e65b0f7",
                 "shasum": ""
             },
             "require": {
@@ -575,20 +576,20 @@
                     "email": "me@mikevanriel.com"
                 }
             ],
-            "time": "2017-06-03T08:32:36+00:00"
+            "time": "2017-07-14T14:27:02+00:00"
         },
         {
             "name": "phpspec/prophecy",
-            "version": "v1.7.2",
+            "version": "1.7.3",
             "source": {
                 "type": "git",
                 "url": "https://github.com/phpspec/prophecy.git",
-                "reference": "c9b8c6088acd19d769d4cc0ffa60a9fe34344bd6"
+                "reference": "e4ed002c67da8eceb0eb8ddb8b3847bb53c5c2bf"
             },
             "dist": {
                 "type": "zip",
-                "url": "https://api.github.com/repos/phpspec/prophecy/zipball/c9b8c6088acd19d769d4cc0ffa60a9fe34344bd6",
-                "reference": "c9b8c6088acd19d769d4cc0ffa60a9fe34344bd6",
+                "url": "https://api.github.com/repos/phpspec/prophecy/zipball/e4ed002c67da8eceb0eb8ddb8b3847bb53c5c2bf",
+                "reference": "e4ed002c67da8eceb0eb8ddb8b3847bb53c5c2bf",
                 "shasum": ""
             },
             "require": {
@@ -600,7 +601,7 @@
             },
             "require-dev": {
                 "phpspec/phpspec": "^2.5|^3.2",
-                "phpunit/phpunit": "^4.8 || ^5.6.5"
+                "phpunit/phpunit": "^4.8.35 || ^5.7"
             },
             "type": "library",
             "extra": {
@@ -638,7 +639,7 @@
                 "spy",
                 "stub"
             ],
-            "time": "2017-09-04T11:05:03+00:00"
+            "time": "2017-11-24T13:59:53+00:00"
         },
         {
             "name": "phpunit/php-code-coverage",
@@ -705,16 +706,16 @@
         },
         {
             "name": "phpunit/php-file-iterator",
-            "version": "1.4.2",
+            "version": "1.4.5",
             "source": {
                 "type": "git",
                 "url": "https://github.com/sebastianbergmann/php-file-iterator.git",
-                "reference": "3cc8f69b3028d0f96a9078e6295d86e9bf019be5"
+                "reference": "730b01bc3e867237eaac355e06a36b85dd93a8b4"
             },
             "dist": {
                 "type": "zip",
-                "url": "https://api.github.com/repos/sebastianbergmann/php-file-iterator/zipball/3cc8f69b3028d0f96a9078e6295d86e9bf019be5",
-                "reference": "3cc8f69b3028d0f96a9078e6295d86e9bf019be5",
+                "url": "https://api.github.com/repos/sebastianbergmann/php-file-iterator/zipball/730b01bc3e867237eaac355e06a36b85dd93a8b4",
+                "reference": "730b01bc3e867237eaac355e06a36b85dd93a8b4",
                 "shasum": ""
             },
             "require": {
@@ -748,7 +749,7 @@
                 "filesystem",
                 "iterator"
             ],
-            "time": "2016-10-03T07:40:28+00:00"
+            "time": "2017-11-27T13:52:08+00:00"
         },
         {
             "name": "phpunit/php-text-template",
@@ -842,16 +843,16 @@
         },
         {
             "name": "phpunit/php-token-stream",
-            "version": "1.4.11",
+            "version": "1.4.12",
             "source": {
                 "type": "git",
                 "url": "https://github.com/sebastianbergmann/php-token-stream.git",
-                "reference": "e03f8f67534427a787e21a385a67ec3ca6978ea7"
+                "reference": "1ce90ba27c42e4e44e6d8458241466380b51fa16"
             },
             "dist": {
                 "type": "zip",
-                "url": "https://api.github.com/repos/sebastianbergmann/php-token-stream/zipball/e03f8f67534427a787e21a385a67ec3ca6978ea7",
-                "reference": "e03f8f67534427a787e21a385a67ec3ca6978ea7",
+                "url": "https://api.github.com/repos/sebastianbergmann/php-token-stream/zipball/1ce90ba27c42e4e44e6d8458241466380b51fa16",
+                "reference": "1ce90ba27c42e4e44e6d8458241466380b51fa16",
                 "shasum": ""
             },
             "require": {
@@ -887,20 +888,20 @@
             "keywords": [
                 "tokenizer"
             ],
-            "time": "2017-02-27T10:12:30+00:00"
+            "time": "2017-12-04T08:55:13+00:00"
         },
         {
             "name": "phpunit/phpunit",
-            "version": "5.7.23",
+            "version": "5.7.26",
             "source": {
                 "type": "git",
                 "url": "https://github.com/sebastianbergmann/phpunit.git",
-                "reference": "78532d5269d984660080d8e0f4c99c5c2ea65ffe"
+                "reference": "7fbc25c13309de0c4c9bb48b7361f1eca34c7fbd"
             },
             "dist": {
                 "type": "zip",
-                "url": "https://api.github.com/repos/sebastianbergmann/phpunit/zipball/78532d5269d984660080d8e0f4c99c5c2ea65ffe",
-                "reference": "78532d5269d984660080d8e0f4c99c5c2ea65ffe",
+                "url": "https://api.github.com/repos/sebastianbergmann/phpunit/zipball/7fbc25c13309de0c4c9bb48b7361f1eca34c7fbd",
+                "reference": "7fbc25c13309de0c4c9bb48b7361f1eca34c7fbd",
                 "shasum": ""
             },
             "require": {
@@ -925,7 +926,7 @@
                 "sebastian/object-enumerator": "~2.0",
                 "sebastian/resource-operations": "~1.0",
                 "sebastian/version": "~1.0.3|~2.0",
-                "symfony/yaml": "~2.1|~3.0"
+                "symfony/yaml": "~2.1|~3.0|~4.0"
             },
             "conflict": {
                 "phpdocumentor/reflection-docblock": "3.0.2"
@@ -969,7 +970,7 @@
                 "testing",
                 "xunit"
             ],
-            "time": "2017-10-15T06:13:55+00:00"
+            "time": "2017-12-17T06:14:38+00:00"
         },
         {
             "name": "phpunit/phpunit-mock-objects",
@@ -1545,23 +1546,26 @@
         },
         {
             "name": "symfony/yaml",
-            "version": "v3.3.10",
+            "version": "v3.4.3",
             "source": {
                 "type": "git",
                 "url": "https://github.com/symfony/yaml.git",
-                "reference": "8c7bf1e7d5d6b05a690b715729cb4cd0c0a99c46"
+                "reference": "25c192f25721a74084272671f658797d9e0e0146"
             },
             "dist": {
                 "type": "zip",
-                "url": "https://api.github.com/repos/symfony/yaml/zipball/8c7bf1e7d5d6b05a690b715729cb4cd0c0a99c46",
-                "reference": "8c7bf1e7d5d6b05a690b715729cb4cd0c0a99c46",
+                "url": "https://api.github.com/repos/symfony/yaml/zipball/25c192f25721a74084272671f658797d9e0e0146",
+                "reference": "25c192f25721a74084272671f658797d9e0e0146",
                 "shasum": ""
             },
             "require": {
                 "php": "^5.5.9|>=7.0.8"
             },
+            "conflict": {
+                "symfony/console": "<3.4"
+            },
             "require-dev": {
-                "symfony/console": "~2.8|~3.0"
+                "symfony/console": "~3.4|~4.0"
             },
             "suggest": {
                 "symfony/console": "For validating YAML files using the lint command"
@@ -1569,7 +1573,7 @@
             "type": "library",
             "extra": {
                 "branch-alias": {
-                    "dev-master": "3.3-dev"
+                    "dev-master": "3.4-dev"
                 }
             },
             "autoload": {
@@ -1596,7 +1600,7 @@
             ],
             "description": "Symfony Yaml Component",
             "homepage": "https://symfony.com",
-            "time": "2017-10-05T14:43:42+00:00"
+            "time": "2018-01-03T07:37:34+00:00"
         },
         {
             "name": "webmozart/assert",
@@ -1650,16 +1654,16 @@
         },
         {
             "name": "zendframework/zend-diactoros",
-            "version": "1.6.1",
+            "version": "1.7.0",
             "source": {
                 "type": "git",
                 "url": "https://github.com/zendframework/zend-diactoros.git",
-                "reference": "c8664b92a6d5bc229e48b0923486c097e45a7877"
+                "reference": "ed6ce7e2105c400ca10277643a8327957c0384b7"
             },
             "dist": {
                 "type": "zip",
-                "url": "https://api.github.com/repos/zendframework/zend-diactoros/zipball/c8664b92a6d5bc229e48b0923486c097e45a7877",
-                "reference": "c8664b92a6d5bc229e48b0923486c097e45a7877",
+                "url": "https://api.github.com/repos/zendframework/zend-diactoros/zipball/ed6ce7e2105c400ca10277643a8327957c0384b7",
+                "reference": "ed6ce7e2105c400ca10277643a8327957c0384b7",
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             },
             "require": {
@@ -1678,8 +1682,8 @@
             "type": "library",
             "extra": {
                 "branch-alias": {
-                    "dev-master": "1.6-dev",
-                    "dev-develop": "1.7-dev"
+                    "dev-master": "1.7.x-dev",
+                    "dev-develop": "1.8.x-dev"
                 }
             },
             "autoload": {
@@ -1698,7 +1702,7 @@
                 "psr",
                 "psr-7"
             ],
-            "time": "2017-10-12T15:24:51+00:00"
+            "time": "2018-01-04T18:21:48+00:00"
         }
     ],
     "aliases": [],
@@ -1706,6 +1710,8 @@
     "stability-flags": [],
     "prefer-stable": false,
     "prefer-lowest": false,
-    "platform": [],
+    "platform": {
+        "hhvm": "^3.23.0"
+    },
     "platform-dev": []
 }
diff --git a/src/router/PrefixMatchingResolver.php b/src/router/PrefixMatchingResolver.php
index 7e7f8f1..26ff70c 100644
--- a/src/router/PrefixMatchingResolver.php
+++ b/src/router/PrefixMatchingResolver.php
@@ -66,7 +66,7 @@ private function resolveWithMap(
       $pattern = '#^'.$regexp.'#';
       $matches = [];
 
-      if (preg_match($pattern, $path, $matches) !== 1) {
+      if (preg_match($pattern, $path, &$matches) !== 1) {
         continue;
       }
       $matched = $matches[0];
diff --git a/src/router/SimpleRegexpResolver.php b/src/router/SimpleRegexpResolver.php
index 9405bd2..dab0560 100644
--- a/src/router/SimpleRegexpResolver.php
+++ b/src/router/SimpleRegexpResolver.php
@@ -35,7 +35,7 @@ public function resolve(
     $map = $this->map[$method];
     foreach ($map as $regexp => $responder) {
       $matches = [];
-      if (preg_match($regexp, $path, $matches) !== 1) {
+      if (preg_match($regexp, $path, &$matches) !== 1) {
         continue;
       }
       $ret =